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Question 1
Correct
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Absorption of protein antigens i.e. bacterial and viral proteins takes place in the:
Your Answer: Microfold cells (m cells) of the intestine
Explanation:M cells are specialized epithelial cells. They have a high capacity of transcytosis of microorganisms and macromolecules. They rapidly uptake antigens and present them to immune cells associated with the gut. In contrast to absorptive enterocytes, M cells do not exert direct defence mechanisms to antigens and pathogens in the intestinal cavity. Crypts of Lieberkühn are located mainly in the small intestine and large intestine and the main function is to replenish epithelial cells and to secrete intestinal enzymatic juice as well as mucous. Brunner’s glands empty into intestinal glands and their main function is to secrete mucin and to form a protective mucus layer on the duodenal epithelial cells to protect it from acidic chyme coming from the stomach. Islets of Langerhans are located in the pancreas and secrets insulin mainly. Mucosa associated lymphoid tissue plays a role in inducing immune response after presentation of antigens.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 2
Correct
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Activation of nitric oxide synthesis by endothelial cells is triggered by:
Your Answer: All of the above
Explanation:Acetylcholine, histamine, bradykinin, vasoactive intestinal peptide (VIP) and shear stress on the endothelial cells causing the release of NO. NO is formed from arginine and causes vasodilatation of the blood vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Correct
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What is the most important source of heat production in the body?
Your Answer: Skeletal muscle contraction
Explanation:Thermogenesis is the process by which organisms produce heat. Through skeletal muscle contraction, or shivering, ATP is converted into kinetic energy, some of which converts into heat. These muscle contractions produce about 70% of total body heat.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 4
Correct
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Which hormone secreting cell of the human anterior pituitary gland secretes growth hormone?
Your Answer: Somatotroph
Explanation:Somatotroph cells are responsible for the production of growth hormone. Somatotrophs occupy nearly 40% of the total surface area of the anterior pituitary, and they are acidophilic in nature.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 5
Correct
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ANP and BNP in the circulation act on the kidney to?
Your Answer: Increase sodium excretion
Explanation:The physiologic actions of BNP are similar to those of ANP and include decrease in systemic vascular resistance and central venous pressure as well as an increase in natriuresis (sodium excretion). The net effect of these peptides is a decrease in blood pressure due to the decrease in systemic vascular resistance and, thus, afterload.
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This question is part of the following fields:
- Medicine
- Renal
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Question 6
Correct
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With regards to environmental temperature, for each degree Celsius of elevation, the metabolic rate rises?
Your Answer: 0.14
Explanation:An increase in body temperature is associated with a higher metabolic rate. Evidence suggests that an increase of 1°C in your body temperature increases your metabolism by 10 to 14%.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 7
Correct
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Question 8
Correct
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Which afferent information is carried by the dorsal column?
Your Answer: Proprioception/ discriminative touch
Explanation:The posterior grey column (dorsal column) is responsible for carrying the sensation of proprioception, two-point discrimination, and vibration to the nucleus proprius, situated anterior to the substantia gelatinosa throughout the spinal cord.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 9
Correct
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Which of the following biochemical profiles is seen in a normal 65 year old female? (in comparison to a normal 24 yr. old female)
Your Answer: Increased FSH, LH; decreased oestrogen, progesterone
Explanation:During menopause, a woman’s number of ovarian follicles becomes depleted; as a result, oestrogen and progesterone levels drop, and LH and FSH levels increase. One of the criteria to diagnose menopause is the absence of menstrual period for a year, along with a serum FSH level increased to 30 mIU/ml or higher. LH also rises with the onset of menopause.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 10
Incorrect
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Where is leptin synthesized and secreted?
Your Answer: Yellow adipose tissue
Correct Answer: White adipose tissue
Explanation:Leptin is a hormone that helps regulate food intake and energy expenditure. It is synthetized by white adipose tissue and the gastric mucosa. It works by inhibiting the sensation of hunger, therefore, it opposes the actions of ghrelin, also known as the hunger hormone.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 11
Correct
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Which statement is correct?
Your Answer: MtDNA principally encodes for proteins that are involved in oxidative phosphorylation for the production of ATP in the cell.
Explanation:Mitochondria have no nucleus instead they contain their own free floating circular genome (MtDNA), which encodes 13 different subunits of proteins involved in oxidative phosphorylation. The remainder of the mitochondrial proteins are nuclear encoded, synthesized in the cytoplasm, and transported into the mitochondria.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 12
Correct
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Lymphoid stem cells give rise to the following cells:
Your Answer: T cells, b cells and natural killer cells
Explanation:T Cells, B Cells and NK Cells (and all other Innate lymphoid cells) are unique to the lymphocyte family, but dendritic cells are not. Dendritic cells of identical appearance but different markers are spread throughout the body, and come from either lymphoid and myeloid lineages.
Myeloid stem cells lead to myeloblasts, which evolve into macrophages, monocytes, neutrophils, basophils, and eosinophils.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 13
Correct
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Question 14
Correct
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The process in which tissue thromboplastin activates factor VII is best known as:
Your Answer: The extrinsic pathway
Explanation:In the tissue factor pathway (extrinsic), following damage to the blood vessel, FVII leaves the circulation and comes into contact with tissue factor (TF) expressed on tissue-factor-bearing cells (stromal fibroblasts and leukocytes), forming an activated complex (TF-FVIIa).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 15
Correct
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The chief cells of the stomach secrete which of the following?
Your Answer: Pepsinogens
Explanation:A gastric chief cell (or peptic cell, or gastric zymogenic cell) is a type of cell in the stomach that releases pepsinogen and gastric lipase.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 16
Incorrect
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A 30-year-old woman is admitted for drainage of an abscess in her left forearm. She has revealed that she was regular heroin user and has stopped for the past few days. Clinical signs are pointing towards opioid withdrawal. What is the next step in managing this patient?
Your Answer: Ask her how much heroin she uses per day and arrange for her to receive methadone syrup equivalent to this divided into four doses per day
Correct Answer: Give her 10 mg of methadone syrup and wait 60 min to determine its effect
Explanation:The next step in managing this patient is to give 10 mg and continue administering in 10 mg increments each hour until symptoms are under control.Methadone alleviates opioid withdrawal symptoms and reduces cravings. Methadone is useful for detoxification from longer-acting opioids such as morphine or methadone itself.Methadone should be used with caution if the patient has:Respiratory deficiencyAcute alcohol dependenceHead injuryTreatment with monoamine oxidase inhibitors (MAOIs)Ulcerating colitis or Crohn’s diseaseSevere hepatic impairmentThe dose must be reviewed on a daily basis and adjusted based upon how well the symptoms are controlled and the presence of side effects. The greater the dose of opioids used by the patient, the greater the dose of methadone required to control withdrawal symptoms. To avoid the risk of overdose in the first days of treatment The recommended dosing of methadone is 30mg in two doses of 15mg morning and evening.It is important to note that a methadone dose equivalent to what the patient reports they are taking should never be given. It is rare to need more than 40 mg per 24 hours: beware of overdosing which can lead to respiratory arrest.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 17
Correct
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Question 18
Incorrect
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Endothelial cells are attached to adjacent cells by adherent junctions via:
Your Answer: None of the above
Correct Answer: Cadherins
Explanation:Cadherins are calcium dependant molecules that mediate cell to cell adhesions in epithelial and endothelial cells among others.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 19
Correct
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The principle by which the energy of contraction is proportional to the initial length of cardiac muscle fiber is known as:
Your Answer: Starling’s law
Explanation:The Frank starling relationship describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increase venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and increased development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relation is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 20
Correct
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Which cell type functions as the critical bridge between innate and adaptive immune systems, by activating naïve T lymphocytes?
Your Answer: Dendritic cells
Explanation:Dendritic cells are antigen presenting cells. They express class II MHC and T cell co-stimulatory molecules. They bind antigens and present them to native T cells and in the process activate the specific T cell against that antigen.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 21
Correct
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Which one of the following is most likely to be seen in a patient with multiple endocrine neoplasia (MEN) type I?
Your Answer: Insulinoma
Explanation:Multiple endocrine neoplasia type 1 (MEN-1 syndrome) or Wermer’s syndrome is part of a group of disorders, the multiple endocrine neoplasias, that affect the endocrine system through development of neoplastic lesions in the ‘three P’s’:Parathyroid (>90%): hyperparathyroidism due to parathyroid hyperplasiaPituitary (15-42%)Pancreas (60-70%, e.g. insulinoma, gastrinoma)
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 22
Correct
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The main efferent input of the posterior pituitary gland comes from:
Your Answer: Paracrine hormones secreted from the hypothalamus via axons.
Explanation:The posterior pituitary or neurohypophysis consists of a collection of axonal projections emerging from the hypothalamus. It releases hormones directly from these axonal endings into circulation; these hormones are oxytocin and vasopressin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 23
Correct
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The ENaC Transporter occurs in which part of the renal tubule?
Your Answer: Collecting duct
Explanation:The epithelial sodium channel (ENaC) is a membrane-bound ion channel that is selectively permeable to Na+ ions. It is involved primarily in the reabsorption of sodium ions at the collecting ducts of the kidney’s nephrons.
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This question is part of the following fields:
- Medicine
- Renal
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Question 24
Incorrect
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Which one of the following antibiotics is safest to use in pregnancy?
Your Answer: Metronidazole
Correct Answer: Erythromycin
Explanation:Antibiotics that should be avoided in pregnancy are included in the mnemonic: Countless SAFe Moms Take Really Good Care -Clarithromycin, Sulphonamides, Aminoglycosides, Fluoroquinolones, Metronidazole, Tetracyclines, Ribavirin, Griseofulvin, Chloramphenicol
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 25
Correct
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The following play a role in regulation of intestinal iron absorption except:
Your Answer: Urinary iron excretion rate
Explanation:The human body’s rate of iron absorption appears to respond to a variety of interdependent factors, including total iron stores, dietary intake, the extent to which the bone marrow is producing new red blood cells, the concentration of haemoglobin in the blood, and the oxygen content of the blood. Classic examples of genetic iron overload includes hereditary hemochromatosis (HH) and the more severe disease juvenile hemochromatosis (JH).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 26
Correct
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The conversion of haem to bilirubin is catalysed by which of these enzymes?
Your Answer: Biliverdin reductase
Explanation:Bilirubin is created by the activity of biliverdin reductase on biliverdin, a green tetrapyrrolic bile pigment that is also a product of haem catabolism.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 27
Incorrect
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The parasympathetic innervation of the parotid salivary gland arrives from the salivary nuclei:
Your Answer: CN VII
Correct Answer: CN IX
Explanation:Parasympathetic presynaptic nerve fibers from the glossopharyngeal nerve (CN IX) synapse in the otic ganglion and the postsynaptic parasympathetic nerve fibers pass to the parotid gland via the auriculotemporal nerve.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 28
Correct
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A 46 year old male, known with Rheumatoid Arthritis presents with a swollen and painful right ankle. No drug allergies are reported. On examination, the vitals are as follows: Temp: 38.8BP: 90/60 mmHgPulse: 110/min. Right ankle examination reveals tenderness, warmth, erythema and tense joint effusion. Blood samples including blood cultures are collected and fluid resuscitation is initiated. Which of the following interventions would be most appropriate for this man?
Your Answer: Administer i.v. flucloxacillin, and arrange joint aspiration urgently
Explanation:Although microscopic analysis of joint fluid aspirate and culture is the basis of septic arthritis diagnosis and should usually be collected before the administration of antibiotics, the patient is showing signs of septic shock. A delay in antibiotics might lead to worsening of symptoms so they are administered first.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 29
Incorrect
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The formation of superoxide is catalysed by which enzyme?
Your Answer: Superoxide dismutase
Correct Answer: NADPH oxidase
Explanation:Superoxide is biologically toxic and is deployed by the immune system to kill invading microorganisms. In phagocytes, superoxide is produced in large quantities by the enzyme NADPH oxidase for use in oxygen-dependent killing mechanisms of invading pathogens.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 30
Correct
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The internodal tract of Bachman:
Your Answer: Connects the SA node to the AV node
Explanation:Internodal tract of Bachman connects the SA node to the AV node conducting the electrical impulses generated from the SA node to the AV node and from the AV node to the rest of the electrical complex of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 31
Correct
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Which of the following is the most common route of hepatitis B transmission worldwide?
Your Answer: Perinatal transmission
Explanation:The virus is transmitted by exposure to infectious blood or body fluids. Infection around the time of birth or from contact with other people’s blood during childhood is the most frequent method by which hepatitis B is acquired in areas where the disease is common. In areas where the disease is rare, intravenous drug use and sexual intercourse are the most frequent routes of infection. Perinatal transmission is the most common and without intervention, a mother who is positive for HBsAg has a 20% risk of passing the infection to her offspring at the time of birth. This risk is as high as 90% if the mother is also positive for HBeAg.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 32
Correct
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Regarding the formation of CSF, which of the following is true?
