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Question 1
Incorrect
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Hydroxyl radicals are broken down by which of the following substance?
Your Answer: Hydroxyl dismutase
Correct Answer: Antioxidants
Explanation:Unlike superoxide, which can be detoxified by superoxide dismutase, the hydroxyl radical cannot be eliminated by an enzymatic reaction but it is believed can be counteracted by antioxidants.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 2
Correct
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Cyclic AMP activates the following enzyme
Your Answer: Protein Kinase A
Explanation:Cyclic AMP works by activating protein kinase A (PKA, or cAMP-dependent protein kinase). Protein kinase A can also phosphorylate specific proteins that bind to promoter regions of DNA, causing increases in transcription.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 3
Correct
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The interventricular septum is supplied anteriorly by the?
Your Answer: Left anterior descending artery
Explanation:The anterior interventricular artery or left anterior descending artery supplies the anterior 2/3rds of the interventricular septum.
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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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Activation of the cool receptor (CMR-1), causes:
Your Answer: Influx of Ca++ & Na+
Explanation:Cold and Menthol receptor 1 (CMR1) is a protein that in humans is encoded by TRPM8 gene. It is an ion channel which upon activation causes the influx of Na+ and Ca++ ions into the cell that leads to the depolarization and generation of an action potential.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 5
Incorrect
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The thalamic main input from the cortex is via which tracts?
Your Answer: Corticospinal tracts
Correct Answer: Thalamocortical pathway
Explanation:The thalamus is connected to cerebral cortex via the thalamocortical radiation.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 6
Correct
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The isoforms of nitric oxide synthase which are found in the nervous system (NOS1) and endothelial cells (NOS3) are activated by agents that increase which of the following intracellular electrolytes?
Your Answer: Ca
Explanation:Synthesis of nitric oxide is stimulated by activation of the NMDA receptors by certain agents. This leads to opening of the Calcium channels and an influx of calcium into the cell. This will activate the nitric oxide synthase. Nitric oxide is produced on demand.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 7
Correct
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The Cellular Theory of Ageing involves?
Your Answer: Loss of telomeres
Explanation:Cellular theories of aging propose that human aging is the result of cellular aging, whereby an increasing proportion of cells reach senescence, a terminal stage at which cells will cease to divide. This will limit the body’s ability to regenerate and to respond to injury or stress. Telomeres are bits of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling, which could cause DNA to abnormally function. As cells replicate, telomeres shorten at the end of chromosomes, and this process correlates to senescence or cellular aging.
Other theories include:
- The Free Radical Theory: Implicates the gradual accumulation of oxidative cellular damage as a fundamental driver of cellular aging. This theory has evolved over time to emphasize the role of free radical induced mitochondrial DNA (mtDNA) mutations and the accumulation of mtDNA deletions. Given the proximity of mtDNA to the electron transport chain, a primary producer of free radicals, it postulates that the mutations would promote mitochondrial dysfunction and concomitantly increase free radical production in a positive feedback loop. It is known that diet, lifestyle, drugs (e.g. tobacco and alcohol) and radiation etc., are all accelerators of free radical production within the body.
- Error theory: based on the idea that errors can occur in the transcription of the synthesis of DNA. These errors are perpetuated and eventually lead to systems that do not function at the optimum level. The organism’s aging and death are attributable to these events (Sonneborn, 1979).
- The Cross-Linking Theory: also referred to as the Glycosylation Theory of Aging. In this theory it is the binding of glucose (simple sugars) to protein, (a process that occurs under the presence of oxygen) that causes various problems. Once this binding has occurred the protein becomes impaired and is unable to perform as efficiently. Living a longer life is going to lead to the increased possibility of oxygen meeting glucose and protein and known cross-linking disorders include senile cataract and the appearance of tough, leathery and yellow skin.
- The Neuroendocrine Theory First proposed by Professor Vladimir Dilman and Ward Dean MD, this theory elaborates on wear and tear by focusing on the neuroendocrine system. This system is a complicated network of biochemicals that govern the release of hormones which are altered by the walnut sized gland called the hypothalamus located in the brain. The hypothalamus controls various chain-reactions to instruct other organs and glands to release their hormones etc. The hypothalamus also responds to the body hormone levels as a guide to the overall hormonal activity. But as we grow older the hypothalamus loses it precision regulatory ability and the receptors which uptake individual hormones become less sensitive to them. Accordingly, as we age the secretion of many hormones declines and their effectiveness (compared unit to unit) is also reduced due to the receptors down-grading
- The Membrane Theory of Aging: According to this theory it is the age-related changes of the cell’s ability to transfer chemicals, heat and electrical processes that impair it. As we grow older the cell membrane becomes less lipid (less watery and more solid). This impedes its efficiency to conduct normal function and in particular there is a toxic accumulation
- The Decline Theory: The mitochondria are the power producing organelles found in every cell of every organ. Their primary job is to create Adenosine Triphosphate (ATP) and they do so in the various energy cycles that involve nutrients such as Acetyl-L-Carnitine, CoQ10 (Idebenone), NADH and some B vitamins etc. Enhancement and protection of the mitochondria is an essential part of preventing and slowing aging. Enhancement can be achieved with the above mention nutrients, as well as ATP supplements themselves.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 8
Correct
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The functional unit of the liver is called?
