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Question 1
Correct
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The chest X-ray of a 72 year old patient reveals the presence of a round lesion containing an air-fluid level in the left lung. These findings are most probably suggestive of:
Your Answer: Lung abscess
Explanation:Lung abscesses are collections of pus within the lung that arise most commonly as a complication of aspiration pneumonia caused by oral anaerobes. Older patients are more at risk due to poor oral hygiene, gingivitis an inability to handle their oral secretions due to other diseases. Chest X-ray most commonly reveals the appearance of an irregularly shaped cavity with an air-fluid level.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 2
Incorrect
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A patient is diagnosed with Conn’s syndrome. Aldosterone is secreted from where?
Your Answer: Juxtaglomerular apparatus
Correct Answer: Zona glomerulosa of the adrenal cortex
Explanation:The adrenal gland comprises an outer cortex and an inner medulla, which represent two developmentally and functionally independent endocrine glands.
The adrenal medulla secretes adrenaline (70%) and noradrenaline (30%)
The adrenal cortex consists of three layers (remembered by the mnemonic GFR):
G = zona glomerulosa – secretes aldosterone
F = zona fasciculata – secretes cortisol and sex steroids
R = zona reticularis – secretes cortisol and sex steroids.
Aldosterone facilitates the reabsorption of sodium and water and the excretion of potassium and hydrogen ions from the distal convoluted tubule and collecting ducts. Conn’s syndrome is characterized by increased aldosterone secretion from the adrenal glands. -
This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 3
Correct
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Which lymph nodes are most likely to enlarge due to the spread of infection through the lymphatic channels in a patient with a boil on his scrotum?
Your Answer: Superficial inguinal nodes
Explanation:The superficial inguinal nodes drain the perineum and the external genitalia which include the scrotum and the labia majora. The testes, however, drain to the lumbar nodes.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 4
Incorrect
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A 35-year old lady presents to her GP with vague abdominal symptoms. Examination reveals a normal size spleen. Which of the following is the likely diagnosis?
Your Answer: Myelofibrosis
Correct Answer: Idiopathic thrombocytopenic purpura
Explanation:Idiopathic thrombocytopenic purpura (ITP) is a disease caused due to development of an antibody against a platelet antigen (autoantibody). In childhood disease, the autoantibody gets triggered by binding of viral antigen to the megakaryocytes. Presentation includes unexplained thrombocytopenia, petechiae and bleeding from mucosal surfaces. The spleen usually does not enlarge in size. However, splenomegaly can occur due to coexisting viral infection. Marrow examination reveals normal or increased number of megakaryocytes. Diagnosis is by exclusion of other thrombocytopenic disorders.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 5
Correct
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A 90-year-old man is prescribed spironolactone after his family notices his legs are swollen. What class of drugs does spironolactone belong to?
Your Answer: Potassium-sparing diuretics
Explanation:Spironolactone is a renal competitive aldosterone antagonist in a class of drugs called ‘potassium-sparing diuretics’, that is primarily used to treat fluid build-up due to heart failure, liver scarring, or kidney disease. It is also used in the treatment of high blood pressure, low blood potassium, early-onset puberty, and acne and excessive hair growth in women. Spironolactone inhibits the effect of aldosterone by competing for intracellular aldosterone receptors in the distal tubule cells. This increases the secretion of water and sodium, while decreasing the excretion of potassium.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 6
Correct
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Which of the following changes in the histology of the cell is most likely to be accompanied by disruption of the cell membrane following an injury?
Your Answer: Coagulative necrosis
Explanation:The process of necrosis ends with the rupture of the cell membrane and the consequent release of the cellular components into the surrounding tissue. Apoptosis, pyknosis and karyorrhexis are not reversible events but the cell membrane remains intact. Cloudy swelling and hydropic changes are also reversible but again the cell membrane remains intact and they are therefore different and distinct from necrosis.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 7
Incorrect
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Which of the following organs of the abdominal cavity is completely covered by the peritoneum?
Your Answer: Inferior vena cava
Correct Answer: Spleen
Explanation:Of the organs listed, the spleen is the only organ that is completely intraperitoneal, that is entirely in the peritoneum. Other completely intraperitoneal organs include the stomach, liver, appendix and the small intestines. The kidney, Inferior vena cava, aorta and the suprarenal glands are all retroperitoneal organs. The pancreas and the duodenum are partially retroperitoneal, with the tail of the pancreas in the peritoneum found in the splenorenal ligament while only the first part of the duodenum is intraperitoneal. For the intraperitoneal organs remember SALTD SPRSS
S = Stomach
A = Appendix
L = Liver
T = Transverse colon
D = Duodenum (only the 1st part)S = Small intestines
P = Pancreas (only the tail)
R = Rectum (only the upper 3rd)
S = Sigmoid colon
S = SpleenFor retroperitoneal, just remember SADPUCKER:
S = suprarenal glands
A = Aorta and IVC
D = Duodenum (all but the 1st part)
P = Pancreas (all but the tail)
U = Ureter and bladder
C = Colon (ascending and descending)
K = Kidneys
E = Oesophagus
R = Rectum (Lower two-thirds)For secondarily retroperitoneal remember ‘Pussy Cat Dolls“:
P = Pancreas
C = Colon (only ascending and descending)
D = Duodenum (only parts 2-4) -
This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 8
Correct
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Electrophoresis is used to detect antibodies (immunoglobulins) in a blood sample from the umbilical artery of a new born. Which antibodies have the highest percentage in a new-born?