Your Answer: Its composition resembles that of brain ECF
Explanation:In normal adults CSF volume is around 125ml to 150ml. Turnover of entire volume of cerebrospinal fluid a day is about 3 to 4 times a day. Composition of CSF is similar to that of plasma except that CSF is nearly protein-free compared with plasma and has a different electrolyte level. About 80% of CSF is produced by the choroid plexus. It is also produced by a single layer of column shaped ependymal cells. The composition and rate of CSF generation depends on several factors and is influenced by hormones and the content and pressure of blood and CSF.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 33
Correct
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In which phase do chromosomes in the nucleus become condensed into well-defined chromosomes?
Your Answer: Metaphase
Explanation:Prophase begins when the nucleus envelope disintegrates and the chromosomes start to condense. The chromosomes consist of two sister chromatids that are joined at a constriction known as centromere. When the cell reaches the metaphase the chromosomes are completely condensed and ready to align on the equatorial plate
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This question is part of the following fields:
- Genetics
- Medicine
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Question 34
Correct
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Which intercellular connections are responsible for fastening the cells to one another?
Your Answer: Hemidesmosomes, zonula adherens & desmosomes
Explanation:There are three major types of cell junction:Adherens junctions, desmosomes and hemidesmosomes (anchoring junctions),Gap junctions (communicating junction) &Tight junctions (occluding junctions)
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 35
Correct
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A 60 year old male presents with one month history of generalized headache, fever and malaise. He also complains of scalp sensitivity while combing his hair. In order to confirm the diagnosis, which of the following would be the definite test?
Your Answer: Temporal artery biopsy
Explanation:Temporal arteritis is a chronic large- and medium-sized vessel vasculitis that typically involves the temporal arteries. Classical symptoms include temporal headaches, jaw claudication, amaurosis fugax. Physical exam shows scalp tenderness, palpation of the temporal area may demonstrate an absent pulse, knot-like swelling, and vision loss. Lab results reveal an increased erythematous sedimentation rate and C-reactive protein. Temporal artery biopsy confirms the diagnosis. Management approach: high-dose systemic corticosteroids should be promptly administered even before the diagnosis is established. Temporal artery biopsy confirms the diagnosis. Inability to manage this or administer glucocorticoids might lead to development of blindness.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 36
Incorrect
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The following is true about the carotid arterial supply to the brain:
Your Answer: The 6 most important branches arise prior to the circle of Willis
Correct Answer: Following carotid occlusion, precapillary anastomoses are unable to prevent infarction
Explanation:The brain has two sources of blood supply; the internal carotid arteries which are the anterior segment or the main artery that supplies the anterior portion of the brain, and the vertebral arteries which is the posterior segment which supplies the posterior portion of the brain. The internal carotid arteries branch and form two major arteries anterior and middle cerebral arteries. The right and left vertebral arteries fuse together at the level of the pons on the anterior surface of the brainstem to form the midline basilar artery. The basilar artery joins the blood supply from the internal carotids in an arterial ring at the base of the brain called the circle of Willis. The anterior and posterior communicating arteries conjoin the two major sources of cerebral vascular supply via the circle of Willis improving the chances of any region of the brain continuing to receive blood if one of the major arteries becomes occluded.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 37
Correct
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An 80-year-old woman with advanced COPD has been admitted to the medicine ward in an unconscious state. She appears to have an acute lower respiratory tract infection. After consulting with an anaesthesiologist it was concluded that she was not a candidate for intensive care unit admission and thus, a decision was made to start the patient on doxapram therapy. Which of the following best fits the characteristics of doxapram?
Your Answer: It is contraindicated in hyperthyroidism
Explanation:The two statements that fit the characteristics of doxapram are, epilepsy is a contraindication for doxapram use and concurrent use with theophylline may increase agitation.Doxapram is a central respiratory stimulant. In clinical practice, doxapram is usually used for patients who have an acute exacerbation of chronic obstructive pulmonary disease (COPD) who are unsuitable for admission to the intensive therapy unit for ventilatory support. Doxapram infusion may buy an extra 24 h to allow for recovery.Contraindications include: ischaemic heart disease, epilepsy, cerebral oedema, acute stroke, asthma, hypertension, hyperthyroidism, and pheochromocytoma. The infusion may worsen agitation and dyspnoea and lead to hypertension, nausea, vomiting and urinary retention.Drug interactions:Concomitant administration of doxapram and aminophylline (theophylline) can cause increased skeletal muscle activity, agitation, and hyperactivity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 38
Correct
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Question 39
Correct
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Male to male transmission is a key factor of which type of inheritance?
Your Answer: Autosomal dominant
Explanation:Autosomal dominant type of inheritance can include both sexes in the same ratio. There is no skipping a generation and father to son transmission is common. The passing of the trait is sex independent.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 40
Correct
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Which of the following components regulate cardiac output?
Your Answer: All of the above
Explanation:Cardiac output is regulated by the autonomic nervous system with sympathetic nerves having a positive chronotropic and inotropic effect and parasympathetic nerves having the opposite effect. An increase in preload will increase cardiac output likewise an afterload increase will also increase cardiac output.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 41
Correct
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Myelin sheath in the CNS is produced by?
Your Answer: Oligodendrocytes
Explanation:CNS myelin is produced by special cells called oligodendrocytes. PNS myelin is produced by Schwann cells. The two types of myelin are chemically different, but they both perform the same function — to promote efficient transmission of a nerve impulse along the axon.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 42
Correct
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Bile salts are responsible for:
Your Answer: The emulsification of fats
Explanation:The main function of bile acids is to allow digestion of dietary fats and oils by acting as a surfactant that emulsifies them into micelles, allowing them to be colloidally suspended in the chyme before further processing.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 43
Correct
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Which glucose transporter is responsible for the uptake of glucose in ß cells?
Your Answer: GLUT 2
Explanation:Glucose transporter 2, also known as GLUT2 is a transmembrane carrier protein which is not insulin dependent. It is found in the liver and the pancreatic islet ß cells, where it functions as the primary glucose transporter that allows the transfer of glucose between these organs and blood.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 44
Correct
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Telomerase is active in all of the following cells, except:
Your Answer: Certain liver cells
Explanation:Telomerase is an enzyme that adds repetitive nucleotide sequences to the ends of chromosomes (telomeres), preventing their shortening during cell division. Telomerase activity is crucial for cells that divide frequently and need to maintain their telomere length for continued proliferation. These include:
- Stem cells: They have high telomerase activity to maintain their long-term proliferative capacity.
- Germ cells: These cells also have active telomerase to ensure the stability of genetic material across generations.
- Certain white blood cells: Some immune cells, particularly those that need to proliferate in response to infection, show telomerase activity.
- Certain cancer cells: Many cancer cells reactivate telomerase, which contributes to their uncontrolled growth and immortality.
However, most somatic cells, including certain liver cells, do not exhibit significant telomerase activity. While some liver cells might show low levels of telomerase activity during regeneration, it is not generally active in normal, differentiated liver cells.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 45
Correct
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What is the structure of nucleosomes?
Your Answer: Strands of double strand DNA + histones
Explanation:DNA is packed and condensed by binding to histone proteins. The double stranded DNA forms a complex with histone proteins which is called a nucleosome. There are 8 histone proteins contained in one core of nucleosome.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 46
Correct
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Portal vein receives its blood from all the following except:
Your Answer: Kidney
Explanation:The portal vein receives blood from the intestines via the superior and inferior mesenteric veins, from stomach via the gastric veins and from the spleen and pancreas via splenic vein. The kidney is supplied by the renal artery and drains into the renal vein into the inferior venacava.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 47
Correct
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Glucose is typically removed from the urine by…?
Your Answer: Secondary active transport
Explanation:Glucose, amino acids, inorganic phosphate, and some other solutes are resorbed via secondary active transport through co-transporters driven by the sodium gradient out of the nephron.
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This question is part of the following fields:
- Medicine
- Renal
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Question 48
Incorrect
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Which protein in the HIV genome is responsible for binding to the host CD4 cells?
Your Answer: gp41
Correct Answer: gp120
Explanation:HIV can infect a variety of immune cells such as CD4+ T cells, macrophages, and microglial cells. HIV-1 entry to macrophages and CD4+ T cells is mediated through interaction of the virion envelope glycoproteins (gp120) with the CD4 molecule on the target cells and also with chemokine coreceptors.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 49
Correct
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There is a measure of dispersion of a set of data from its mean. Which of following is the best term which can describe the above?
Your Answer: Standard deviation (root mean square deviation)
Explanation:Standard deviation is defined as the measure of dispersion of a set of data from its mean. It measures the absolute variability of a distribution; the higher the dispersion or variability, the greater is the standard deviation and greater will be the magnitude of the deviation of the value from their mean.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 50
Correct
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In a study, 50 out of 100 smokers developed lung cancers and 50 out of 200 non-smokers developed lung cancers. Which of the following is accurate?
Your Answer: Relative risk=2
Explanation:Relative risk = (Incidence in exposed group)/incidence in unexposed group). So in this case RR = (50/100)/(50/200) = 2.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 51
Correct
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Which of the following involving the scalp may produce alopecia (hair loss)?
Your Answer: Discoid lupus erythematosus
Explanation:Causes of hair loss include:
- Dissecting cellulitis
- Fungal infections (such as tinea capitis)
- Folliculitis
- Secondary syphilis
- Demodex folliculorum
- Lupus erythematosus (hair loss may be permanent due to scarring of the hair follicles).
Psoriasis and seborrheic dermatitis commonly involve the scalp but do not produce hair loss.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 52
Correct
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Which of the following forms an important constituent of the brush border on the microvilli of the intestinal epithelium?
Your Answer: Hydrolases
Explanation:There are certain enzymes which are part of the brush border cells including hydrolases also known as the brush border hydrolases. They perform the final step in digestion of certain nutrients.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 53
Correct
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Question 54
Incorrect
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Which heart sounds are matched correctly?
Your Answer: S1 - closure of AV valves
Correct Answer: All of the above
Explanation:In healthy adults, there are two normal heart sounds often described as a lub and a dub (or dup), that occur in sequence with each heartbeat. These are the first heart sound (S1) and second heart sound (S2), produced by the closing of the atrioventricular valves and semilunar valves, respectively. In addition to these normal sounds, a variety of other sounds may be present including heart murmurs, adventitious sounds, and gallop rhythms S3 and S4. S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. S4 when audible in an adult is called a presystolic gallop or atrial gallop. This gallop is produced by the sound of blood being forced into a stiff or hypertrophic ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 55
Correct
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The positive inotropic effect of digoxin is due to?
Your Answer: Inhibition of the sodium potassium ATPase in the myocardium
Explanation:Digitalis compounds are potent inhibitors of cellular Na+/K+-ATPase. This ion transport system moves sodium ions out of the cell and brings potassium ions into the cell. By inhibiting the Na+/K+-ATPase, cardiac glycosides cause the intracellular sodium concentration to increase. This then leads to an accumulation of intracellular calcium via the Na+/Ca++ exchange system. In the heart, increased intracellular calcium causes more calcium to be released by the sarcoplasmic reticulum, thereby making more calcium available to bind to troponin-C, which increases contractility (inotropy).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 56
Correct
-
Which cell secretes parathyroid hormone?
Your Answer: Chief cells
Explanation:Parathyroid chief cells, also known as parathyroid principal cells or parathyroid cells, are the most prevalent type of cell in the parathyroid gland and the only ones present at birth. They secrete parathyroid hormone (PTH).
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 57
Correct
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A 28 year old female with a history of psoriatic arthritis would most likely have which of the following hand conditions?
Your Answer: Nail dystrophy
Explanation:Nail dystrophy (pitting of nails, onycholysis, subungual hyperkeratosis), dactylitis, sausage shaped fingers are most commonly seen with psoriatic arthropathy. There is asymmetric joint involvement most commonly distal interphalangeal joints. Uveitis and sacroiliitis may also occur. Arthritis mutilans may occur but is very rare. Cutaneous lesions may or may not develop. When they do, its usually much after the symptoms of arthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 58
Incorrect
-
Which neuron secretes glutamate as its neurotransmitter?
Your Answer: Stellate
Correct Answer: A delta and C pain fibers
Explanation:A delta and C fibers use glutamate as their primary neurotransmitter where it acts as a fast acting localized neurotransmitter.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 59
Correct
-
Where are the cell bodies to the preganglionic neurons located?
Your Answer: Midbrain
Explanation:The cell bodies of the preganglionic neurons are located in the lateral grey column of the spinal cord and in the motor nuclei of the 3rd, 7th, 9th and 10th cranial nerves. These cranial nerves take origin from the midbrain.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 60
Correct
-
What is the primary cause of ketoacidosis in Type 1 diabetes?