Your Answer: Acini
Explanation:From a metabolic perspective, the functional unit is the hepatic acinus (terminal acinus), each of which is centred on the line connecting two portal triads and extends outwards to the two adjacent central veins. The periportal zone I is nearest to the entering vascular supply and receives the most oxygenated blood, making it least sensitive to ischemic injury while making it very susceptible to viral hepatitis. Conversely, the centrilobular zone III has the poorest oxygenation, and will be most affected during a time of ischemia.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 9
Correct
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Question 10
Correct
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Cell membrane proteins may act as:
Your Answer: All of the options
Explanation:Membrane proteins perform a variety of functions including:Membrane receptor proteins relay or carry signals between the cell’s internal and external environments.Transport proteins move molecules and ions (ionic channels) across the membrane. Membrane enzymes may have many activities, such as oxidoreductase, transferase or hydrolase andCell adhesion molecules
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 11
Incorrect
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Which of the following is not a cause of drug-induced hepatitis?
Your Answer: Amiodarone
Correct Answer: Ethambutol
Explanation:Although rare, ocular toxicity in the form of optic neuritis (most commonly retrobulbar neuritis) has been well documented as a side effect of ethambutol. It is renally excreted and not associated with hepatitis.
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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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Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of the ventricular muscle fibers?
Your Answer: Potassium channels
Explanation:Depolarization occurs due to opening of the voltage gated sodium channels. Repolarization occurs due to opening of the voltage gates potassium channels causing an out flux of potassium ions, decreasing the membrane potential towards resting potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Correct
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Where are the baroreceptors of the great arteries located?
Your Answer: In the adventitia
Explanation:Arterial baroreceptors are located in the aortic arch and carotid sinuses, and are formed by small nerve endings present in the adventitia of these vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 14
Correct
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Which neuron secretes glutamate as its neurotransmitter?
Your Answer: A delta and C pain fibers
Explanation:A delta and C fibers use glutamate as their primary neurotransmitter where it acts as a fast acting localized neurotransmitter.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 15
Incorrect
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In the menstrual cycle, ovulation is triggered by:
Your Answer: A pituitary LH surge due to due to an increase in GNRH pulses from the supraoptic nucleus in the hypothalamus
Correct Answer: A pituitary LH surge due to the positive feedback effect of circulating oestrogens
Explanation:FSH and LH are secreted to start the development of a follicle at the start of each menstrual cycle. A surge in oestrogen causes a positive feedback in the LH cells of the pituitary; this causes ovulation.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 16
Incorrect
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A 26-year-old student has been brought to the emergency department in a confused state. His friends report that he has been complaining of headaches for the past few weeks. He has a low-grade fever and on examination is noted to have abnormally pink mucosa. What is the most likely diagnosis?
Your Answer: Meningitis
Correct Answer: Carbon monoxide poisoning
Explanation:Confusion and pink mucosae are typical features of CO poisoning.The patient often presents, most commonly with headaches, and other symptoms like malaise, nausea, and dizziness.Carbon monoxide (CO) poisoning, considered as the great imitator of other diseases as the patients present with a myriad of symptoms. The carbon monoxide diffuses rapidly across the pulmonary capillary membrane binding to the haem molecule with a very high affinity (240 times that of oxygen) forming carboxy-haemoglobin (COHb). Non-smokers have a baseline COHb of ,3% while smokers have a baseline COHb of 10-15%.Features of carbon monoxide toxicity- Headache: 90% of cases- Nausea and vomiting: 50%- Vertigo: 50%- Confusion: 30%- Subjective weakness: 20%- Severe toxicity: ‘pink’ skin and mucosae, hyperpyrexia, arrhythmias, extrapyramidal features, coma, deathTreatment:Use of Hyperbaric oxygen therapy (HBOT) for treating mild to moderate CO poisoning is not routine.The selection criteria for HBOT in cases of CO poisoning include:• COHb levels > 20-25%• COHb levels > 20% in pregnant patient • Loss of consciousness• Severe metabolic acidosis (pH <7.1)• Evidence of end-organ ischemia (e.g., ECG changes, chest pain, or altered mental status)
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 17
Incorrect
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Which of the following with regard to DNA mutations does not fit:
Your Answer: All of them fit
Correct Answer: All gene mutations cause clinical disease entities
Explanation:All gene mutations do not cause a clinical manifestation of the disease, some gene mutations are silent mutations. They are present but do not cause any disease.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 18
Incorrect
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Which of the following conditions is associated with eosinophilia?
Your Answer: Long-term corticosteroid use
Correct Answer: Ascaris
Explanation:Eosinophilia can be idiopathic (primary) or, more commonly, secondary to another disease. In the Western World, allergic or atopic diseases are the most common causes, especially those of the respiratory or integumentary systems. In the developing world, parasites are the most common cause e.g. Ascaris
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This question is part of the following fields:
- Haematology
- Medicine
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Question 19
Incorrect
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Pacemaker cells in the SA node and the AV node are connected by?
