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Question 1
Correct
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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: 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 2
Correct
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Why is the sub-endocardial portion of the left ventricle the most common site for ischaemic damage and myocardial infarction?
Your Answer: No blood flow occurs during systole
Explanation:The subendocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure due to contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the subendocardium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Incorrect
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The ability of the SA node cells to allow ionic flow through channels activated in a hyperpolarized state is known as:
Your Answer: Depolarization
Correct Answer: Pace maker potential
Explanation:Rhythmically discharging cells have a membrane potential that, after each impulse, declines to the firing level. Thus this prepotential or Pacemaker potential triggers the next impulse. The inherent leakiness of the sinus nodal fibers to Na+ and Ca2+ causes their self excitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 4
Correct
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What is found in the posterior cavity of the eye?
Your Answer: Vitreous humor
Explanation:The eye ball contains an anterior cavity and a posterior cavity. The anterior cavity once again is divided into the anterior chamber and posterior chamber. The anterior cavity is filled with aqueous humor whereas the posterior cavity contains vitreous humor.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 5
Correct
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The coronary sinus, which empties into the right atrium, serves to?
Your Answer: Drain the venous supply of the myocardium
Explanation:The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena cava.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Correct
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A 42 year old obese man complains of a painful swollen ankle. The pain has worsened over the past 2 weeks. He is a diabetic and gives a history of recent alcohol consumption. Joint aspirate shows rhomboid crystals with numerous neutrophils. Radiological examination shows evidence of chondrocalcinosis. Which of the following is the most likely diagnosis?
Your Answer: Pseudogout
Explanation:Pseudogout is a paroxysmal joint inflammation due to calcium pyrophosphate crystal deposition (calcium pyrophosphate dihydrate). Aetiology includes mostly idiopathic (primary form) and secondary form occurring as a result of joint trauma, familial chondrocalcinosis, hyperparathyroidism, hemochromatosis, gout, hypophosphatemia. Clinical presentation: Often asymptomatic. Acute (pseudogout attack): monoarthritis (rarely oligoarthritis), mostly affecting the knees and other large joints (e.g., hips, wrists, and ankles). It may become chronic (can affect multiple joints). Osteoarthritis with CPPD (most common form of symptomatic CPPD): progressive joint degeneration with episodes of acute inflammatory arthritis typical of pseudogout attacks. Arthrocentesis should be performed, especially in acute cases. Polarized light microscopy: detection of rhomboid-shaped, positively birefringent CPPD crystals. Synovial fluid findings: 10,000-50,000 WBCs/μL with > 90% neutrophils. X-ray findings: cartilage calcification of the affected joint (chondrocalcinosis). Fibrocartilage (meniscus, annulus fibrosus of intervertebral disc) and hyaline cartilage (joint cartilage) may be affected.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 7
Correct
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A 38-year-old woman has a melanocytic naevi on her left forearm.Which of the following features do not suggest malignant change?
Your Answer: Decrease in size
Explanation:Melanocytic nevi are benign neoplasms or hamartomas composed of melanocytes. Melanocytes are derived from the neural crest and migrate during embryogenesis to selected ectodermal sites (primarily the skin and the CNS), but also to the eyes and the ears.They tend to appear during early childhood and during the first 30 years of life. They may change slowly, becoming raised, changing color or gradually fading.. Pregnancy can increase the number of naevi as well as the degree of hyperpigmentation.They may become malignant and this should be suspected if the naevus increases in size, develops an irregular surface or becomes darker, itches or bleeds.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 8
Correct
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The following is true of the sinus node:
Your Answer: It generates impulses automatically & at a quicker rate than other cardiac cells
Explanation:The SA node exhibits automaticity. It generates the impulses to which the heart beats. It fires at a faster speed than the rest of the nervous components of the heart i.e. the AV nodes, purkinje fibers. This is the reason when the SA node fails the heart beats to the rhythm of the AV node.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 9
Correct
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A 62-year-old software developer with lung cancer is currently taking MST 30mg bd for pain relief. What dose of oral morphine solution should he be prescribed for breakthrough pain?
Your Answer: 10 mg
Explanation:The total daily morphine dose is 30 x 2 = 60 mg. Therefore, the breakthrough dose should be one-sixth of this, 10 mg.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 10
Correct
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The enzyme located on the brush border of the small intestine activating the proteolytic enzymes for further digestion of proteins is called?