Your Answer: Lipolysis
Explanation:in type 1 diabetics the lack of insulin in the bloodstream prevents glucose absorption, thereby inhibiting the production of oxaloacetate (a crucial precursor to the β-oxidation of fatty acids) through reduced levels of pyruvate (a by-product of glycolysis), and can cause unchecked ketone body production (through fatty acid metabolism or lipolysis) potentially leading to dangerous glucose and ketone levels in the blood.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 61
Incorrect
-
The predominant site in the lymph node where B lymphocytes are found is:
Your Answer: Medulla
Correct Answer: Cortex
Explanation:The cortex of the lymph node consists of the lymphoid nodules and sinusoids and posses a germinal centre from which B cells proliferate. The cortex of the lymph node predominately consists of B cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 62
Correct
-
Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:
Your Answer: Serca (sarcoplasmic or endoplasmic reticulum Ca2+ ATPase)
Explanation:Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 63
Correct
-
Which of the following can trigger parietal cell secretion?
Your Answer: Gastrin
Explanation:The three agonists of parietal cell secretion are gastrin, acetylcholine and histamine. Parietal cells are responsible for the secretion of HCl and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 64
Correct
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A 60-year-old male is under treatment with azathioprine after a renal transplant. During his review, he complains of pain and swelling over his left great toe. Investigations reveal hyperuricemia. Suspecting gout, he was started on allopurinol. Subsequently, he develops aplastic anaemia. Which of the following is the most appropriate reason for his bone marrow failure?
Your Answer: Mercaptopurine toxicity
Explanation:The cause for bone marrow suppression in this patient is most probably mercaptopurine toxicity.Azathioprine is metabolized to 6-mercaptopurine (6-MP), which itself is metabolized by xanthine oxidase. Xanthine oxidase inhibition by allopurinol leads to the accumulation of 6-MP which then precipitates bone marrow failure. This may be potentially fatal if unrecognized.Clinical presentation:Toxicity symptoms include gastrointestinal symptoms, bradycardia, hepatotoxicity, myelosuppression.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 65
Correct
-
With regard to the spleen which of the following has the correct match?
Your Answer: Periarteriolar lymphoid sheets - T lymphocytes
Explanation:The spleen consists of:Red pulp – responsible for mechanical filtration of red blood cells. Red pulp contains sinusoids, which are filled with blood, splenic cords of reticular fibers and a marginal zoneWhite pulp – responsible for active immune response through humoral and cell-mediated pathways. Composed of nodules, called Malpighian corpuscles. These are composed of: lymphoid follicles, rich in B-lymphocytes and periarteriolar lymphoid sheaths, rich in T-lymphocytes
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This question is part of the following fields:
- Haematology
- Medicine
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Question 66
Correct
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Question 67
Correct
-
The blood supply to the greater curvature of the stomach is via the:
Your Answer: Right and left gastro-epiploic arteries
Explanation:The blood supply to the greater curvature of the stomach is via the left and the right gastro-epiploic arteries branching from the splenic artery near the hilum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 68
Incorrect
-
The following cells replicate without shortening their telomeres because they express telomerase.
Your Answer: Stem cells
Correct Answer: Germ cells
Explanation:Telomerase activity is seen in germ cells and is absent in somatic cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 69
Correct
-
What is the most abundant cell type in the central nervous system called?
Your Answer: Astrocyte
Explanation:Astrocytes are the supporting cells of the central nervous system. There are two types; the fibrous type is found in the white matter and the protoplasmic type in the grey matter. They are the most abundant cell type in the CNS.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 70
Incorrect
-
A 75 year old man was brought to the clinic by his wife because lately he has lost interest in activities he previously enjoyed. His wife is worried and claims he's generally withdrawn. What would exclude depression in favour of dementia?
Your Answer: Agitation
Correct Answer: Urinary incontinence
Explanation:Urinary incontinence is not a usual symptom of depression. A depressed patient is usually capable of maintaining control of his body sphincters. In dementia, however, urinary incontinence is an important and late symptom of the disease, non-related to any urinary tract pathology. It is rather related to the cognitive impairment caused by dementia.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 71
Incorrect
-
The reticular formation occupies which area of the brain?
Your Answer: Spinal cord
Correct Answer: Medulla and midbrain
Explanation:The reticular formation is a set of interconnected nuclei that are located along the brainstem.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 72
Incorrect
-
Choose the correct statement. The cells of the liver…
Your Answer: Deaminate amino acids to form NH+4 which is excreted as ammonium salts in the urine.
Correct Answer: Help to maintain the normal blood glucose level.
Explanation:Synthesis of vitamin D3 takes place in both the liver and in the kidneys. The liver is responsible for an intermediate step and final synthesis takes place in the kidneys. Immunoglobulins are manufactured by plasma cells in respective organs where there is antigen exposure. The liver plays a major role in maintaining blood glucose levels by converting excess glucose to glycogen and converting glycogen back to glucose in time of need. Hepatocytes have enzymes that can deactivate steroid hormones.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 73
Correct
-
A 22 year old nulliparous female presents with shortness of breath. She has a history of recurrent deep vein thrombosis. Complete blood count and clotting screen reveals the following results:Hb: 12.4 g/dl Plt: 137 WBC: 7.5*109/l PT: 14 secs APTT: 46 secs Which of the following would be the most likely diagnosis?
Your Answer: Antiphospholipid syndrome
Explanation:The combination of APTT and low platelets with recurrent DVTs make antiphospholipid syndrome the most likely diagnosis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 74
Incorrect
-
Cells mediating innate immunity include:
Your Answer: B lymphocytes
Correct Answer: Natural killer cells
Explanation:Natural killer cells have features of both innate and adaptive immunity. They play an important part in defence against tumours and viruses. They are non specific and do not generate immunological memory
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This question is part of the following fields:
- Immunology
- Medicine
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Question 75
Correct
-
A 22-year-old female is brought to the emergency department by her friends following the consumption of an unknown drug whilst clubbing. Which of the following features point towards the use of ecstasy?
Your Answer: Temperature of 39.5ºC
Explanation:Hyperthermia (Temperature 39.5 C) points towards the use of ecstasy.MDMA (3,4 – methylenedioxymethamphetamine), or more commonly known as Molly or Ecstasy, is a synthetic psychoactive substance.Patients who consumed MDMA may present in a tachycardic, hypertensive, hyperthermic, and agitated state. Adverse effects, even at minor recreational doses, include increased muscle activity (such as bruxism, restless legs, and jaw clenching), hyperactivity, insomnia, difficulty concentrating and feelings of restlessness.Treatment of MDMA overdose:Emphasis should be on maintaining the airway along with the stabilization of breathing and circulation.Patients may present obtunded due to hyponatremia requiring endotracheal intubation.For the hyperthermic patient, evaporative cooling along with ice packs to the groin and axilla are beneficial.Patients who present in severe toxicity within one hour of ingestion can receive activated charcoal PO or via an NG tube. Antipyretics, such as acetaminophen, should be avoided as they have no role and can worsen an already compromised liver.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 76
Incorrect
-
Bile acids will be prevented from being absorbed by resection of which part of the gastrointestinal tract?
Your Answer: Transverse colon
Correct Answer: Ileum
Explanation:Bile acids (also called bile salts) are produced in the liver, secreted into the biliary system, stored in the gallbladder and are released after meals stimulated by cholecystokinin. They are important for the digestion and absorption of fats (lipids) in the small intestine. Usually over 95% of the bile acids are absorbed in the terminal ileum and are taken up by the liver and resecreted.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 77
Incorrect
-
Where is the majority of Mg2+ absorbed?
Your Answer: Cortical collecting duct.
Correct Answer: Thick ascending limb of loop of Henle.
Explanation:Although the majority of the filtered magnesium is reabsorbed within the ascending loop of Henle, it is now recognized that the distal tubule also plays an important role in magnesium conservation.
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This question is part of the following fields:
- Medicine
- Renal
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Question 78
Incorrect
-
The hyperpolarization phase of pacemaker cells is dominated by ____ current.
Your Answer: Mg++
Correct Answer: K+
Explanation:The hyperpolarization phase is a continuation of the repolarization phase but the membrane potential dips below the resting membrane potential. This results due to the fact that the K+ channels take a longer time to close than the Na+ channels. Hence efflux of the K+ will result in hyperpolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 79
Incorrect
-
A 23 year old male patient presents with urethritis for the last 2 weeks that has not responded to antibiotics. Lately he has developed an onset of new range of symptoms that are linked to his HLA B27 positivity. Which of the following signs is not related to Reiter's syndrome?
Your Answer: A well demarcated rash on the penis with serpiginous edges
Correct Answer: A mild fever with a generalised macular rash
Explanation:Reactive arthritis, (formerly known as Reiter’s syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondylarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously. Dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum)
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 80
Incorrect
-
Where are the principal cells found in the kidney?
Your Answer: Proximal convoluted tubule
Correct Answer: Collecting ducts
Explanation:A kidney collecting duct cell can be of two different cell types:Principal cellsIntercalated cells
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This question is part of the following fields:
- Medicine
- Renal
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Question 81
Incorrect
-
Question 82
Incorrect
-
The central veins in the liver:
Your Answer: Drain into the hepatic duct
Correct Answer: Coalesce to form the hepatic vein
Explanation:The central veins coalesce to form the hepatic vein which in turn drains into the inferior vena cava. The portal vein mainly carries blood from different parts of the GIT and is not drained to the inferior vena cava.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 83
Incorrect
-
All of the following features may suggest malignant changes in a melanocytic naevi, EXCEPT?
Your Answer: Irregularity of surface
Correct Answer: Decrease in size
Explanation:Melanocytic naevi are skin tumours produced by melanocytes. They usually present in childhood but increase during puberty. The mnemonic A-B-C-D, is used by institutions to assess for suspicion of malignancy. The letters stand for asymmetry, border, colour, and diameter. If a mole starts changing in size, colour, shape or, especially, if the border of a mole develops ragged edges or becomes larger than a pencil eraser, it would be an appropriate time to consult with a physician. Other warning signs include if it begins to crust over, bleed, itch, or become inflamed.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 84
Incorrect
-
An 87-year-old woman had to double up her dosage of morphine 60mg into 120mg twice a day, in addition to another 10mg oral Morphine 6 times a day. What is the best method of management?
Your Answer: Fentanyl patches
Correct Answer: Subcutaneous morphine infusion
Explanation:Stable dose of Morphine is essential for chronic cases of pain that are non-malignant in origin. Using the SC route avoids having to intravenously cannulate a patient and allows for a continuous infusion of drugs over a calculated period of time providing constant dosing A significant advantage is that plasma levels of a drug are much more stable, and appropriate symptom control can be achieved without the toxic effects of the peaks and troughs resulting from episodic drug administration.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 85
Incorrect
-
The nucleus tractus solitaries is medullary nucleus that processes the following inputs except:
Your Answer: Afferent impulses from the carotid baro- and chemoreceptors
Correct Answer: Sensory input from the semi-circular canal (CN VIII)
Explanation:Located in the brain stem is a series of purely sensory nuclei known as tractus solitaries. Inputs of the nucleus tractus solitaries include:Taste information from the facial nerve (anterior 2/3 of the tongue), glossopharyngeal nerve (posterior 1/3) and vagus nerve (small area on the epiglottis).Sensory information from the ear (auricular branch of the vagus nerve).Chemoreceptors and mechanoreceptors of the general visceral afferent pathway (GVA) in the carotid body via glossopharyngeal nerve, aortic bodies, and the sinoatrial node, via the vagus nerve.Chemically and mechanically sensitive neurons of the general visceral afferent pathway (GVA) with endings located in the heart, lungs, airways, gastrointestinal system, pharynx, and liver via the glossopharyngeal and vagus nerves.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 86
Incorrect
-
Stimulation of the carotid sinus results in:
Your Answer: Thirst
Correct Answer: Drop in blood pressure
Explanation:Stimulation of the carotid sinus will result in an increase in the baroreceptor discharge. This will travel via the afferent nerves to the medulla. Signals will pass through the vagus nerve to decrease the sympathetic outflow to the heart and the blood vessels. This inhibition will result in vasodilation of the blood vessels, venodilation and bradycardia hence decreasing the total peripheral resistance and lowering the blood pressure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 87
Incorrect
-
The cell membrane:
Your Answer: Membranes typically have a small number of proteins, <20% of membrane volume.
Correct Answer: Is a bilayer of amphipathic lipids
Explanation:The cell membrane consists of a bilayer of amphipathic lipids with embedded proteins. The basic function of the cell membrane is to protect the cell from its surroundings. It is selectively permeable to ions and organic molecules. The entire membrane is held together via non-covalent interaction of hydrophobic tails, however the structure is quite fluid and not fixed rigidly in place. Membranes are typically 7.5–10 nm in thickness and typically have a large content of proteins, around 50% of membrane volume.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 88
Incorrect
-
What is the function of the pro-apoptotic Bcl-2 family of proteins, Bax and Bak?
Your Answer: Stimulates the intracellular release of lysosomal contents
Correct Answer: Form permissive pores in the mitochondrial membrane
Explanation:The pro-apoptotic proteins in the BCL-2 family, including Bax and Bak, normally act on the mitochondrial membrane to promote permeabilization and release of cytochrome C and ROS, that are important signals in the apoptosis cascade. Growing evidence suggests that activated BAX and/or Bak form an oligomeric pore, MAC in the mitochondrial outer membrane. This results in the release of cytochrome c and other pro-apoptotic factors from the mitochondria, often referred to as mitochondrial outer membrane permeabilization, leading to activation of caspases.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 89
Incorrect
-
The following are synthesized in the liver EXCEPT?