Your Answer: P cells
Correct Answer: Gap junctions
Explanation:Gap junctions allows for rapid propagation of the action potential from one cell to the other. The cells of the heart are connected by gap junctions.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 20
Incorrect
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The midbrain, medulla and pons, contain the following cranial nerve nuclei?
Your Answer: CN 5 – 12
Correct Answer: CN 3 - 12
Explanation:The cranial nerves (with the exception of I and II) originate in the brainstem, which includes the midbrain, the pons, and the medulla.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 21
Incorrect
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Which hormone secreting cell of the human anterior pituitary gland secretes growth hormone?
Your Answer: Corticotrope
Correct Answer: Somatotroph
Explanation:Somatotroph cells are responsible for the production of growth hormone. Somatotrophs occupy nearly 40% of the total surface area of the anterior pituitary, and they are acidophilic in nature.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 22
Correct
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Transport of Iron into enterocytes occurs via which membrane transporter?
Your Answer: Divalent metal transporter 1(dmt1)
Explanation:To be absorbed, dietary iron can be absorbed as part of a protein such as haem protein or iron must be in its ferrous Fe2+ form. A ferric reductase enzyme on the enterocytes’ brush border, duodenal cytochrome B (Dcytb), reduces ferric Fe3+ to Fe2+. A protein called divalent metal transporter 1 (DMT1), which can transport several divalent metals across the plasma membrane, then transports iron across the enterocyte’s cell membrane into the cell.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 23
Incorrect
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A 82-year-old woman admitted following a fractured neck of femur has been discharged. On review, she is making good progress but consideration is given to secondary prevention of further fractures. What is the most appropriate step in the prevention of further fractures?
Your Answer: Arrange DEXA scan + start strontium ranelate if T-score < -2.5 SD
Correct Answer: Start oral bisphosphonate
Explanation:In such a clinical scenario, NICE guidelines support initiating treatment with bisphosphonates without waiting for a DEXA scan.Osteoporosis is defined as low bone mineral density caused by altered bone microstructure ultimately predisposing patients to low-impact, fragility fractures.Management:Vitamin D and calcium supplementation should be offered to all women unless the clinician is confident they have adequate calcium intake and are vitamin D repleteAlendronate is the first-line treatment. Around 25% of patients cannot tolerate alendronate, usually due to upper gastrointestinal problems. These patients should be offered risedronate or etidronate.Strontium ranelate and raloxifene are recommended if patients cannot tolerate bisphosphonates.Other medications that are useful in the treatment of osteoporosis are denosumab, teriparatide, raloxifene, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 24
Correct
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Question 25
Incorrect
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Which of the following tracts are involved in the control of vital functions?
Your Answer: Spinothalamic
Correct Answer: Reticulospinal
Explanation:Reticulospinal tract pass down from the reticular formation of the mid brain, pons and medulla. It descends in the lateral white column. Both sets of fibers enter the anterior grey column and may facilitate or inhibit the gamma and alpha neurons. By this means the reticulospinal tract controls voluntary and reflex activities. It also contains the descending autonomic fiber, thus providing a pathway for the hypothalamus to control the sympathetic and parasympathetic pathways.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 26
Correct
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Where is angiotensinogen produced?
Your Answer: Liver
Explanation:Angiotensin is a peptide hormone that causes vasoconstriction and a subsequent increase in blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex. Aldosterone promotes sodium retention in the distal nephron, in the kidney, which also drives blood pressure up. It is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver.
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This question is part of the following fields:
- Medicine
- Renal
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Question 27
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 28
Correct
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Which three parietal cell agonists bind at the basolateral membrane at specific receptors respectively: M3 , H2 , CCK-B, to stimulate acid secretion?
Your Answer: Acetylcholine, histamine , gastrin
Explanation:The three agonists of parietal cell secretion are gastrin, acetylcholine and histamine. Parietal cells are responsible for the secretion of HCl and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 29
Correct
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When observing a JVP, which of the following would lead to prominent v waves?
Your Answer: Tricuspid regurgitation
Explanation:The v wave corresponds to Venous filling when the tricuspid valve is closed and venous pressure increases from venous return. In Tricuspid regurgitation there is additional blood from the regurgitant flow and thus this leads to a more prominent V wave.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 30
Incorrect
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Which one of the following is most likely to be seen in a patient with multiple endocrine neoplasia (MEN) type I?
Your Answer: Pheochromocytoma
Correct Answer: Insulinoma
Explanation:Multiple endocrine neoplasia type 1 (MEN-1 syndrome) or Wermer’s syndrome is part of a group of disorders, the multiple endocrine neoplasias, that affect the endocrine system through development of neoplastic lesions in the ‘three P’s’:Parathyroid (>90%): hyperparathyroidism due to parathyroid hyperplasiaPituitary (15-42%)Pancreas (60-70%, e.g. insulinoma, gastrinoma)
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This question is part of the following fields:
- Endocrinology
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