Your Answer: Enterokinase
Explanation:Enterokinase is a brush border enzyme of the duodenum that activates proteolytic enzymes for further digestion of proteins. Trypsinogen is converted to trypsin by the action of enterokinase. Trypsin and chymotrypsin are secreted by the pancreatic acinar cells and are enzymes that aid in protein digestion. Pepsin is secreted by chief cells of the gastric mucosa. Procarboxydase is the inactive form of carboxypeptidase which is converted to its active form by trypsin and is secreted by pancreatic acinar cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 11
Correct
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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: 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 12
Correct
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What is the most appropriate management of a DVT during pregnancy?
Your Answer: Heparin
Explanation:Low molecular weight heparin (LMWH) is safe in pregnancy and is therefore the first line management. Warfarin is teratogenic and must be avoided whilst the other options have no role to play.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 13
Correct
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Tumour necrosis factor is a cytokine. What is its major function?
Your Answer: Promotion of inflammation
Explanation:Tumour necrosis factor (TNF) is a cytokine that has a wide variety of functions. It can cause cytolysis of certain tumour cell lines; it is involved in the induction of cachexia; it is a potent pyrogen, causing fever by direct action or by stimulation of interleukin-1 secretion; it can stimulate cell proliferation and induce cell differentiation under certain conditions.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 14
Correct
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Approximately what percentage of the world is infected with tuberculosis:
Your 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 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
Correct
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A 42-year-old female with type 1 diabetes who has undergone a renal transplant is being reviewed. She is taking azathioprine and tacrolimus for immunosuppression.Which among the following is correct regarding the given immunosuppressive agents?
Your Answer: Tacrolimus is a calcineurin inhibitor
Explanation:Tacrolimus is a calcineurin inhibitor used as an immunosuppressive agent used for prophylaxis of organ rejection post-transplant.Pharmacology: Calcineurin inhibition leads to reduced T-lymphocyte signal transduction and IL-2 expression. It has a half-life of 12 hours (average).Other off-label indications for the use of tacrolimus include Crohn disease, graft-versus-host disease (GVHD), myasthenia gravis, rheumatoid arthritis.Adverse effects of tacrolimus includes: Cardiovascular: Angina pectoris, cardiac arrhythmias, hypertensionCentral nervous system: Abnormal dreams, headaches, insomnia, tremors.Dermatologic: Acne vulgaris, alopecia, pruritis, rashEndocrine and metabolic: Decreased serum bicarbonate, decreased serum iron, new-onset diabetes mellitus after transplant (NODAT), electrolyte disturbances.Gastrointestinal: Abdominal pain, nausea, vomiting, diarrhoeaGenitourinary: Urinary tract infectionHepatic: Abnormal hepatic function testsNeuromuscular and skeletal: Arthralgia, muscle crampsOphthalmic: Blurred vision, visual disturbanceOtic: Otalgia, otitis media, tinnitusRenal: Acute renal failureOther options:Sirolimus (a macrolide) is an mTOR inhibitor that blocks the response to IL-2 and has a half-life of 12–15 hours. Azathioprine inhibits purine synthesis, an essential step in the proliferation of white cells and has a half-life of around 5 hours.
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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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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:All are true for autosomal recessive disorders. Dominance rules for sex-linked gene loci are determined by their behaviour in the female: because the male has only one allele (except in the case of certain types of Y chromosome aneuploidy), that allele is always expressed regardless of whether it is dominant or recessive.
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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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Which of the following conditions has no effect on cardiac output?
Your Answer: Sleep
Explanation:Sleep has no effect on the cardiac output. Anxiety, excitement and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.
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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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The basic taste “umami” is mediated by glutamate acting on a metabotropic receptor named:
Your Answer: ENAC
Correct Answer: mGluR4
Explanation:Umami taste or savoury taste is one of the five basic tastes described as meaty or brothy. Umami taste receptors typically respond to Glutamate. Biochemical studies have identified the taste receptors responsible for the sense of umami as modified forms of mGluR4, mGluR1 and taste receptor type 1 (T1R1), all of which have been found in all regions of the tongue bearing taste buds.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 20
Incorrect
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Which of the following does not contribute to increased stroke volume during exercise?
Your Answer: Increased sympathetic stimulation of ventricular muscle
Correct Answer: Increased length of filling time during diastole
Explanation:Prolonged aerobic exercise training may also increase stroke volume, which frequently results in a lower (resting) heart rate. Reduced heart rate prolongs ventricular diastole (filling), increasing end-diastolic volume, and ultimately allowing more blood to be ejected.