Your Answer: Apoprotein B
Correct Answer: Cholecystokinin
Explanation:The liver is responsible for the mainstay of protein metabolism, synthesis as well as degradation. It is also responsible for a large part of amino acid synthesis. The liver plays a role in the production of clotting factors as well as red blood cell production. Some of the proteins synthesized by the liver include coagulation factors I (fibrinogen), II (prothrombin), V, VII, VIII, IX, X, XI, XIII, as well as protein C, protein S and antithrombin. The liver is a major site of production for thrombopoietin, a glycoprotein hormone that regulates the production of platelets by the bone marrow. The liver also produces albumin, the most abundant protein in blood serum and angiotensinogen. Cholecystokinin, previously called pancreozymin, is synthesized and secreted by enteroendocrine cells in the duodenum
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 90
Incorrect
-
Nucleic acids are split into nucleotides in the:
Your Answer: Stomach
Correct Answer: Intestine
Explanation:The pancreas is the major source for all the digestive enzymes including nucleases which split nucleic acids into nucleotides primarily in the small intestine.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 91
Incorrect
-
Which of the following statements correctly describes a function of the parasympathetic innervation of the GI tract.
Your Answer: Norepinephrine is the primary excitatory neurotransmitter
Correct Answer: Parasympathetic cholinergic activity increases the activity of intestinal smooth muscle
Explanation:The parasympathetic nerves stimulate peristalsis and relax the sphincters; they also stimulate secretion. Acetylcholine is the neurotransmitter of the parasympathetic system.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 92
Incorrect
-
Which of the following are true when it comes to tumour suppressor genes:
Your Answer: Rb gene was the first tumour suppressor gene to be found
Correct Answer: All of the options are true
Explanation:All of the above mentioned statements are true regarding tumour suppressor genes. Tumour suppressor genes generally follow the two-hit hypothesis, which implies that both alleles that code for a particular protein must be affected before an effect is manifested.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 93
Correct
-
Which statement is incorrect regarding nociceptor C fibers…
Your Answer: They are thinly myelinated
Explanation:Group C nerve fibers are unmyelinated and have a small diameter, which means they conduct impulses at a low velocity. They carry sensory information and nociception.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 94
Incorrect
-
The Plateau phase in myocyte action potentials does all of the following except:
Your Answer: It results from an Ca2+ influx
Correct Answer: It allows early reactivation of the myocytes
Explanation:The presence of the plateau in the action potential causes ventricular contraction to last as much as 15 times longer in cardiac muscle as in skeletal muscle. The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (refractory) phase prevents early reactivation of the myocytes and directly determines the strength of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 95
Incorrect
-
A 28 year old man presents to the clinic with fatigue, exertional dyspnoea, abdominal discomfort, xerophthalmia and xerostomia. Examination reveals enlargement of the parotid glands bilaterally, hepatomegaly and peripheral motor neuropathy. Lab results are negative for RF, ANA, SS-A and SS-B antibodies. What is the most likely diagnosis?
Your Answer: Sjogren's syndrome
Correct Answer: Diffuse infiltrative lymphocytic syndrome (DILS)
Explanation:The Diffuse Infiltrative Lymphocytosis Syndrome (DILS) is a rare multisystemic syndrome described in HIV-infected patients. It is characterised by CD8(+) T-cell lymphocytosis associated with a CD8(+) T-cell infiltration of multiple organs. DILS is usually seen in uncontrolled or untreated HIV infection but can also manifest itself independently of CD4(+) T-cell counts. The syndrome may present as a Sjögren-like disease that generally associates sicca signs with bilateral parotiditis, lymphadenopathy, and extra glandular organ involvement. The latter may affect the lungs, nervous system, liver, kidneys, and digestive tract. Anomalies of the respiratory system are often identified as lymphocytic interstitial pneumonia. Facial nerve palsy, aseptic meningitis or polyneuropathy are among the more frequent neurological features. Hepatic lymphocytic infiltration, lymphocytic interstitial nephropathy and digestive tract lymphocytic infiltration account for more rarely noted complications. Sicca syndrome, organomegaly and/or organ dysfunction associated with polyclonal CD8(+) T-cell organ-infiltration are greatly suggestive of DILS in people living with HIV.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 96
Incorrect
-
Question 97
Incorrect
-
Salty taste is triggered by:
Your Answer: Potassium channel
Correct Answer: Amiloride-sensitive sodium channel
Explanation:Amiloride-sensitive sodium channels also known as epithelial Na channels is a membrane bound ion channel that is selectively permeable to Na+ ions. These channels are located throughout different epithelial membranes in the body. It is found in taste receptor cells, where it plays an important role in salt taste perception. They are also located in the kidney, the lung and the colon. Hyperpolarization-activated, cyclic nucleotide-gated (HCN) voltage-gated ion channels are widely seen in the cortex, hippocampus, thalamus and brain regions that underlie the generation of both focal and generalized-onset seizures. The metabotropic glutamate receptor (mGluRs) perform a variety of functions in the central and peripheral nervous systems. They are involved in learning, memory, anxiety, and the perception of pain. Gustducin is a G protein associated with taste and gustatory system. It plays a major role in sensation of bitter, sweet and umami stimuli.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 98
Correct
-
A 50-year-old patient was started on ezetimibe, for his cholesterol a few days back. Which among the following statements is true regarding ezetimibe?
Your Answer: Its principal action is to reduce intestinal cholesterol absorption
Explanation:Ezetimibe is a cholesterol-lowering agent that acts to prevent cholesterol absorption by directly inhibiting cholesterol receptors on enterocytes.It does not affect the absorption of drugs (e.g. digoxin, thyroxine) or fat-soluble vitamins (A, D and K) as the anion-exchange resins do. It does not affect the cytochrome P450 enzyme system.The increased risk of myositis associated with the statins is not seen with ezetimibe.The most common adverse effects include headache, runny nose, and sore throat. Less common reactions include body aches, back pain, chest pain, diarrhoea, joint pain, fatigue, and weakness.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 99
Incorrect
-
With regards to the deiodinases, where would you find D1?
Your Answer: Reproductive organs
Correct Answer: Liver
Explanation:The liver produces an important amount of T3 by outer ring deiodination thanks to its elevated concentration of type I deiodinase. It can also be found in the kidney.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 100
Incorrect
-
A 45 year old man presents with fever, malaise, weight loss and myalgias that have been occurring for a month. You suspect polyarteritis nodosa and arrange for some lab investigations. Which of the following abnormality would most likely be present?
Your Answer: Thrombocytosis
Correct Answer: Elevated creatinine
Explanation:People with polyarteritis nodosa often exhibit anaemia of chronic disease. Leucocytosis and eosinophilia may also be present. ANCA is only rarely positive. As polyarteritis nodosa affects the kidneys as well, the creatinine is elevated in most cases.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 101
Incorrect
-
A 24-year-old student is brought to A&E having ingested at least 20 tablets of paracetamol 8 hours earlier. She weighs 61kg. What should her immediate management consist of?
Your Answer: Plasma paracetamol concentration estimation
Correct Answer: Intravenous N-acetylcysteine
Explanation:Activated charcoal is useful if given within one hour of the paracetamol overdose. Liver function tests, INR and prothrombin time will be normal, as liver damage may not manifest until 24 hours or more after ingestion. The antidote of choice is intravenous N-acetylcysteine, which provides complete protection against toxicity if given within 10 hours of the overdose.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 102
Incorrect
-
Choose the correct answer: The cerebrocerebellum…
Your Answer: Output to the thalamus, red nucleus and motor cortex is via the superior cerebellar peduncle
Correct Answer: All options are correct
Explanation:Cerebrocerebellum is comprised of two lateral regions, the cerebellar hemispheres and communicates with the cerebral cortex. It is principally responsible for controlling coordination of movement. Three fiber bundles carry the input and output of the cerebellum. There are three cerebellar peduncles with different connections and functions. The three are mainly, superior, middle and inferior. The superior cerebellar peduncle is also known as the “Brachium conjunctivum”. It predominantly contains efferent fibers from the cerebellar nuclei, as well as some afferents from the spinocerebellar tract. The efferent pathways include cerebellorubral, dentatothalamic, and fastigioreticular fibers. These are tracts projecting from the deep cerebellar nuclei to the thalamus and red nucleus. The middle cerebellar peduncle connects to the pontine nucleus and the dorsal spinocerebellar tracts run through the superior cerebellar peduncle
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This question is part of the following fields:
- Medicine
- Neurology
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Question 103
Incorrect
-
A 52 year old shopkeeper presents with pain in her hands. Examination reveals plaques on the extensor surfaces of her upper limbs and a telescoping deformity of both index fingers. Nails show pitting and horizontal ridging. The patient is most likely suffering from which of the following?
Your Answer: Rheumatoid arthritis
Correct Answer: Arthritis mutilans
Explanation:Arthritis mutilans is a rare (occurs in only 5% of the patients) and extremely severe form psoriatic arthritis characterized by resorption of bones and the consequent collapse of soft tissue. When this affects the hands, it can cause a phenomenon sometimes referred to as ‘telescoping fingers.’ The associated nail changes are also characteristic of arthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 104
Incorrect
-
During which phase are the 2 chromatids pulled apart at the centromere?
Your Answer: Prometaphase
Correct Answer: Anaphase
Explanation:During the prometaphase the microtubule organizing centre completely develops. The spindle fibers attach to the chromosome and the centriole. It is in the Anaphase however that the spindle fibers contract pulling the sister chromatids apart. Later in the anaphase a cleave furrow beings to forms.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 105
Incorrect
-
Which of the following would be the most appropriate treatment (leaving out the current NICE guidelines) for a 29 year old man with erythrodermic psoriasis and arthritis mutilans involving several digits of both hands?
Your Answer: Sulfasalazine
Correct Answer: Etanercept
Explanation:TNF-alpha inhibitors are known to ameliorate the symptoms and disease activity of Arthritis mutilans (a rare and severe form of psoriatic arthritis), by disabling the cytokines that are involved in inflammation and joint destruction. From the mentioned choices, this would be the most effective option. Methotrexate is the most commonly used DMARD, followed by sulfasalazine used in mild to moderate forms of psoriatic arthritis but has not shown much efficacy in arthritis mutilans. Phototherapy, narrowband UVB light therapy can be very effective in clearing skin lesions.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 106
Incorrect
-
The enzyme responsible for Telomeres to maintain their length after cell division is called:
Your Answer: None of the above telomeres shorten with all cell divisions
Correct Answer: Telomerase reverse transcriptase
Explanation:Telomeres are non-coding DNA consisting of repetitive nucleotide sequences plus proteins that are found at the end of the linear chromosomes. They maintain the integrity of the chromosomes and prevent their shortening.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 107
Incorrect
-
Which one of the following skin disorders is least commonly associated with hypothyroidism?
Your Answer: Hair loss
Correct Answer: Pretibial myxoedema
Explanation:Pretibial myxoedema is an infiltrative dermopathy, resulting as a rare complication of Graves’ disease (hyperthyroidism) and very occasionally occurs in non-thyrotoxic Graves’ disease and Hashimoto’s thyroiditis.
Hypothyroidism typically presents with symptoms such as dry skin, brittle hair, and thinning of the outer third of the eyebrows. While skin conditions like dryness and hair changes are common in hypothyroidism due to reduced metabolic activity, acne is also not typically associated with it.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 108
Incorrect
-
Inactive cellular marrow is called
Your Answer: Blue marrow
Correct Answer: Yellow marrow
Explanation:The two types of bone marrow are red marrow, which consists mainly of hematopoietic tissue, and yellow marrow, which is mainly made up of fat cells.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 109
Correct
-
In the absence of insulin:
Your Answer: Glucose uptake by most of the brain is normal
Explanation:Although it is known that insulin levels affect glucose uptake, oxidation and storage in peripheral tissues, its role in the brain isn’t as clear. However, studies have shown that bulk brain glucose uptake isn’t affected by insulin. Glucose transport into the neurons is GLUT3 dependent, and its transport into glia and brain endothelial cells rely on GLUT1. Insulin isn’t necessary for GLUT1 or GLUT3, which explains why brain glucose uptake isn’t affected by insulin levels.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 110
Incorrect
-
A 23-year-old female known with schizophrenia is being reviewed in the emergency department. Her mother claims that she has been 'staring' for the past few hours but has now developed abnormal head movements and has gone 'cross-eyed'. On examination, the patient's neck is extended and positioned to the right. Her eyes are deviated upwards and are slightly converged. Given the likely diagnosis, what is the most appropriate treatment?
Your Answer: Dopamine
Correct Answer: Procyclidine
Explanation:The most probable diagnosis in this patient is an oculogyric crisis, that is most appropriately managed with procyclidine or benztropine (antimuscarinic). An oculogyric crisis is a dystonic reaction to certain drugs or medical conditions.Features include:Restlessness, agitationInvoluntary upward deviation of the eyesCauses:PhenothiazinesHaloperidolMetoclopramidePostencephalitic Parkinson’s diseaseManagement:Intravenous antimuscarinic agents like benztropine or procyclidine, alternatively diphenhydramine or ethopropazine maybe used.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 111
Incorrect
-
Restriction Enzymes...
