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Question 1
Correct
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Regarding the structure of the 3 pituitary glycoprotein hormones FSH, LH, and TSH, which of the following is true about the α- and β-subunits of each hormone?
Your Answer: Maximal physiological activity occurs only on their combination
Explanation:Glycoprotein hormones (GPHs) are the most complex molecules that function as hormones. They each consist of two different subunits, α and β, which are non-covalently associated. The combination of these subunits results in an increase in their activity and β structure.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 2
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 3
Correct
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A 50-year-old farmer, under treatment for depression, presents to the emergency department following an intentional overdose of an unidentified substance. On examination, he was found to be bradycardic, hypotensive, hyper-salivating, and disoriented. On ocular examination, his pupils were found to be miotic. What is the most likely substance he ingested?
Your Answer: An organophosphate insecticide
Explanation:The farmer has most likely ingested an organophosphate insecticide.Organophosphorus compounds are used widely as:• Insecticides – Malathion, parathion, diazinon, dichlorvos• Nerve gases – Soman, sarin, tabun, VX• Ophthalmic agents – Echothiophate• Antihelmintics – Trichlorfon• Herbicides – merphos• Industrial chemical (plasticizer) – Tricresyl phosphateSigns and symptoms of Organophosphorus Poisoning (OPP) can be classified as:• Muscarinic effects:o Cardiovascular – Bradycardia, hypotensiono Respiratory – Rhinorrhoea, bronchorrhea, bronchospasm, cough, severe respiratory distresso Gastrointestinal – Hypersalivation, nausea and vomiting, abdominal pain, diarrhoea, faecal incontinenceo Genitourinary – Incontinenceo Ocular – Blurred vision, miosiso Glands – Increased lacrimation, diaphoresis• Nicotinic effects:o Muscle fasciculation, weakness, cramping, diaphragmatic failure, and autonomic side effects include: hypertension, tachycardia, and mydriasis.• Central nervous system (CNS) effects:o Anxiety, emotional lability, restlessness, confusion, ataxia, tremors, seizures, coma, apnoeaMainstay Treatment:• Decontamination• Securing Airway, Breathing and Circulation• Atropine• Pralidoxime• Benzodiazepines
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 4
Correct
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An 18 year old boy, thin with a tall stature, and a high arched palate arrives at the hospital with a spontaneous pneumothorax. He is accompanied by his brother who has a similar appearance. You suspect Marfan's Syndrome. The gene encoding which of the following proteins is defective in this condition?
Your Answer: Fibrillin-1
Explanation:A variety of proteins compose the structure of microfibrils, the most prominent of which are the two fibrillins. Fibrillin-1 a scaffolding protein is encoded by FBN1 on human chromosome 15q21 and fibrillin-2 is encoded by FBN2 on 5q23. Mutations in FBN1 produce Marfan syndrome, a pleiotropic autosomal dominant connective tissue disorder with prominent manifestations in the skeleton, eye and cardiovascular system. A number of conditions related to Marfan syndrome are also due to FBN1 mutations.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 5
Correct
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In a patient with prostate cancer, what is the mechanism by which goserelin acts?
Your Answer: GnRH agonist
Explanation:Androgen deprivation therapy (ADT) for prostate cancer:Goserelin (Zoladex) is a synthetic gonadotropin-releasing hormone (GnRH) analogue; chronic stimulation of goserelin results in suppression of LH, FSH serum levels thereby preventing a rise in testosterone.Dosage form: 3.6 mg/10.8mg implants.Adverse effects include flushing, sweating, diarrhoea, erectile dysfunction, less commonly, rash, depression, hypersensitivity, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 6
Correct
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Medullary chemoreceptors
Your Answer: Monitor H+ concentration of the CSF
Explanation:Central chemoreceptors of the central nervous system, located on the ventrolateral medullary surface in the vicinity of the exit of the 9th and 10th cranial nerves, are sensitive to the pH of their environment. These act to detect the changes in pH of nearby cerebral spinal fluid (CSF) that are indicative of altered oxygen or carbon dioxide concentrations available to brain tissues.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 7
Incorrect
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Which of the following statements is most suitable to describe necrosis?