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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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Which dorsal (sensory) root is responsible for umbilical area sensation?
Your Answer: T10
Explanation:The area of skin supplied by one nerve is called a dermatome. T10 supplies sensory neurons to the area of the umbilicus. C3 and C4 supply the neck and the shoulder, T4 supplies the dermatome at the level of the nipple, S3 supplies the inguinal region and L5 supplies the lateral aspect of the leg and the medical aspect of the dorsum of the feet plus the first 3 toes.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 22
Incorrect
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The hepatic plates in the liver parenchyma consist of how many cell layers?
Your Answer: 10 – 50 cell layers
Correct Answer: 1 – 2 cell layers
Explanation:Hepatic plates in a hepatic lobule are arranged in 1-2 cell layers.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 23
Correct
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The pyloric sphincter is largely made up of thickening of
Your 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 24
Correct
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An exaggerated response to a noxious stimulus is called:
Your Answer: Hyperalgesia
Explanation:Allodynia is the sensation of pain following non-painful stimulation.
Hyperalgesia is enhanced intensity of pain sensation.
Causalgia is a constant burning pain resulting from peripheral nerve injury.
Hyperesthesia is the abnormal increase in sensitivity to stimuli of sense.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 25
Correct
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Question 26
Correct
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Which of the following statements is the most characteristic of primary Raynaud's phenomena?
Your Answer: Fingers are symmetrically involved during an attack
Explanation:A typical attack may last less than an hour but can also persist for longer. In primary Raynaud’s, attacks are more likely symmetric, episodic, and without evidence of peripheral vascular disease. Patients more commonly have a negative ANA and normal inflammatory markers. There should be no evidence of tissue gangrene, digital pitting, or tissue injury in primary Raynaud’s. In contrast, patients with secondary Raynaud’s will describe attacks that are more frequent, painful, often asymmetric and may lead to digital ulcerations.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 27
Correct
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Embryologically the anterior pituitary is formed from?
Your Answer: Rathkes pouch
Explanation:The ectoderm, located in the roof of the pharynx, forms Rathke’s pouch, which comes into contact with the ectoderm of the developing brain. The pouch eventually separates from the pharynx, becoming the anterior pituitary.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 28
Incorrect
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HCL is secreted by which cells in the stomach
Your Answer: G cells
Correct Answer: Parietal cells
Explanation:Parietal cells are the epithelial cells that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and in the body 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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In which phase do chromosomes in the nucleus become condensed into well-defined chromosomes?
Your Answer: Anaphase
Correct 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 30
Incorrect
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Catecholamines…
Your Answer: Decrease camp production
Correct Answer: Activate adenylyl cyclase
Explanation:Norepinephrine and epinephrine activate or deactivate adenylyl cyclase resulting in a decrease or an increase in the production of cAMP.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 31
Incorrect
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“Ploidy” is a term used to refer to the number of chromosomes in cells. Cancer cells are commonly:
Your Answer: Euploidy
Correct Answer: Aneuploidy
Explanation:Cancer cells most commonly undergo disordered cell growth and cell division. This results in an additional number of chromosomes called aneuploidy. This is a characteristic of cancer cells along with variation in differentiation of the cells.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 32
Correct
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Which glucose transporter is responsible for the uptake of dietary glucose from the gut?
Your Answer: SGLT1
Explanation:SGLT 1 is responsible for the uptake of glucose via secondary active transport from the small intestine and the renal tubules.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 33
Incorrect
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Which segment of the nephron is impermeable to water?
Your Answer: Distal convoluted tubule
Correct Answer: Ascending limb of Henle
Explanation:Considerable differences aid in distinguishing the descending and ascending limbs of the loop of Henle. The descending limb is permeable to water and noticeably less permeable to salt, and thus only indirectly contributes to the concentration of the interstitium. Unlike the descending limb, the thin ascending limb is impermeable to water, a critical feature of the counter current exchange mechanism employed by the loop.
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This question is part of the following fields:
- Medicine
- Renal
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Question 34
Correct
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Question 35
Correct
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The major factor in controlling coronary artery blood flow is considered to be?
Your Answer: Metabolites of oxygen consumption
Explanation:There is a strong relationship between myocardial blood flow and oxygen consumption. This indicates that products of metabolism may cause vasodilation of the coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 36
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 37
Incorrect
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Which of the following are true when it comes to tumour suppressor genes:
Your Answer: Mutation in the Rb gene leads to retinoblastoma
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 38
Correct
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Question 39
Correct
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The residual cleft of the intermediate lobe of the pituitary is lined by follicles resembling which human gland?