Your Answer: Cut mitochondrial sequences at specific sites
Correct Answer: Cut DNA sequences at specific sites
Explanation:Restriction endonucleases are enzymes that recognise short sequences of double stranded DNA and cut them at specific nucleotide points or sequences. These sequences differ for different restriction endonucleases.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 112
Incorrect
-
All valves are closed in which phase of the cardiac cycle?
Your Answer: Ejection phase
Correct Answer: Isovolumetric relaxation
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 113
Incorrect
-
The telomerase is capable of adding several more repeats of telomeres at which end of the guanosine rich region.
Your Answer: 5th end
Correct Answer: 3rd end
Explanation:Telomerase is a reverse transcriptase that uses the RNA template to synthesize DNA in the 5th-3rd direction resulting in extension of the 3rd end and then translocates it to the newly synthesized end. The GT rich strand is thus elongated.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 114
Incorrect
-
Which of the following is not true regarding mitochondrial chromosome disorders?
Your Answer: Most mitochondrial diseases are myopathies and neuropathies with a maternal pattern of inheritance
Correct Answer: Because mitochondrial chromosomes have no introns in their genes, any point mutation has a low likelihood of having an effect.
Explanation:Any point mutation in any part of the mitochondrial DNA will lead to a mutated mitochondria and will likewise have its ill effect on the body.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 115
Incorrect
-
Which statement about antithrombin III is true?
Your Answer: It inactivates factors V and VIII
Correct Answer: It inhibits particularly factor II and X
Explanation:Antithrombin inactivates its physiological target enzymes, Thrombin (Factor II), Factor Xa and Factor IXa. ATIII binds to thrombin and then forms the thrombin-anti thrombin complex or TAT complex. This is a major natural pathway of anticoagulation. This binding of thrombin to AT is greatly enhanced in the presence of heparin.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 116
Incorrect
-
A lesion that interrupts one optic nerve causes blindness:
Your Answer: Bilateral, opposite sites of visual fields, in half of the visual fields (heteronymous hemianopia)
Correct Answer: In the eye on the same side as the optic nerve
Explanation:The optic nerve on each side contains medial and lateral fibers originating from the retina. Medial fibers cross at the optic chiasm and become the optic tract ending in the visual cortex of the occipital lobe. If there is a lesion interrupting the “optic nerve” on one side, the same side eye will be completely blind.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 117
Incorrect
-
A 31 year old female with systemic lupus erythematosus wants to know if she has any predisposing factors for the disease. Which of the following carries the greatest risk of developing SLE?
Your Answer: Positive HLA–DR2
Correct Answer: Monozygotic twin
Explanation:An overall concordance rate in monozygotic twins was documented to be 25% as compared to dizygotic twins with 3%. First degree relatives have a chance of around 3% of developing the disease. Caucasians show an increase frequency of HLA-B8. The Japanese lupus patients had a stronger association with HLA-DR2.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 118
Incorrect
-
Glucose absorption in the small intestine is coupled with which of the following electrolytes?
Your Answer: Mg
Correct Answer: Na
Explanation:Sodium-glucose linked transporter are family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine and absorbs glucose via cotransport of Na+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 119
Incorrect
-
Which lipoprotein contains the most cholesterol esters?
Your Answer: HDL
Correct Answer: LDL
Explanation:LDL and HDL transport both dietary and endogenous cholesterol in the plasma, but LDL is the main transporter of cholesterol and cholesteryl esters.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 120
Incorrect
-
The axons of which neurons serve as the only output from the cerebellar cortex?
Your Answer: Stellate
Correct Answer: Purkinje
Explanation:The cerebellar cortex consist of 3 layers. The molecular layer, the granule cell layer and the Purkinje cell layer in the middle. The Purkinje cells project into the deep cerebellar nuclei. They are the only output cells of the cerebellar cortex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 121
Correct
-
The celiac trunk consists of which arteries?
Your Answer: Left gastric, common hepatic, splenic
Explanation:The celiac trunk is the first major branch of the abdominal aorta. It is 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12). There are three main divisions of the celiac artery:- left gastric artery- common hepatic artery- splenic artery
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 122
Incorrect
-
What is the average life span of red blood cells?
Your Answer: 7 months
Correct Answer: 4 months
Explanation:Approximately 2.4 million new erythrocytes are produced per second in human adults. The cells develop in the bone marrow and circulate for about 100–120 days (4 months) in the body before their components are recycled by macrophages.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 123
Incorrect
-
A 45-year-old woman has been diagnosed with T1N1M1 malignancy in the left breast, with metastases detectable in the lower thoracic vertebrae and the left lung. Before the initiation of treatment of this patient with trastuzumab, which is the most important investigation to perform?
Your Answer: Glucose tolerance test
Correct Answer: Echo
Explanation:Before the initiation of trastuzumab, an echocardiography is a must to rule out any pre-existing cardiac abnormalities as trastuzumab is cardiotoxic.Trastuzumab (Herceptin) is a monoclonal antibody directed against the HER2/neu receptor. It is used mainly in metastatic breast cancer although some patients with early disease are now also given trastuzumab.Adverse effects include:Flu-like symptoms and diarrhoea are common.Cardiotoxicity: – Risk increases when anthracyclines are used concomitantly. – Trastuzumab-induced cardiac dysfunctions are regarded as less severe and largely reversible because primary cardiomyocyte do not show ultrastructure changes unlike those associated with anthracycline-induced cardiotoxicity. – Primary myocyte injury does not occur in patients who were treated with trastuzumab.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 124
Incorrect
-
The Sinoatrial node in the majority of people is supplied by the?
Your Answer: Left coronary artery
Correct Answer: Right coronary artery
Explanation:In 60% of people, the SA node is supplied by the right coronary artery branch and in 40% of the people by the left coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 125
Incorrect
-
Which part of the cerebellum is primarily responsible for interacting with the motor cortex and planning and programming movements?
Your Answer: Spinocerebellum
Correct Answer: Cerebrocerebellum
Explanation:The cerebrocerebellum is the largest functional subdivision of the cerebellum, comprising of the lateral hemispheres and the dentate nuclei. It is involved in the planning and timing of movements, and in the cognitive functions of the cerebellum.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 126
Incorrect
-
Which of the following statements is true of the beta- lactams:
Your Answer: Acts by directly disrupting bacterial cell walls
Correct Answer: Co-amoxiclav is more likely to cause obstructive jaundice than amoxicillin
Explanation:β-lactam antibiotics are a class of broad-spectrum antibiotics, consisting of all antibiotic agents that contain a β-lactam ring in their molecular structures. This includes penicillin derivatives (penams), cephalosporins (cephems), monobactams, and carbapenems. Most β-lactam antibiotics work by inhibiting cell wall biosynthesis in the bacterial organism and are the most widely used group of antibiotics. Bacteria often develop resistance to β-lactam antibiotics by synthesizing a β-lactamase, an enzyme that attacks the β-lactam ring. To overcome this resistance, β-lactam antibiotics are often given with β-lactamase inhibitors such as clavulanic acid. Immunologically mediated adverse reactions to any β-lactam antibiotic may occur in up to 10% of patients receiving that agent (a small fraction of which are truly IgE-mediated allergic reactions). Rarely, cholestatic jaundice has been associated with Co-amoxiclav (amoxicillin/clavulanic acid). The reaction may occur up to several weeks after treatment has stopped, and usually takes weeks to resolve. It is more frequent in men, older people, and those who have taken long courses of treatment; the estimated overall incidence is one in 100,000 exposures.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
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Question 127
Incorrect
-
Choose the standard method for comparing distributions in data sets (such as between the expected frequency of an event and the observed frequency of an event) from the list of options.
Your Answer: Mean
Correct Answer: Chi squared (X²) test
Explanation:The Chi-squared test evaluates if two variables are related. The other statistical tests mentioned do not perform this function.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 128
Correct
-
The main reason for the prolonged effect of the withdrawal reflex is:
Your Answer: Multiple connections between afferent and efferent neurons
Explanation:The withdrawal reflex is a spinal reflex that protects the body from harmful stimuli. Spinal reflexes are mostly monosynaptic and are mediated by a simple reflex arc. Withdrawal reflex is mediated by a polysynaptic reflex resulting in stimulation of many motor neurons in order to establish a quick and prolonged response.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 129
Incorrect
-
Which of the following statements is true about chromosomes?
Your Answer: Are structures containing one linear molecule of DNA that is wound around histones into small units called nucleosomes, which are further wound up to make the chromosome
Correct Answer: All of the above
Explanation:All of the above mentioned statements are true regarding chromosomes.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 130
Incorrect
-
According to Starling's law of the heart:
Your Answer: Cardiac output is increased when the sympathetic nerves are stimulated
Correct Answer: The extent of the preload is proportional to the end-diastolic volume
Explanation:Frank starlings law describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increased venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and the development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relationship is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 131
Incorrect
-
The structure of haemoglobin A in adults includes
Your Answer: Haem, globin polypeptide chains α and υ
Correct Answer: Haem, globin polypeptide chains α and β
Explanation:Haemoglobin A (HbA), also known as adult haemoglobin or α2β2, is the most common human haemoglobin tetramer, comprising over 97% of the total red blood cell haemoglobin. It consists of two alpha chains and two beta chains.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 132
Incorrect
-
An 81 year old male patient was admitted after an ischaemic stroke. Physical examination reveals left hemiparesis. How would you classify this hemiparesis based on the WHO International Classification of Functioning, Disability and Health?
Your Answer: Activity limitation
Correct Answer: Impairment of body function
Explanation:Symptoms and signs are classified as ‘impairment of body function’. The types of impairment classified as ‘activity limitation’ include difficulties that a patient may have in executing certain activities. The type of impairment classified as ‘participation restriction’ are problems a patient may have in social roles. The type of impairment classified as ‘pathology’ would be the diagnosis/disease. Right total anterior circulation infarct relates to the Oxford Bamford classification for stroke.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 133
Incorrect
-
Cholinergic nerves from the vagus innervate the SA and AV nodes via which receptor in the heart?
Your Answer: B3 receptor
Correct Answer: M2 receptor
Explanation:M2 receptor is found in the heart. M3 and M4 are associated with smooth muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 134
Correct
-
In which stage of mitosis are the chromosomes most obvious or prominent?
Your Answer: Metaphase
Explanation:Prophase begins when the nucleus envelope disintegrates and the chromosomes start to condense. The chromosomes consist of two sister chromatids that are joined at a constriction known as centromere. When the cell reaches the metaphase the chromosomes are completely condensed and ready to align on the equatorial plate.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 135
Incorrect
-
Regarding taste threshold and intensity discrimination:
Your Answer: 60% change in concentration of substance tasted is necessary before an intensity difference can be detected
Correct Answer: 30% change in concentration of substance tasted is necessary before an intensity difference can be detected
Explanation:The ability of humans to differentiate differences in intensity of taste is poor. A 30% change in the concentration of the substance being tasted is required before an intensity difference is perceived.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 136
Incorrect
-
Dicrotic notch is produced by which valves?
Your Answer: Pulmonary
Correct Answer: Aortic
Explanation:The graph of aortic pressure throughout the cardiac cycle displays a small dip (the incisure or dicrotic notch) which coincides with the aortic valve closure. The dip in the graph is immediately followed by a brief rise (the dicrotic wave) then gradual decline.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 137
Incorrect
-
Which serotonergic receptor is associated with vomiting?
Your Answer: 5ht5
Correct Answer: 5ht3
Explanation:5ht3 is a receptor strongly associated with vomiting, present in vagal afferents, the solitary tract nucleus (STN), and the area posterior. For this reason, 5ht3 antagonists are commonly used as antiemetic drugs. They include ondansetron, tropisetron, and granisetron.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 138
Incorrect
-
Which of the following phases in depolarization and repolarization of cardiac muscle cells are caused by the inactivation of Na+ channels?
Your Answer: Phase 0 : rapid depolarization
Correct Answer: Phase 1 : rapid repolarization
Explanation:Phase 0 is caused by the sodium current. Voltage gated sodium channels open leading to the influx of sodium into the cardiac muscle cell. Phase 1 is the rapid transient repolarization phase which is caused by the inactivation of the voltage gated sodium channels and opening of the voltage gated potassium channels along with opening of the slow calcium channels. Phase 2 which is the plateau is caused by opening of the slow calcium channels. Phase 4 is caused by closing of the slow calcium channels and opening of the potassium channels leading to efflux of potassium leading to the establishment of the resting membrane potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 139
Correct
-
In a knockout mouse model the process used to combine the new DNA sequence and the stem cells is known as:
Your Answer: Insertion
Explanation:Chimerisation is also known as the formation of recombinant DNA. When a foreign DNA sequence is inserted into a plasmid or other DNA sequence, this process is known as insertion.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 140
Incorrect
-
Regarding cardiac muscle contractility, the afterload refers to:
Your Answer: The degree of myocardial stretch before contraction
Correct Answer: The resistance against which blood is expected
Explanation:The afterload for the left ventricle is the aortic pressure. Hence it is this pressure that offers resistance against which the blood is to be expelled from the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 141
Incorrect
-
The tectum as part of the Midbrain contains which structure important in visual reflexes.