Your Answer: Shrinking of cytoplasm and condensation of nucleus.
Correct Answer: Significant inflammatory response
Explanation:Necrosis is the death of most or all of the cells in an organ or tissue due to disease, injury, or failure of the blood supply. Cellular death due to necrosis does not follow the (regulated) apoptotic signal transduction pathway, but rather various receptors are activated, and result in the loss of cell membrane integrity and an uncontrolled release of products of cell death into the extracellular space. This initiates in the surrounding tissue an inflammatory response which attracts leukocytes and nearby phagocytes which eliminate the dead cells by phagocytosis.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 8
Incorrect
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A 28 year old man was rushed to the hospital after experiencing sudden onset chest pain while playing football. He has never felt such pain in the past. However, one of his uncles had a similar sudden discomfort at a young age and he passed away following a heart problem. The following vitals are recorded on examination:BP: 101/74 mmHgRR: 22 breaths/minPR: 87 beats/min Physical examination reveals abnormally long fingers and on asking the man to hold the opposite wrist, the thumb and little finger overlap each other. He is not taking any medication regularly and past medical/surgical history is not significant. He admits to smoking half pack of cigarettes/day for the last 10 years but denies abusing any illicit drugs. Which of the following explanation most likely explains the disease process in this man?
Your Answer: Impaired hydroxylation of lysine and proline amino acids on collagen
Correct Answer: A defect of the glycoprotein structure which usually wraps around elastin
Explanation:Aortic dissection is defined as separation of the layers within the aortic wall. Tears in the intimal layer result in the propagation of dissection (proximally or distally) secondary to blood entering the intima-media space. This can be caused as a result of both congenital or acquired factors like chronic uncontrolled hypertension. This patient shows no sign of hypertension but his physical examination hints towards Marfan Syndrome. Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder affecting the microfibrils and elastin in connective tissue throughout the body. MFS is associated with pathological manifestations in the cardiovascular system (e.g., mitral valve prolapse, aortic aneurysm, and dissection), the musculoskeletal system (e.g., tall stature with disproportionately long extremities, joint hypermobility), and the eyes (e.g., subluxation of the lens of the eye). Decreased collagen production occurs in ageing, hydroxylation defects are present in vitamin C deficiency, copper deficiency affecting lysyl oxidase enzyme occurs in Menke’s disease.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 9
Correct
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A 22 year old man is being evaluated for chronic lower backache. Which of the following would most strongly point towards the diagnosis of ankylosing spondylitis?
Your Answer: Reduced lateral flexion of the lumbar spine
Explanation:Ankylosing spondylitis (spondylarthritis) is a chronic inflammatory disease of the axial skeleton that leads to partial or even complete fusion and rigidity of the spine. Males are disproportionately affected and upwards of 90% of patients are positive for the HLA-B27 genotype, which predisposes to the disease. The most characteristic early finding is pain and stiffness in the neck and lower back, caused by inflammation of the vertebral column and the sacroiliac joints. The pain typically improves with activity and is especially prominent at night. Other articular findings include tenderness to percussion and displacement of the sacroiliac joints (Mennell’s sign), as well as limited spine mobility, which can progress to restrictive pulmonary disease. The most common extra-articular manifestation is acute, unilateral anterior uveitis. Diagnosis is primarily based on symptoms and x-ray of the sacroiliac joints, with HLA-B27 testing and MRI reserved for inconclusive cases. There is no curative treatment, but regular physiotherapy can slow progression of the disease. Additionally, NSAIDs and/or tumour necrosis factor-α inhibitors may improve symptoms. In severe cases, surgery may be considered to improve quality of life. The spine adopts a bamboo shape, not lordosis. The pain usually improves as the day progresses. leg raise test causes pain in cases of meningitis etc not in this case.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 10
Correct
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Question 11
Incorrect
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The function of ATP in cardiac muscle contraction includes:
Your Answer: Uncovering the actin binding site
Correct Answer: Binding to myosin after the power stroke to allow uncoupling of actin and myosin
Explanation:After calcium binds to the troponin C, there is a conformational change in the structure of troponin I and tropomyosin, which moves out of the way and frees the site where myosin can bind to actin. This results in the formation of the cross linkage of the actin and myosin giving rise to the power stroke in the contraction phase. This occurs with the release of ADP. When ATP combines to this complex it breaks and the cycle repeats itself.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 12
Incorrect
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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 13
Incorrect
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What is the function of the acute phase protein, C-reactive protein?