Your 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 40
Incorrect
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Number of cases that are infected at a specific point in time
Your Answer: Sero-Prevalence
Correct Answer: Prevalence
Explanation:Prevalence in epidemiology is the proportion of a population found to have a condition (typically a disease or a risk factor such as smoking or seat-belt use). It is arrived at by comparing the number of people found to have the condition with the total number of people studied, and is usually expressed as a fraction, as a percentage or as the number of cases per 10,000 or 100,000 people. Point prevalence is the proportion of a population that has the condition at a specific point in time. Period prevalence is the proportion of a population that has the condition at some time during a given period (e.g., 12 month prevalence), and includes people who already have the condition at the start of the study period as well as those who acquire it during that period. Lifetime prevalence (LTP) is the proportion of a population that at some point in their life (up to the time of assessment) have experienced the condition
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 41
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 42
Incorrect
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Which of the following intercellular connections is important in endothelial barrier function?
Your Answer: Desmosomes
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 43
Correct
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Question 44
Correct
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The haustral pattern seen in the normal colon is produced by
Your Answer: Taenia coli
Explanation:The haustra (singular haustrum) of the colon are the small pouches caused by sacculation (sac formation), which give the colon its segmented appearance. The teniae coli run the length of the large intestine. Because the taeniae coli are shorter than the intestine, the colon becomes sacculated between the taeniae coli, forming the haustra.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 45
Correct
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Question 46
Correct
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With regards to P53, which statement is NOT true?
Your 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 47
Correct
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The process of DNA amplification and quantification is called:
Your Answer: PCR
Explanation:PCR/polymerase chain reaction is a procedure carried out in a test tube that can be used on the smallest amount of DNA to amplify it, allowing for millions of copies of specific nucleotides to be made.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 48
Correct
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One function of the liver is synthesis and storage of protein. Which of the following will result in hypoalbuminemia?
Your Answer: All of the above
Explanation:Both trauma and sepsis cause an acute inflammatory response causing plasma leakage of albumin. Nephropathy causes leakage of albumin from glomeruli and excretion of albumin in urine known as albuminuria. A hypercatabolic state is characterized by increased circulating catabolic hormones and increase break down of proteins.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 49
Incorrect
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Which of the following factors is directly responsible for the breakdown of fibrinogen to fibrin?
Your Answer: Plasmin
Correct Answer: Thrombin
Explanation:Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the coagulation cascade, the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalysing many other coagulation-related reactions.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 50
Correct
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The transporter responsible for most glucose absorption in the lumen of the small intestine is called?
Your Answer: SGLT 1
Explanation:GLUT = Glucose transporter. GLUT are a family of proteins of different types. GLUT 1 is mainly expressed in erythrocytes, whereas GLUT 2 is mainly expressed by, liver cells and renal tubular cells. GLUT 5 is a sucrose transporter in enterocytes. SGLT- Sodium-dependent glucose cotransporter or sodium-glucose linked transporter are a family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine and SGLT2 in the proximal tubule of the nephron.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 51
Incorrect
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Where is the normal upper border of the liver situated?
Your Answer: 3rd rib midclavicular line on right
Correct Answer: 6th rib midclavicular 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 52
Correct
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Which of the following runs in the upper part of the falx cerebri?
Your Answer: Superior sagittal sinus
Explanation:Falx cerebri is a sickle cell fold of dura between the two hemispheres. Its posterior part blends with the superior part of the tentorium cerebelli. The superior sagittal sinus runs in its upper fixed margin, the inferior sagittal sinus in the free concave margin and the straight sinus along its attachment to the tentorium cerebelli.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 53
Incorrect
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What is the function of the pro-apoptotic Bcl-2 family of proteins, Bax and Bak?
Your Answer: Cleaves DNA in the nucleus
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 54
Correct
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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: 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 55
Correct
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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 56
Correct
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According to Poiseuille’s formula, which 1 of the following will lead to increased flow?
Your Answer: Shorter tube
Explanation:V = π p r4 / 8 η lwhere V = discharge volume flow (m3/s)p = pressure difference between the ends of the pipe (N/m2, Pa)r = internal radius of pipe (m)l = length of pipe (m)η = viscosity of fluid
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 57
Correct
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Choose the correct answer: The cerebrocerebellum…
Your 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 58
Correct
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Question 59
Correct
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Which lipoprotein contains the most cholesterol esters?