Your Answer: Red nucleus
Correct Answer: Superior colliculus
Explanation:The tectum is a part of the midbrain, specifically, the dorsal part of the midbrain. The tectum consists of the superior and inferior colliculi. The superior colliculus is involved in preliminary visual processing and control of eye movement.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 142
Incorrect
-
An 86 year old woman accidentally inhaled her hearing aid due to her advanced Alzheimer's dementia. Upon clinical examination, her respiratory rate is found to be 35, and thus a bronchoscopy is recommended. According to which of the following would you obtain consent for this patient?
Your Answer: The doctor will be able to consent for the patient
Correct Answer: The procedure does not require a written consent
Explanation:This is an emergency case regarding a patient with impaired cognitive functioning. This is why the procedure does not require a written consent. In any other case where the patient has a normal mental capacity, the consent would be obtained as an informed written consent. In this case however, the suggested procedure is almost a matter of life and death, the doctor being required to act on behalf of the patient to her optimal advantage. Under English law no other person can consent to treatment on behalf of an adult, though it is desirable that next of kin are consulted before treating an adult without consent. Recent legislation gives legal authority to people appointed by the patient, or by the state, or a relative or carer, to consent (or refuse) on behalf of the patient. A mini-mental score may not adequately identify those unable to give consent.
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This question is part of the following fields:
- Geriatrics
- Medicine
-
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Question 143
Incorrect
-
Which is the primary lymphoid organ?
Your Answer: Tonsils
Correct Answer: Thymus
Explanation:Lymphoid organs consist of lymph nodes, the thymus, spleen and tonsils. The thymus is the primary lymphoid organ as it is the organ in which the T cells mature.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 144
Correct
-
The main source of nutrients in the liver is via the
Your Answer: Portal vein
Explanation:The portal vein or hepatic portal vein is a blood vessel that carries blood from the gastrointestinal tract and spleen to the liver. This blood is rich in nutrients that have been extracted from food, and the liver processes these nutrients; it also filters toxins that may have been ingested with the food. 75% of total liver blood flow is through the portal vein, with the remainder coming from the hepatic artery proper.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
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Question 145
Incorrect
-
Cholecystokinin causes the pancreas to
Your Answer: Secrete large amounts of acidic pancreatic juice
Correct Answer: Produce pancreatic juice rich in enzymes
Explanation:Cholecystokinin (CCK) mediates digestion in the small intestine by inhibiting gastric emptying and decreasing gastric acid secretion. It stimulates the acinar cells of the pancreas to release a juice rich in pancreatic digestive enzymes, hence the old name pancreozymin. Together these enzymes catalyse the digestion of fat, protein, and carbohydrates.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 146
Incorrect
-
Alveolar epithelial cells:
Your Answer: Type 2 covers a greater part of the surface
Correct Answer: Type 2 represent 60% of the cells
Explanation:Type I alveolar cells are squamous (giving more surface area to each cell) and cover approximately 90–95% of the alveolar surface. Type I cells are involved in the process of gas exchange between the alveoli and blood. Type II alveolar cells cover a small fraction of the alveolar surface area. Their function is of major importance in the secretion of pulmonary surfactant, which decreases the surface tension within the alveoli. They are also capable of cellular division, giving rise to more type I alveolar cells when the lung tissue is damaged. These cells are granular and roughly cuboidal. Type II alveolar cells are typically found at the blood-air barrier. Although they only comprise <5% of the alveolar surface, they are relatively numerous (60% of alveolar epithelial cells).
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 147
Incorrect
-
A cohort study is being designed to look at the relationship between smoking and prostate cancer. What is the usual outcome measure in a cohort study?
Your Answer: Odds ratio
Correct Answer: Relative risk
Explanation:A cohort study is a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as birth or graduation), performing a cross-section at intervals through time. The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Relative risk is used in the statistical analysis of the data of experimental, cohort and cross-sectional studies, to estimate the strength of the association between treatments or risk factors, and outcomes.
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This question is part of the following fields:
- Medicine
- Research Skills
-
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Question 148
Incorrect
-
Coronary blood flow occurs in?
Your Answer: Corresponds with the QRS complex on ECG
Correct Answer: Diastole
Explanation:Coronary arteries are unique in that they fill during diastole, when not occluded by valve cusps nor compressed by myocardial contraction).
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 149
Incorrect
-
The cavernous sinus is?
Your Answer: Medial to the body of the mastoid
Correct Answer: Lateral to the body of the sphenoid
Explanation:It is a venous sinus which creates a cavity called the lateral sellar compartment bordered by the temporal bone and the sphenoid bone. There are 2 on either side. It is about 1cm wide and extends from the posterior aspect of the orbit to the petrous part of the temporal bone. They sit on either side or lateral to the sphenoid bone.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 150
Correct
-
Empagliflozin was found to reduce the risk of cardiovascular deaths, non-fatal myocardial infarction and non-fatal stroke when added to standard treatment plans in patients with type 2 diabetes mellitus. This information was shared in 2015 by The New England Journal of Medicine and the results were expressed per 1000 patient years. In fact, empagliflozin had an event rate of 37.3/1000 patient years and placebo an event rate of 43.9/1000 patient years. How many patients who are at high cardiovascular risk need to be treated with empagliflozin to prevent a cardiovascular death, a non-fatal myocardial infarction or a non-fatal stroke?
Your Answer: 150
Explanation:The number needed to treat (NNT) is an absolute effect measure that has been used to assess beneficial and harmful effects of medical interventions. In this case the NNT can be calculated as follows: NNT = 1/ Absolute risk reduction (ARR). ARR=(Control event rate expressed per 1000 patient years) – (Experimental event rate expressed per 1000 patient years) = 43.9-37.3 = 6.6/1000 patient yearsNNT=(Patient years)/ARR = 1000/ 6.6 = 151.5. The closest to 151.5 is 150, thus it is the correct answer.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 151
Incorrect
-
Which of the following is an incorrect statement regarding the structure of DNA?
Your Answer: There are only four possible pairs of nucleotides.(ta, at, gc and cg)
Correct Answer: The two strands of DNA are held together by cysteine bonds.
Explanation:The two strands of DNA are held together by hydrogen bonds formed between the nucleotide bases.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 152
Incorrect
-
Approximately what percentage of the world is infected with tuberculosis:
Your Answer: 10%
Correct Answer: 25%
Explanation:The WHO report states that about one-quarter of the world’s population is infected with Mycobacterium tuberculosis, the bacterium that causes tuberculosis. This means approximately 25% of people globally have latent TB infection, which can potentially progress to active TB disease.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
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Question 153
Correct
-
With regard to X-linked disorders which of the following are true:
Your Answer: X linked recessive disorders usually present in males and only very rarely present in homozygous females
Explanation:X linked disorders are more common in males as they only need one mutated copy of the X chromosome to manifest the disease with full severity while the females need two X chromosomes to manifest the disease, even with one defected X chromosome the severity is less than that seen in males.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 154
Incorrect
-
Which of the following types of reactions are a part of the phase II metabolism of a drug?
Your Answer: Reduction
Correct Answer: Conjugation
Explanation:Drug metabolism can be broadly classified into:Phase I (functionalization) reactions: also termed non-synthetic reactions, they include oxidation, reduction, hydrolysis, cyclization and de-cyclization. The most common and vital reactions are oxidation reactions. (Of the given enzymes only Alcohol dehydrogenase is involved in phase I drug metabolism. Succinate dehydrogenase, is a vital enzyme involved in the Kreb’s cycle and the mitochondrial electron transport chain). They are mainly catalysed by Cytochrome P-450 enzyme.Phase II (conjugation) reactions: occur following phase I reactions, they include reactions: glucuronidation and sulphate conjugation, etc. They are mostly catalysed by UDP-glucuronosyltransferase enzyme. Other phase II enzymes include: sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 155
Correct
-
Which enzyme is deficient in the inborn error of metabolism called galactosemia?
Your Answer: Galactose-1-phosphate uridyl transferase
Explanation:Galactosaemia is a rare genetic autosomal recessive metabolic disorder. Lactose is broken down by the enzyme lactase into glucose and galactose. In individuals with galactosemia, the enzymes needed for further metabolism of galactose (Galactose-1-phosphate uridyltransferase) are severely diminished or missing entirely, leading to toxic levels of galactose 1-phosphate in various tissues.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 156
Correct
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Concerning S3, which of the following statements is INCORRECT?
Your Answer: Coincide with atrial contraction
Explanation:A third heart sound also called a ventricular gallop occurs at the beginning of diastole after S2 and is lower in pitch than S1 or S2 as it is not of valvular origin. The third heart sound is benign in youth, some trained athletes, and sometimes in pregnancy but if it re-emerges later in life it may signal cardiac problems, such as a failing left ventricle as in dilated congestive heart failure (CHF). S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. It may also be a result of tensing of the chordae tendineae during rapid filling and expansion of the ventricle. In other words, an S3 heart sound indicates increased volume of blood within the ventricle. An S3 heart sound is best heard with the bell-side of the stethoscope (used for lower frequency sounds). A left-sided S3 is best heard in the left lateral decubitus position and at the apex of the heart, which is normally located in the 5th left intercostal space at the midclavicular line. A right-sided S3 is best heard at the lower-left sternal border. The way to distinguish between a left and right-sided S3 is to observe whether it increases in intensity with inhalation or exhalation. A right-sided S3 will increase on inhalation, while a left-sided S3 will increase on exhalation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 157
Correct
-
On a mountain the atmospheric pressure is 700 mmHg and the humidity close to zero, the partial pressure of oxygen is:
Your Answer: 147 mmHg
Explanation:Natural air includes approximately 21% of oxygen. If humidity is zero, the partial pressure of oxygen is 700 × 21% = 147 mmHg
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 158
Incorrect
-
What microscopic changes are visible in an active thyroid gland?
Your Answer: Follicle lining cells are flat.
Correct Answer: Follicle lining cells are cuboid or columnar.
Explanation:Active follicles are lined by cuboidal or columnar cells; this is because active follicles are smaller and have less colloid. Their cells are tall because they are actively secreting hormones, whereas older follicles have a flat epithelium and are filled with more colloid.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 159
Incorrect
-
Where is most of the filtered sodium reabsorbed?
Your Answer: Thick ascending loop of Henle
Correct Answer: Proximal tubule
Explanation:Renal reabsorption of sodium (Na+) is a part of renal physiology. It uses Na-H antiport, Na-glucose symport, sodium ion channels (minor). It is stimulated by angiotensin II and aldosterone, and inhibited by atrial natriuretic peptide. Most of the reabsorption (65%) occurs in the proximal tubule.
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This question is part of the following fields:
- Medicine
- Renal
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Question 160
Incorrect
-
A 40-year-old man is admitted to the Emergency Department in a confused state. He tells you that he consumed two bottles of antifreeze. On examination, his pulse is 120 bpm and blood pressure is 140/90 mmHg. An arterial blood gas analysis shows uncompensated metabolic acidosis. He is transferred to the high dependency unit and ethanol is given via a nasogastric tube. How does ethanol help this patient?
Your Answer: Binds to glycolaldehyde
Correct Answer: Competes with ethylene glycol for alcohol dehydrogenase
Explanation:Ethanol competes with ethylene glycol for alcohol dehydrogenase and thus, helps manage a patient with ethylene glycol toxicity.Ethylene glycol is a type of alcohol used as a coolant or antifreezeFeatures of toxicity are divided into 3 stages:Stage 1: (30 min to 12 hours after exposure) Symptoms similar to alcohol intoxication: confusion, slurred speech, dizziness (CNS depression)Stage 2: (12 – 48 hours after exposure) Metabolic acidosis with a high anion gap and high osmolar gap. Also tachycardia, hypertensionStage 3: (24 – 72 hours after exposure) Acute renal failureManagement has changed in recent times:Fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol.Ethanol has been used for many years works by competing with ethylene glycol for the enzyme alcohol dehydrogenase this limits the formation of toxic metabolites (e.g. glycolaldehyde and glycolic acid) which are responsible for the hemodynamic/metabolic features of poisoning.Haemodialysis has a role in refractory cases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 161
Correct
-
A 72 year old female, known with rheumatoid arthritis for last 17 years, presents with recurrent attacks of red eyes with a sensation of grittiness. Which of the following is most likely cause of the red eyes?
Your Answer: keratoconjunctivitis sicca
Explanation:Rheumatoid arthritis is an inflammatory systemic disease associated with some extraarticular manifestations. Keratoconjunctivitis sicca, episcleritis, scleritis, corneal changes, and retinal vasculitis are the most common ocular complications among extraarticular manifestations of RA. The overall prevalence of keratoconjunctivitis sicca also known as dry eye syndrome among patients of RA is 21.2% and is the most common with sense of grittiness in the eyes.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 162
Incorrect
-
A patient who has mild benign prostatic hyperplasia has been advised to take finasteride.The mechanism of action of this drug involves inhibition of the production of which of the following androgens?