Your Answer: Activates complement
Correct Answer: Opsonises bacteria
Explanation:There are various immune reactions that become activated once the barrier between the body and environment has been compromised. There are certain opsonins that bind to the bacteria and facilitate phagocytosis. One of them is the acute phase protein: C protein. others include antibodies and complement.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 14
Incorrect
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Which of the following groups are purines?
Your Answer: Adenine, guanine, thymidine
Correct Answer: Adenine, guanine, hypoxanthine
Explanation:There are many naturally occurring purines. They include the nucleobases, adenine and guanine. Other notable purines are hypoxanthine, xanthine), theobromine, caffeine, uric acid and isoguanine.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 15
Incorrect
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An obstruction in a pulmonary artery causes impaired perfusion to an area in the lung. The gas values in the unperfused alveoli at sea level will be:
Your Answer: PO2 = 104 CO2 = 40
Correct Answer: PO2 = 149 C02 =0
Explanation:Partial pressure of oxygen at sea level is approximately 160 mmHg. Partial pressure of oxygen in alveoli is around 150 mmHg and in an arteriole is around 80-100 mmHg. Partial pressure of carbon dioxide is around 35 mmHg in alveolar air and around 40 mmHg in the arteriole.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 16
Incorrect
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Absorption of protein antigens i.e. bacterial and viral proteins takes place in the:
Your Answer: Mucosa-associated lymphoid tissue
Correct 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 LieberkĂ¼hn 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 17
Correct
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During which stage does the mitotic apparatus dissolute?
Your Answer: Telophase
Explanation:In telophase the nuclear envelope along with the nucleolus will reappear. The daughter nuclei will enlarge as the chromosome will decondense again. Along with this, cytokinesis will occur. At the end of cytokinesis the daughter centrioles will move from the poles to the intercellular bridge where they will be disassembled and complete the separation of the daughter cells
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This question is part of the following fields:
- Genetics
- Medicine
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Question 18
Correct
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Preload:
Your Answer: Is the degree to which the myocardium is stretched before is contracts
Explanation:Preload is end diastolic volume. It is the degree to which the heart muscle fiber is stretched when it fills up completely just before the heart contracts.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 19
Incorrect
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Which intestinal cells play a major role in secretory immunity?
Your Answer: B cells
Correct Answer: M cells
Explanation:M cells are specialized epithelial cells of the MALT or mucosa-associated lymphoid tissues. They transport antigens from the intestinal lumen to cells of the immune system, thereby initiating an immune response. T and B cells are lymphocytes found in blood. Mucous cells secrete mucous and can be considered as a part of innate immunity. Chief cells in the gastric mucosa secret pepsin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 20
Correct
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During which phase of the cardiac cycle does most of the ventricular filling occur?