Your 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 60
Incorrect
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In the malaria life cycle , parasites which remain dormant in the liver are known as :
Your Answer: Merozoites
Correct Answer: Hypnozoites
Explanation:The life-cycles of Plasmodium species involve several different stages both in the insect and the vertebrate host. These stages include sporozoites, which are injected by the insect vector into the vertebrate host’s blood. Sporozoites infect the host liver, giving rise to merozoites and (in some species) hypnozoites. These move into the blood where they infect red blood cells. In the red blood cells, the parasites can either form more merozoites to infect more red blood cells, or produce gametocytes which are taken up by insects which feed on the vertebrate host. In the insect host, gametocytes merge to sexually reproduce. After sexual reproduction, parasites grow into new sporozoites, which move to the insect’s salivary glands, from which they can infect a vertebrate host bitten by the insect
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 61
Correct
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In the gastric mucosa, which of the following cells is known to secrete gastric lipase?
Your Answer: Chief cell
Explanation:Chief cells produce pepsinogen and gastric lipase. Parietal cells produce stomach acid and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 62
Correct
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During which stage of sleep is muscle tone in the limbs most reduced?
Your Answer: REM
Explanation:Rapid eye movement (REM) stage is marked by extensive physiological changes in the body, such as accelerated respiration, increased brain activity and muscle relaxation. People dream during REM sleep, perhaps as a result of excited brain activity and the paralysis of major voluntary muscles.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 63
Correct
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The pathogen in variant Creutzfeldt Jacobs disease is an example of a:
Your Answer: Prion
Explanation:Types of Creutzfeldt Jacobs Disease (CJD) include:1. variant – This is thought to be caused by the consumption of food contaminated with prions, which also cause BSE.2. sporadic – This accounts for 85% of cases of CJD. 3. familial – This accounts for the majority of the other 15% cases of CJD.4. iatrogenic – This form of CJD arises from contamination with tissue from an infected person, usually as the result of a medical procedure.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 64
Correct
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The consensual light reflex is co-ordinated mainly in the:
Your Answer: Edinger-Westphal nucleus
Explanation:The consensual light reflex occurs when an individual’s right eye is shielded and light shines into the left eye, constriction of the right pupil will occur, as well as the left. This is because the afferent signal sent through one optic nerve connects to the Edinger-Westphal nucleus, whose axons run to both the right and the left oculomotor nerves.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 65
Correct
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The T-tubular system in cardiac muscle is:
Your Answer: Transmits action potential from sarcolemma to the SR to allow for Ca2+ release into the cytoplasm
Explanation:Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ from the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors, which are voltage gated calcium channels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 66
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 67
Correct
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Which of the following portocaval anastomoses can cause problems in preterm infants?
Your Answer: Patent ductus venosus.
Explanation:The ductus venosus is open at the time of the birth and closes during the first week of life in most full-term neonates; however, it may take much longer to close in pre-term neonates. After it closes, the remnant is known as ligamentum venosum. If the ductus venosus fails to occlude after birth, it remains patent (open), and the individual is said to have a patent ductus venosus and thus an intrahepatic portosystemic shunt (PSS).
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 68
Correct
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The following occurs as a result of 2,3 Bisphosphoglycerate binding to deoxyhaemoglobin
Your Answer: A reduction in deoxyhaemoglobin's affinity for oxygen
Explanation:2,3-BPG acts as a heteroallosteric effector of haemoglobin, lowering haemoglobin’s affinity for oxygen by binding preferentially to deoxyhaemoglobin. An increased concentration of BPG in red blood cells favours formation of the T, low-affinity state of haemoglobin and so the oxygen-binding curve will shift to the right.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 69
Correct
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A 74 year old man presents with 12 kg weight loss and persistent back pain that is unrelated to activity for the past several months. Laboratory findings show :WCC: 6.7 x 109/l (5.4 neutrophils, 1.2 lymphocytes and 0.2 monocytes)Haemoglobin: 11.2 g/dlhaematocrit: 33.3%MCV: 88 flPlatelet count: 89 x 109/l.The biochemistry shows:sodium 144 mmol/lpotassium 4.5 mmol/lchloride 100 mmol/lbicarbonate 26 mmol/lurea 14 mmol/lcreatinine 90 μmol/la glucose of 5.4 mmol/l.A CT scan of the spine reveals scattered 0.4 to 1.2 cm bright lesions in the vertebral bodies.Which of the following additional laboratory test findings is he most likely to have?