Your Answer: Dehydroepiandrosterone
Correct Answer: Dihydrotestosterone
Explanation:Finasteride inhibits the formation of dihydrotestosterone.Finasteride is a 5α-reductase inhibitor and thus, inhibits the conversion of testosterone to dihydrotestosterone (DHT). DHT is much more active than testosterone and binds more avidly to cytoplasmic receptors. DHT stimulates prostate growth and may be responsible for benign prostatic hyperplasia in the elderly. Thus, finasteride can cause a reduction in prostatic volume and help in managing a patient with benign prostatic hyperplasia.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 163
Incorrect
-
Which one of the following leads to decreased prolactin levels?
Your Answer: Oestrogens
Correct Answer: Dopamine
Explanation:Dopamine has an important effect on the regulation of prolactin secretion. Dopamine binds to type-2 dopamine receptors of the lactotroph cells that are functionally linked to membrane channels and G proteins and suppresses the high secretory activity of the pituitary lactotrophs.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 164
Correct
-
A 68 year old man presents with acute symptoms of gout on his first metatarsophalangeal joint. Which option best explains the underlying mechanism of gout?
Your Answer: Decreased renal excretion of uric acid
Explanation:Primary gout is related more often to underexcretion of uric acid or overproduction.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 165
Incorrect
-
Endothelial cells produce the following substance(s):
Your Answer: Endothelins
Correct Answer: All of the above
Explanation:Endothelial cells produce thromboxane, prostacyclins, nitric oxides, endothelins, IL-1 and TNF.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 166
Incorrect
-
90% of erythropoietin necessary for haemopoesis is produced by the kidneys, the remainder is formed in the?
Your Answer: Bone marrow
Correct Answer: Liver
Explanation:Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 167
Incorrect
-
The residual cleft of the intermediate lobe of the pituitary is lined by follicles resembling which human gland?
Your Answer: Parathyroid
Correct Answer: Thyroid
Explanation:The cells located between the two main pituitary lobes form what is known as the intermediate pituitary. This area secretes melanocyte-stimulating hormone and it is only a few cell layers thick. It is rich in follicles filled with colloid, and lined by basophilic cells. This configuration resembles that of another important gland: the thyroid.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 168
Correct
-
The only APCs that can activate naive T lymphocytes are:
Your Answer: Dendric cells
Explanation:Only professional antigen-presenting cells (macrophages, B lymphocytes, and dendritic cells) are able to activate a resting helper T-cell when the matching antigen is presented. However, macrophages and B cells can only activate memory T cells whereas dendritic cells can activate both memory and naive T cells, and are the most potent of all the antigen-presenting cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 169
Correct
-
Under normal conditions (where n represents the number of chromosome pairs), just before mitosis begins, how many chromosomes are contained in the nucleus of each somatic cell:
Your Answer: 4n
Explanation:In a normal somatic cell there are 2n chromosome but in a replicating cell just before mitosis the chromosomes duplicate but are still joined via the centrosome. Thus there are 4n chromosomes. After completion of mitosis the number goes back to 2n.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 170
Incorrect
-
Major supplies of glycogen are found in ….
Your Answer: Liver and adipose tissues
Correct Answer: Liver and skeletal muscle
Explanation:The two major sites of glycogen storage are the liver and skeletal muscle. The concentration of glycogen is higher in the liver than in muscle however more glycogen is stored in skeletal muscle due to its greater mass.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 171
Correct
-
How does pregnancy affect the cardiac output of a patient?
Your Answer: Increased cardiac output due to increase in heart rate and stroke volume
Explanation:Cardiac Output increases to a similar degree as the blood volume. During the first trimester cardiac output is 30-40% higher than in the non-pregnant state. Steady rises are shown on Doppler echocardiography, from an average of 6.7 litres/minute at 8-11 weeks to about 8.7 litres/minute flow at 36-39 weeks; they are due, primarily, to an increase in stroke volume (35%) and, to a lesser extent, to a more rapid heart rate (15%). There is a steady reduction in systemic vascular resistance (SVR) which contributes towards the hyperdynamic circulation observed in pregnancy
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 172
Incorrect
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Question 173
Incorrect
-
Which statement is incorrect?
Your Answer: Poly a tail is not translated and is preceded by a stop codon, UAA, UAG, UGA.
Correct Answer: Translation begins when the triplet (UGA) encoding for methionine is encountered.
Explanation:Translation being when the codon for methionine is encountered which is AUG not UGA. This process is known as initiation. All the other options are correct.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 174
Incorrect
-
A 39-year-old accountant with long-standing gastro-oesophageal reflux disease is reviewed in clinic. He has recently switched from ranitidine to omeprazole. What is the main benefit of omeprazole compared to ranitidine?
Your Answer: Decreased post-prandial acid production
Correct Answer: Irreversible blockade of H+/K+ ATPase
Explanation:Proton pump inhibitors can reduce gastric acid secretion by up to 99%. Acid production resumes following the normal renewal of gastric parietal cells.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 175
Incorrect
-
Which of the following intercellular connections is important in endothelial barrier function?
Your Answer: Zonula adherens
Correct Answer: Tight junctions
Explanation:Tight junctions surround the apical margins of the epithelial cells such as in the intestinal mucosa and the choroid plexus. They are also important to the endothelial barrier function. They are made up of ridges that adhere to each other strongly at the cell junction, obliterating the space completely between the cells.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 176
Incorrect
-
The pyloric sphincter is largely made up of thickening of
Your Answer: Outer longitudinal layer
Correct Answer: The circular muscle layer
Explanation:The pyloric sphincter, or valve, is a strong ring of smooth muscle (circular muscle layer) at the end of the pyloric canal which lets food pass from the stomach to the duodenum. It controls the outflow of gastric contents into the duodenum. It receives sympathetic innervation from the celiac ganglion.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 177
Incorrect
-
The HIV virus:
Your Answer: Glycoprotein p41 binds to the chemokine receptors
Correct Answer: P24 is a core protein
Explanation:HIV is different in structure from other retroviruses. It is roughly spherical with a diameter of about 120 nm, around 60 times smaller than a red blood cell. It is composed of two copies of positive single-stranded RNA that codes for the virus’s nine genes enclosed by a conical capsid composed of 2,000 copies of the viral protein p24. The single-stranded RNA is tightly bound to nucleocapsid proteins, p7, and enzymes needed for the development of the virion such as reverse transcriptase, proteases, ribonuclease and integrase. A matrix composed of the viral protein p17 surrounds the capsid ensuring the integrity of the virion particle. Reverse transcriptase copies the viral single stranded RNA genome into a double-stranded viral DNA.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 178
Incorrect
-
A 65-year-old man presents to you three weeks after initiating metformin for type 2 diabetes mellitus. His body mass index is 27.5 kg/m^2. At a dose of 500mg TDS the patient has experienced significant diarrhoea. Even on reducing the dose to 500mg BD his symptoms persisted. What is the most appropriate next step in this patient?
Your Answer: Switch to pioglitazone 15mg od
Correct Answer: Start modified release metformin 500mg od with evening meal
Explanation:Here, the patient seems to be intolerant to standard metformin. In such cases, modified-release preparations is considered as the most appropriate next step. There is some evidence that these produce fewer gastrointestinal side-effects in patients intolerant of standard-release metformin.Metformin is a biguanide and reduces blood glucose levels by decreasing the production of glucose in the liver, decreasing intestinal absorption and increasing insulin sensitivity. Metformin decreases both the basal and postprandial blood glucose.Other uses: In Polycystic Ovarian Syndrome (PCOS), Metformin decreases insulin levels, which then decreases luteinizing hormone and androgen levels. Thus acting to normalize the menstruation cycle.Note:Metformin is contraindicated in patients with severe renal dysfunction, which is defined as a glomerular filtration rate (GFR) less than 30 ml/min/1.732m2. Metformin overdose has been associated with hypoglycaemia and lactic acidosis, for this reason, it has a black box warning for lactic acidosis.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 179
Incorrect
-
Anti-gastroesophageal reflux mechanisms include the following except:
Your Answer: The sling fibers of the stomach
Correct Answer: Peristaltic movements of the oesophagus
Explanation:The lower oesophageal sphincter contracts preventing reflux of acid into the oesophagus. The sling muscles of the stomach, the crura of the diaphragm and the phreno-oesophageal ligament all play an important role in constricting the lower portion of the oesophagus and preventing reflux. Peristaltic movements do not stop the acid reflux.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 180
Correct
-
A 24-year-old women presents following an overdose. Which one of the following would suggest anticholinergic syndrome?
Your Answer: Mydriasis occurs
Explanation:Anticholinergic syndrome results from the inhibition of muscarinic cholinergic neurotransmission. Clinical manifestations can be remembered by the mnemonic, red as a beet, dry as a bone, blind as a bat, mad as a hatter, hot as a hare, and full as a flask. The mnemonic refers to the symptoms of flushing, dry skin and mucous membranes, mydriasis (dilated pupil) with loss of accommodation, altered mental status, fever, and urinary retention, respectively.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 181
Incorrect
-
A 42 year old female presents with a funny bone sensation in her right elbow that is accompanied by numbness and tingling in the 4th and 5th digits. The symptoms are aggravated when the elbow is bent for a prolonged period. Which of the following explains the most likely diagnosis?
Your Answer: Median nerve entrapment syndrome
Correct Answer: Cubital tunnel syndrome
Explanation:Cubital Tunnel Syndrome is a condition that involves pressure or stretching of the ulnar nerve (also known as the “funny bone” nerve), which can cause numbness or tingling in the 4th and 5th digit, pain in the forearm, and/or weakness in the hand. Epicondylitis of the elbow is a condition associated with repetitive forearm and elbow activities. Both lateral epicondylitis (commonly known as tennis elbow) and medial epicondylitis (commonly known as golfer’s elbow) are characterized by elbow pain during or following elbow flexion and extension. Radial tunnel syndrome is a set of symptoms that include fatigue or a dull, aching pain at the top of the forearm with use. Although less common, symptoms can also occur at the back of the hand or wrist.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 182
Incorrect
-
The Cellular Theory of Ageing involves?
Your Answer: Codon restriction
Correct Answer: Loss of telomeres
Explanation:Cellular theories of aging propose that human aging is the result of cellular aging, whereby an increasing proportion of cells reach senescence, a terminal stage at which cells will cease to divide. This will limit the body’s ability to regenerate and to respond to injury or stress. Telomeres are bits of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling, which could cause DNA to abnormally function. As cells replicate, telomeres shorten at the end of chromosomes, and this process correlates to senescence or cellular aging.
Other theories include:
- The Free Radical Theory: Implicates the gradual accumulation of oxidative cellular damage as a fundamental driver of cellular aging. This theory has evolved over time to emphasize the role of free radical induced mitochondrial DNA (mtDNA) mutations and the accumulation of mtDNA deletions. Given the proximity of mtDNA to the electron transport chain, a primary producer of free radicals, it postulates that the mutations would promote mitochondrial dysfunction and concomitantly increase free radical production in a positive feedback loop. It is known that diet, lifestyle, drugs (e.g. tobacco and alcohol) and radiation etc., are all accelerators of free radical production within the body.
- Error theory: based on the idea that errors can occur in the transcription of the synthesis of DNA. These errors are perpetuated and eventually lead to systems that do not function at the optimum level. The organism’s aging and death are attributable to these events (Sonneborn, 1979).
- The Cross-Linking Theory: also referred to as the Glycosylation Theory of Aging. In this theory it is the binding of glucose (simple sugars) to protein, (a process that occurs under the presence of oxygen) that causes various problems. Once this binding has occurred the protein becomes impaired and is unable to perform as efficiently. Living a longer life is going to lead to the increased possibility of oxygen meeting glucose and protein and known cross-linking disorders include senile cataract and the appearance of tough, leathery and yellow skin.
- The Neuroendocrine Theory First proposed by Professor Vladimir Dilman and Ward Dean MD, this theory elaborates on wear and tear by focusing on the neuroendocrine system. This system is a complicated network of biochemicals that govern the release of hormones which are altered by the walnut sized gland called the hypothalamus located in the brain. The hypothalamus controls various chain-reactions to instruct other organs and glands to release their hormones etc. The hypothalamus also responds to the body hormone levels as a guide to the overall hormonal activity. But as we grow older the hypothalamus loses it precision regulatory ability and the receptors which uptake individual hormones become less sensitive to them. Accordingly, as we age the secretion of many hormones declines and their effectiveness (compared unit to unit) is also reduced due to the receptors down-grading
- The Membrane Theory of Aging: According to this theory it is the age-related changes of the cell’s ability to transfer chemicals, heat and electrical processes that impair it. As we grow older the cell membrane becomes less lipid (less watery and more solid). This impedes its efficiency to conduct normal function and in particular there is a toxic accumulation
- The Decline Theory: The mitochondria are the power producing organelles found in every cell of every organ. Their primary job is to create Adenosine Triphosphate (ATP) and they do so in the various energy cycles that involve nutrients such as Acetyl-L-Carnitine, CoQ10 (Idebenone), NADH and some B vitamins etc. Enhancement and protection of the mitochondria is an essential part of preventing and slowing aging. Enhancement can be achieved with the above mention nutrients, as well as ATP supplements themselves.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 183
Incorrect
-
Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?