Your Answer: Ventricular diastole
Explanation:During the phase of ventricular diastole when the heart muscle relaxes and all the valves are open, blood flows easily into the heart. This is the phase of rapid ventricular filling. During isovolumetric contraction and relaxation the volume of blood in the heart does not change. During ventricular ejection blood enters into the aorta and pulmonary vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 21
Correct
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A sarcomere is the area between:
Your Answer: Two adjacent z lines
Explanation:The area that lies between the two adjacent Z lines is known as a sarcomere and is the contractile unit of the muscle. The line passing in the middle of the myosin filaments is the M line. It also passes through the middle of the sarcomere.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 22
Correct
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Carbohydrates digestion starts in the
Your Answer: Mouth
Explanation:Digestion begins in the mouth with the secretion of saliva and its digestive enzymes. Food is formed into a bolus by the mechanical mastication and swallowed into the oesophagus from where it enters the stomach through the action of peristalsis.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 23
Incorrect
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Which of the following is false with regard to the following statement: Proto- oncogenes can be transformed to oncogenes in the following ways.
Your Answer: Mutations in the genomic DNA
Correct Answer: Inhibition of P53
Explanation:Proto oncogenes cannot be transformed into oncogenes due to inhibition of P53 gene. There has to be a mutation in the proto oncogene. All the other options are true.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 24
Correct
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A 26 year old male presents with right sided elbow and wrist pain and left sided knee and ankle pain that has persisted for about two weeks. He recently returned from a trip to Thailand that last for two weeks. The patient admits to having unprotected sex while on holiday. Examination reveals swelling and tenderness of tendons around joints but no inflammation of the joints. A vesiculopustular skin rash is also observed. What is the most likely cause?
Your Answer: Gonococcal arthritis
Explanation:Patients with disseminated gonococcal arthritis may present with dermatitis-arthritis syndrome (60%) of with localized septic arthritis. (40%). Arthritis-dermatitis syndrome includes the classic triad of dermatitis, tenosynovitis, and migratory polyarthritis. Gout usually involves a singe joint and does not cause vesicopustular skin rash. Reactive arthritis has ocular symptoms (conjunctivitis), urethritis, and arthritis. Fungal arthritis occurs rarely and it may occur after a surgical infection or fungal spread hematogenously. it presents with tender, red, hot and swollen joint with loss of range of motion.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 25
Incorrect
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Regarding carbohydrates absorption;
Your Answer: Glucagon greatly decrease intestinal transport of sugars
Correct Answer: Intestinal absorption of sugars is inhibited by the drug phlorizin
Explanation:The main role of insulin is in the uptake of glucose from blood to tissues where it is metabolised. Glycose transporters in the intestines do not depend on the action of insulin. Phlorizin is a competitive inhibitor of SGLT1 and SGLT2 because it competes with glucose for the binding site, reducing intestinal and renal glucose transport.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 26
Incorrect
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Question 27
Correct
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Which of the following treatments would you advise for a young, 21 year old student who has ankylosing spondylitis and complains of worsening back pain and morning stiffness?
Your Answer: Oral NSAIDs
Explanation:NSAIDs are considered as the first line of treatment for managing pain and stiffness associated with ankylosing spondylitis. Other useful medications include TNF-alpha inhibitors. Other drugs like paracetamol, colchicine, and steroids are not routinely used. Bilateral total hip replacement might be indicated in advanced disease contrary to complicated spinal surgery.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 28
Incorrect
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The cells that secrete pepsinogen and gastric lipase are found in which part of the stomach?
Your Answer: Fundus
Correct Answer: Body and fundus
Explanation:Stomach can be divided in to different regions. Cardia, fundus, body, antrum and pylorus from proximal end to distal end respectively. Cells that secret the inactive form of pepsin or pepsinogen are chief cells and are abundant in the body (corpus) and the fundus region of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 29
Incorrect
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The coronary arteries supply which part of the heart’s subendocardial region exclusively in diastole?
Your Answer: All chambers of the heart ( all of the above if you want )
Correct Answer: Left ventricle
Explanation:It is only during diastole that the blood flows to the subendocardial portion of the left ventricle, as the heart muscle relaxes and the coronary arteries regain their patency.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 30
Correct
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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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SESSION STATS - PERFORMANCE PER SPECIALTY