Your Answer: Serum prostate specific antigen of 35 microgram/l
Explanation:Old age, persistent backache, weight loss, and osteosclerotic lesions make prostatic adenocarcinoma the most likely diagnosis. The sequelae include severe pain, pathological fractures, hypercalcemia and cord compression. Prostatic adenocarcinoma is detected by elevated levels of prostate specific antigen. Positive serology for borrelia burgdorferi would hint at Lyme disease which does not cause osteosclerotic bone lesions, neither would Neisseria gonorrhoeae have such a presentation.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 70
Correct
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What is the function of the macula densa, located in the wall of the thick ascending limb?
Your Answer: Tubuloglomerular feedback.
Explanation:Macula densa cells sense changes in sodium chloride level, and will trigger an autoregulatory response to increase or decrease reabsorption of ions and water to the blood (as needed) in order to alter blood volume and return blood pressure to normal. Tubuloglomerular feedback is one of several mechanisms the kidney uses to regulate glomerular filtration rate (GFR). It involves the concept of purinergic signalling, in which an increased distal tubular sodium chloride concentration causes a basolateral release of adenosine from the macula densa cells. This initiates a cascade of events that ultimately brings GFR to an appropriate level.
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This question is part of the following fields:
- Medicine
- Renal
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Question 71
Correct
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Which of the following factors is most likely to lead to an increase in serum cortisol levels?
Your 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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Question 72
Correct
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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: 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 73
Incorrect
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Which is NOT a prognostic factor for patients with malignant melanoma?
Your Answer: Microsatellite metastasis
Correct Answer: Diameter of melanoma > 6 mm
Explanation:Features that affect prognosis are tumour thickness in millimetres (Breslow’s depth – the deeper the Breslow thickness the poorer the prognosis.), depth related to skin structures (Clark level – the level of invasion through the dermis), type of melanoma, presence of ulceration, presence of lymphatic/perineural invasion, presence of tumour-infiltrating lymphocytes (if present, prognosis is better), location of lesion, presence of satellite lesions, and presence of regional or distant metastasis. Malignant melanoma tends to grow radially before entering a vertical growth phase. The diameter it reaches has not been found to be a prognostic factor.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 74
Correct
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If both the noradrenergic and the cholinergic systems are blocked in the heart, the rate will be approximately:
Your Answer: 100/min
Explanation:The normal heart beat is about 70/min. This is due to a predominant parasympathetic activity. If sympathetic activity was unopposed the heart rate would have been 150/min. When both the noradrenergic and cholinergic systems are blocked the heart rate is 100/min. This is the normal firing rate of the SA node.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 75
Correct
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What is the function of Activated protein C?
Your Answer: Inactivates factor Va
Explanation:Activated Protein C (APC) is a crucial protein in the regulation of blood coagulation. Its primary functions include:
- Inactivating Factor Va: APC inactivates Factor Va, which is a cofactor for the conversion of prothrombin to thrombin by Factor Xa. By inactivating Factor Va, APC reduces thrombin formation, thereby acting as an anticoagulant.
- Inactivating Factor VIIIa: APC also inactivates Factor VIIIa, another cofactor that assists Factor IXa in the conversion of Factor X to Factor Xa. This further contributes to its anticoagulant effect.
These actions help to regulate blood clotting and prevent excessive thrombosis.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 76
Correct
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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 77
Incorrect
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A clinical trial is conducted to study the benefits of a new oral medication to improve the symptoms of patients with asthma. In the trial 400 patients with asthma, half were given the new medication and half a placebo. Three months later they are asked to rate their symptoms using the following scale: much improved, slight improvement, no change, slight worsening, significantly worse. What is the most appropriate statistical test to see whether the new medication is beneficial?
Your Answer: Chi-squared test
Correct Answer: Mann-Whitney U test
Explanation:The type of significance test used depends on whether the data is parametric (can be measured, usually normally distributed) or non-parametric.Parametric tests:Student’s t-test – paired or unpaired*Pearson’s product-moment coefficient – correlationNon-parametric tests:Mann-Whitney U test – unpaired dataWilcoxon signed-rank test – compares two sets of observations on a single samplechi-squared test – used to compare proportions or percentagesSpearman, Kendall rank – correlation.The outcome measured is not normally distributed, i.e. it is non-parametric. This excludes the Student’s t-tests. We are not comparing percentages/proportions so the chi-squared test is excluded. The Mann–Whitney U test is a nonparametric test of the null hypothesis that it is equally likely that a randomly selected value from one sample will be less than or greater than a randomly selected value from a second sample.This test can be used to investigate whether two independent samples were selected from populations having the same distribution.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 78
Correct
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On which presynaptic receptor does noradrenalin act to inhibit noradrenalin secretion?