Your Answer: Alpha receptors
Correct Answer: Dihydropyridine receptors
Explanation:Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ form the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors.
Dihydropyridine receptors (DHPRs), are voltage-gated Ca2+ channels, and ryanodine receptors (RyRs), which are intracellular Ca2+ release channels, are expressed in diverse cell types, including skeletal and cardiac muscle.
Ryanodine receptors (RyRs) are located in the sarcoplasmic/endoplasmic reticulum membrane and are responsible for the release of Ca2+ from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 184
Incorrect
-
Choose the correct statement regarding trabecular bone:
Your Answer: Receives nutrients from bone ECF
Correct Answer: All of the options are correct
Explanation:Trabecular, spongy or cancellous bone. It is located inside the cortical bone and makes up around 20% of all bone in the body. It is made of spicules or plates with a high surface to volume ratio, where many cells sit on the surface of the end plates. It receives its nutrients from the extracellular fluid (ECF), exchanging about 10 mmol of calcium every 24 hours.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 185
Incorrect
-
Regarding Gene Knockout Mouse Models, all are true except:
Your Answer: RFLP can be sub categorised as slp( single locus proband mlp( multi locus probe).
Correct Answer: In knockout mouse models a gene is turned on through targeted mutation
Explanation:In knockout mouse models, a gene is not turned on but rather turned off or “knocked out” through targeted mutation. This involves disrupting or deleting the gene to study the effects of its loss of function. Knockout models are crucial for understanding the roles of specific genes, particularly those with unknown functions.
The other statements are true:
- Knockout models are important in studying the roles of sequenced genes with unknown function.
- RFLP (Restriction Fragment Length Polymorphisms) can be subcategorized as SLP (single locus probe) and MLP (multi locus probe).
- RFLP analysis is slow and cumbersome and is now largely obsolete, having been replaced by more efficient techniques.
- Sequence changes involved in RFLP can be analyzed more quickly by PCR (Polymerase Chain Reaction).
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This question is part of the following fields:
- Genetics
- Medicine
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Question 186
Incorrect
-
Which of the following drug can cause galactorrhoea?
Your Answer: Lisinopril
Correct Answer: Metoclopramide
Explanation:Metoclopramide causes extrapyramidal effects (especially in children and young adults), hyperprolactinaemia, and occasionally tardive dyskinesia on prolonged administration. Also reported are drowsiness, restlessness, diarrhoea, depression, neuroleptic malignant syndrome, rashes, pruritus, oedema.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 187
Incorrect
-
A 25-year-old female presents to the emergency department with severe breathlessness and tinnitus. She is under treatment for asthma and depression with albuterol and amitriptyline respectively.On examination, she seems agitated with a BP of 100/44, a pulse rate of 112 bpm, a respiratory rate of 30 cycles/min, and a temperature of 37.8'C.An arterial blood gas performed reveals:pH: 7.48 (7.36 – 7.44)pO2: 11.2 kPa (11.3 – 12.6 kPa)pCO2: 1.9 kPa (4.7 – 6.0 kPa)Bicarbonate: 13 mmol/l (20 – 28 mmol/L)What is the most probable diagnosis?
Your Answer: Panic attack
Correct Answer: Salicylate poisoning
Explanation:The blood gas analysis provided above is suggestive of a mixed respiratory alkalosis and metabolic acidosis characteristic of salicylate overdose.Pathophysiology:The direct stimulation of the cerebral medulla causes hyperventilation and respiratory alkalosis.As it is metabolized, it causes an uncoupling of oxidative phosphorylation in the mitochondria. Lactate levels then increase due to the increase in anaerobic metabolism. This, along with a slight contribution from the salicylate metabolites result in metabolic acidosis.Tinnitus is characteristic and salicylate ototoxicity may produce deafness. Other neurological sequelae include encephalopathy and agitation, seizures and CNS depression and coma. Cardiovascular complications include tachycardia, hypotension, and dysrhythmias (VT, VF, and asystole).
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 188
Incorrect
-
What is the function of the BK channel on the vascular smooth muscle membrane?
Your Answer: Promotes smooth muscle relaxation by opening the voltage gated Ca2+ channel
Correct Answer: Massive K+ efflux, increasing membrane potential, and shutting off the voltage gated Ca2+ channel
Explanation:BK channels, also known as large-conductance calcium-activated potassium channels, play a critical role in regulating vascular smooth muscle tone. When BK channels open, they allow a large efflux of potassium ions (K+) out of the cell. This efflux of K+ causes the membrane potential to become more negative (hyperpolarization), which in turn leads to the closure of voltage-gated calcium channels. The closure of these calcium channels reduces the influx of calcium ions (Ca2+) into the smooth muscle cells, resulting in decreased intracellular calcium levels and subsequent relaxation of the smooth muscle.
Thus, BK channels promote smooth muscle relaxation by hyperpolarizing the membrane and reducing the activity of voltage-gated Ca2+ channels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 189
Correct
-
A typical sleep cycle from stage 1 to the end of REM sleep in a normal adult is approximately how long?
Your Answer: 90 min
Explanation:A single sleep cycle has stages 1, 2, 3, 4 and REM (Rapid eye movement). These stages progress cyclically from 1 through to REM and then begin again with stage 1. A complete sleep cycle takes an average of 90-110 minutes, with each stage lasting between 5 to 15 minutes.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 190
Incorrect
-
The steps of cardiac cycle in sequence are:
Your Answer: Isovolumetric relaxation, isovolumetric contraction, ejection, passive ventricular filling, active ventricular filling
Correct Answer: Isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling.
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.1st stage: diastole, or passive filling is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. 2nd stage: atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle (active filling).3rd stage: isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. 4th stage: ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. 5th stage: isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 191
Incorrect
-
Somatostatin is responsible for?
Your Answer: Increased bile flow
Correct Answer: Decreased gastrin release
Explanation:Somatostatin is an inhibitory hormone secreted from the D cells of the Pancreatic Islets. It causes the inhibition of gastrin (decreasing stomach acid production), CCK (decreasing gallbladder motility), gastrin inhibitory peptide and secretin. Gastrin production is also inhibited by secretin, GIP, VIP, glucagon and calcitonin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 192
Correct
-
Colipase is secreted in an inactive form. Its activation in the intestinal lumen is by
Your Answer: Trypsin
Explanation:The enzyme trypsin exists in pancreatic juice in the inactive form trypsinogen, it is activated by the intestinal enterokinase in intestinal juice. Trypsin can then activate other protease enzymes and catalyse the reaction pro-colipase → colipase. Colipase is necessary, along with bile salts, to enable lipase function.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 193
Correct
-
Which of the given adverse effects should be anticipated following the administration of an anticholinesterase?
Your Answer: Bradycardia and miosis
Explanation:Bradycardia and miosis should be anticipated following the administration of anticholinesterases.Anticholinesterase agents include the following medications:- Pyridostigmine, neostigmine, and edrophonium which play a significant role in the diagnosis and the management of myasthenia gravis.- Rivastigmine, galantamine and donepezil are cholinesterase inhibitors found to be significantly useful in the management of Alzheimer’s disease.Mechanism of action and pharmacological effects:Inhibition of cholinesterase increases the level and the duration of action of acetylcholine within the synaptic cleft. Thus, cholinergic effects such as a reduction in heart rate (bradycardia), miosis (pupillary constriction), increased secretions, increased gastrointestinal motility and reduction in BP may occur with anticholinesterases.Toxins such as organophosphates and carbamates also are primarily anticholinergic and cause the following typical SLUDGE symptoms:- Salivation- Lacrimation- Urination- Diaphoresis- Gastrointestinal upset- Emesis
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 194
Correct
-
Where is the lower border of the liver usually found?
Your Answer: 10th rib anterior axillary line on right
Explanation:Assessment of liver margins is important clinically to determine the size of the liver and is done via percussion during the physical examination. The liver typically extends from the fifth intercostal space or 6th rib to the right costal margin in the midclavicular line and the 10th rib on anterior axillary line.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 195
Incorrect
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With regards to P53, which statement is NOT true?
Your Answer: P53’s own expression is induced by broken DNA
Correct Answer: P53 is a RNA binding protein
Explanation:P53 is a tumour suppressor gene. It is not an RNA binding protein. It has been implicated in almost all tumours. It regulates the progression from G1 to the S phase of the cell cycle and is activated in response to damaged DNA.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 196
Incorrect
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A 34 year old woman presents to the emergency department due to right sided weakness. Past history reveals a DVT following the birth of her daughter, and two miscarriages. Head CT confirms an ischaemic stroke in the territory of left middle cerebral artery. What would be the most likely finding on echocardiography?
Your Answer: Bicuspid aortic valve
Correct Answer: Normal
Explanation:The patient most likely suffers from antiphospholipid syndrome. The clinical criteria consist of vascular thrombosis and pregnancy morbidity. Vascular thrombosis is defined as one or more clinical episodes of arterial, venous, or small-vessel thrombosis in any tissue or organ confirmed by findings from imaging studies, Doppler studies, or histopathology. ASD, VSDs would cause paradoxical emboli and stroke, however the recurrent pregnancy loss in this case is strongly suggestive of antiphospholipid syndrome. The ECG would be normal in most cases associated with anti phospholipid syndrome.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 197
Incorrect
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Periodic fevers occur in humans with mutations in the gene for pyrin. Pyrin is a protein found in which one of the following cells?
Your Answer:
Correct Answer: Neutrophils
Explanation:Pyrin, also known as marenostrin or TRIM20, is a protein encoded by the Mediterranean fever (MEFV) gene, causing the autoinflammatory disease familial Mediterranean fever (FMF). Pyrin produces an increased sensitivity to intracellular signals. It is produced mainly in neutrophils, which display an increased ratio of cells entering apoptosis when exposed to pyrin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 198
Incorrect
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Initial depolarization of cardiac muscle is due to influx of:
Your Answer:
Correct Answer: Na+
Explanation:Initial depolarization of the cardiac muscle results from opening of the sodium voltage gated channels. This results in the influx of sodium and an increase in the membrane potential towards threshold. Potassium efflux results in repolarization.
The cardiac action potential has 5 phases:
- Phase 0—depolarization because of the opening of fast sodium channels. Potassium flux also decreases.
- Phase 1—partial repolarization because of a rapid decrease in sodium ion passage as fast sodium channels close.
- Phase 2—plateau phase in which the movement of calcium ions out of the cell, maintains depolarization.
- Phase 3—repolarization, sodium, and calcium channels all close and membrane potential returns to baseline.
- Phase 4—resting membrane potential (−90 mV), resulting from the activity of the Na+/K+ ATPase pump which creates a negative intracellular potential because of the exchange of three sodium ions for only two potassium ions.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 199
Incorrect
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A 50-year-old male presents to the ER allegedly claiming that he consumed a bottle of antifreeze. Which of the following symptoms is least likely to be associated with this kind of poisoning?
Your Answer:
Correct Answer: Hypertension
Explanation:Loss of vision after consumption of antifreeze is a characteristic presentation of methanol poisoning.
Pathophysiology of methanol toxicity: When ingested, methanol is absorbed rapidly via the gastrointestinal tract in less than 10 minutes. Methanol is not protein-bound and is absorbed directly into the total body water compartment. Metabolism occurs mainly in the liver through serial oxidation via alcohol dehydrogenase and aldehyde dehydrogenase but begins with alcohol dehydrogenase present in the gastric mucosa. Alcohol dehydrogenase oxidizes methanol to formaldehyde, and aldehyde dehydrogenase subsequently oxidizes formaldehyde to formic acid. Formic acid is the primary toxic metabolite that accounts for the associated anion gap metabolic acidosis and end-organ damage.
Clinical presentation: Patients who present within the first 12 to 24 hours following ingestion may appear normal, and this is described as the latent period. Nausea, vomiting, and abdominal pain subsequently ensue, followed by CNS depression and hyperventilation due to metabolic acidosis. Ocular symptoms associated with retinal toxicity are often evident in the form of blurry vision, decreased visual acuity, photophobia, and “halo vision.”
Treatment: Treatment options for methanol toxicity include supportive care, fomepizole (Antizole, 4-Methylpyrazole or 4MP), ethanol, dialysis, and folate.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 200
Incorrect
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Which of the following factors is most likely to lead to an increase in serum cortisol levels?
Your Answer:
Correct Answer: Severe emotional stress
Explanation:Cortisol is widely known as the stress hormone. Alterations in cortisol levels have been found in relation to mood disorders, illness, trauma, pain, fear, exertion, and anxiety, amongst other stimuli.
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This question is part of the following fields:
- Endocrinology
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