Your Answer: Α2 receptor
Explanation:Adregenic receptors are A1, A2, B1, B2, B3. Out of these, the function of the A2 receptor is inhibition of transmitter release including nor adrenalin and acetylcholine of the autonomic nervous system.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 79
Correct
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A 20-year-old male presents to the emergency department about 4 hours after ingesting 20g of paracetamol. N-acetyl cysteine was started immediately. What is the mechanism of action of N-acetyl cysteine?
Your Answer: Replenishes glutathione
Explanation:N-acetylcysteine depletes glutathione reserves by providing cysteine, which is an essential precursor in glutathione production.Glutathione within the liver can normally detoxify these minuscule quantities of NAPQI and prevent tissue damage.N-acetylcysteine (NAC) is the mainstay of therapy for acetaminophen toxicity.Paracetamol overdose:The liver normally conjugates paracetamol with glucuronic acid/sulphate. During an overdose, the conjugation system becomes saturated leading to oxidation by cytochrome P450 (predominately CYP2E1) mixed-function oxidases. This produces a toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI).Normally glutathione acts as a defence mechanism by conjugating with the toxin forming the non-toxic mercapturic acid. If glutathione stores run-out, the toxin forms covalent bonds with cell proteins, denaturing them and leading to cell death.Other uses: In COPD, cystic fibrosis, and other lung conditions, nebulized NAC has mucolytic, anti-inflammatory, and antioxidant properties.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 80
Correct
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Which statement regarding fever is correct:
Your Answer: Body temperature is regulated is by a centre in the floor of the third ventricle
Explanation:The hypothalamus is located on the floor of the third ventricle and is the centre of regulation of body temperature. It uses a set point to regulate other body systems as well. Diurnal variation of temperature is not seen in humans. the principal mediator of fever is interleukin I, although interferon alfa also plays a role. Fever can cause rhabdomyolysis or muscle breakdown
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 81
Correct
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Which one of the following makes up most of the adrenal cortex?
Your Answer: Zona fasciculata
Explanation:The zona fasciculata represents the widest area of the adrenal cortex, situated in the middle of the cortex. It produces glucocorticoids including; 11-deoxycorticosterone, corticosterone, and cortisol.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 82
Incorrect
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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: 2n
Correct 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 83
Correct
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A 33-year-old electrical technician presents following an overdose. Anticholinergic syndrome is suspected. Which of the following is true?
Your Answer: Mydriasis occurs
Explanation:Anticholinergic syndrome occurs following overdose with drugs that have prominent anticholinergic activity including tricyclic antidepressants, antihistamines and atropine. Features include dry, warm, flushed skin, urinary retention, tachycardia, mydriasis (dilated pupils) and agitation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 84
Correct
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Regarding carbohydrates absorption;
Your 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 85
Incorrect
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A 76-year-old man has been admitted with a respiratory tract infection. On examination, he was found to be confused and dyspnoeic with O2 saturation of 88%. He has a 60 pack-year smoking history. An arterial blood gas analysis reveals CO2 retention. He has been deemed unfit for admission into the intensive care unit. The physician elects to begin a doxapram infusion. Among the following statements which best fits with the characteristics of doxapram?
Your Answer: Hypotension is a commonly seen side effect
Correct Answer: Epilepsy is a contraindication for doxapram use
Explanation:The statement that fits the characteristics of doxapram is, epilepsy is a contraindication for doxapram use. Concurrent use with theophylline may increase agitation not relaxation.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 86
Correct
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Microtubule disassembly:
Your Answer: Occurs at the positive and negative end
Explanation:Dynamic instability refers to the coexistence of assembly and disassembly at the ends of a microtubule. The microtubule can dynamically switch between growing and shrinking phases in this region. Although both assembly and disassembly occur at both ends they occur preferentially at the (+) end.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 87
Correct
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Which of the following are responsible for the 4th heart sound?
Your Answer: Ventricular hypertrophy
Explanation:The fourth heart sound is not normally audible in a normal adult. It occurs as a consequence of ventricular hypertrophy. It is caused by filling of the ventricle in atrial systole.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 88
Incorrect
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Which of the following conditions is NOT X-linked recessive?
Your Answer: Complete testicular feminisation
Correct Answer: Cystic fibrosis
Explanation:Cystic fibrosis is a autosomal recessive disease with an incidence of about 1 in 2500 live births. The most common mutation occurs in the long arm of chromosome 7 which codes for the chloride channel (cystic fibrosis transmembrane conductance regulator) gene.
To have CF, a child must inherit two abnormal genes—one from each parent. The recessive CF gene can occur in both boys and girls because it is located on non-sex-linked chromosomes called autosomal chromosomes.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 89
Correct
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With regard to carbohydrate absorption, which sodium-dependent glucose transporter (SGLT) is responsible for the uptake of dietary glucose from the gut?
Your Answer: SGLT 1
Explanation:SGLT- Sodium-dependent glucose cotransporter or sodium-glucose linked transporter are family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 90
Incorrect
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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: Collagen
Correct 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 91
Correct
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Question 92
Incorrect
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High titre of which of the following antibodies is not considered diagnostic for the mentioned disease?
Your Answer: Anti-centromere antibodies in limited systemic sclerosis
Correct Answer: Rheumatoid factor in rheumatoid arthritis (RA)
Explanation:Diagnosis of RA is mainly based on clinical features (e.g., morning stiffness, symmetrical joint swelling) and laboratory tests (e.g., anti-CCP). Rheumatoid factor is not very specific for this disease and hence has low reliability. X-ray findings (e.g., soft tissue swelling or joint space narrowing) occur late in the disease and are therefore not typically used for diagnosis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 93
Correct
-
Where does the pituitary gland lie?
Your Answer: In a pocket of the sphenoid bone at the base of the brain
Explanation:The pituitary lies in a small depression in the sphenoid bone, known as the sella turcica or Turkish saddle.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 94
Correct
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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 95
Correct
-
Activation of baroreceptor reflex involves:
Your Answer: Short term regulation of systemic blood pressure
Explanation:Baroreceptors are found in the heart and the blood vessels. They are the carotid sinus and the aortic arch receptors and respond to the minute to minute change in the blood pressure i.e. a change in the pulsatile pressure and not to a change in the mean arterial pressure. If the pulse pressure decreases, the rate of firing of the receptors decreases, stimulating an increase in the heart rate and blood pressure. Mechanisms that regulate the long term blood pressure control include the renin-angiotensin-aldosterone mechanism.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 96
Incorrect
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What is the rationale concerning the use of sodium cromoglycate in the prophylaxis of bronchial asthma?
Your Answer: Competitive blockade of histamine at receptor sites
Correct Answer: Inhibition of mast-cell degranulation
Explanation:Sodium cromoglycate principally acts by inhibiting the degranulation of mast cells triggered by the interaction of antigen and IgE. The inhibitory effect on mast cells appears to be cell-type specific since cromoglycate has little inhibitory effect on mediator release from human basophils.Thus, it inhibits the release of histamine, leukotrienes, and slow-reacting substance of anaphylaxis from mast cells by inhibiting degranulation following exposure to reactive antigens.Adverse effects include cough, flushing, palpitation, chest pain, nasal congestion, nausea, fatigue, migraine, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 97
Incorrect
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Question 98
Correct
-
Which of the following concerning PR interval is INCORRECT?
Your Answer: Always measured from the beginning of p wave to the beginning of r wave
Explanation:The PR interval measures the time from the start of atrial depolarization to the start of ventricular depolarization. The PR interval is only measured from the beginning of P wave to beginning of R wave if the Q wave is absent.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 99
Correct
-
Bronchial smooth muscle:
Your Answer: Tone is increased by cholinergic discharge
Explanation:The lungs are supplied by both the sympathetic and parasympathetic divisions of the autonomic nervous system. The parasympathetic innervation is supplied by the vagus nerve. The parasympathetic nervous system is the dominant neuronal pathway in the control of airway smooth muscle tone. Stimulation of cholinergic nerves causes bronchoconstriction, mucus secretion, and bronchial vasodilation. Sympathetic innervation is supplied by the T1 to T5 of the spinal cord and act mainly via beta adrenergic receptors. Stimulation of the sympathetic nervous system causes vasoconstriction and bronchodilation.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 100
Correct
SESSION STATS - PERFORMANCE PER SPECIALTY