Your Answer: IgG
Explanation:IgG is a monomeric immunoglobulin. It is formed by two heavy chains and two light chains and has two binding sites. Its is the most abundant antibody that is equally distributed in the blood and the tissues. It is the only antibody that can pass through the placenta and thus the only antibody present in the baby after it is born. There are four subclasses: IgG1 (66%), IgG2 (23%), IgG3 (7%) and IgG4 (4%). IgG1, IgG3 and IgG4 cross the placenta easily
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 9
Correct
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A 16-year old boy was brought in an unconscious state to the emergency department. Clinical evaluation pointed in favour of acute adrenal insufficiency. On enquiry, it was revealed that he was suffering from a high grade fever 24 hours prior. On examination, extensive purpura were noted on his skin. The likely diagnosis is:
Your Answer: Meningococcaemia
Explanation:Findings described are suggestive of Waterhouse-Friderichsen syndrome which develops secondary to meningococcaemia. The reported incidence of Addison’s disease is 4 in 100,000. It affects both sexes equally and is seen in all age groups. It tends to show clinical symptoms at the time of metabolic stress or trauma. The symptoms are precipitated by acute infections, trauma, surgery or sodium loss due to excessive perspiration.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 10
Correct
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During the fetal stage, the mesonephric tubules gives rise to the?
Your Answer: Wolffian duct
Explanation:The development of the kidney proceeds through a series of successive phases, each marked by the development of a more advanced kidney: the pronephros, mesonephros, and metanephros. The development of the pronephric duct proceeds in a cranial-to-caudal direction. As it elongates caudally, the pronephric duct induces nearby intermediate mesoderm in the thoracolumbar area to become epithelial tubules called mesonephric tubules. Each mesonephric tubule receives a blood supply from a branch of the aorta, ending in a capillary tuft analogous to the glomerulus of the definitive nephron. The mesonephric tubule forms a capsule around the capillary tuft, allowing for filtration of blood. This filtrate flows through the mesonephric tubule and is drained into the continuation of the pronephric duct, now called the mesonephric duct or Wolffian duct. The nephrotomes of the pronephros degenerate while the mesonephric duct extends towards the most caudal end of the embryo, ultimately attaching to the cloaca.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 11
Correct
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Which of the following structure contains the parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle?
Your Answer: Edinger–Westphal nucleus
Explanation:The Edinger–Westphal nucleus (accessory oculomotor nucleus) is the parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 12
Correct
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Pain in the epigastric region occurring typically 2-3 hours after meals and causing the patient to wake up at night is characteristic of which of the following conditions?
Your Answer: Duodenal ulcer
Explanation:The description is typical for duodenal ulcers. There is no pain upon waking in the morning however it appears around mid-morning and is relieved by ingestion of food. The pain also often causes the patient to wake up at night.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 13
Correct
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Which of the following foramen provides passage of the facial nerve?
Your Answer: Internal acoustic meatus
Explanation:The internal auditory meatus provides a passage through which the vestibulocochlear nerve, the facial nerve, and the labyrinthine artery (an internal auditory branch of the basilar artery) can pass from inside the skull to structures of the inner ear and face.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 14
Correct
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Two boys were playing when one of them brought the forearm of the other behind his back. This resulted in a stretching of the lateral rotator of the arm. Which of the following muscles was most likely to have been involved?
Your Answer: Infraspinatus
Explanation:There are two lateral rotators of the arm, the infraspinatus and the teres minor muscles. The infraspinatus muscle receives nerve supply from C5 and C6 via the suprascapular nerve, whilst the teres minor is supplied by C5 via the axillary nerve.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 15
Correct
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A drug abuser developed an infection which spread from the dorsum of the hand to the medial side of the arm along the course of the large cutaneous vein. Which vein is involved?
Your Answer: Basilic
Explanation:The basilic vein is one of two veins found in the forearm, the other is the cephalic vein. These veins originate from the deep venous arch of the hand. The cephalic vein ascends along the lateral side of the forearm, and the basilic vein runs up the medial side of the forearm.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 16
Correct
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A 17-year-old boy, who had developed shortness of breath and a loss of appetite over the last month, was referred to a haematologist because he presented with easy bruising and petechiae. His prothrombin time, platelet count, partial thromboplastin and bleeding time were all normal. Which of the following would explain the presence of the petechiae and easy bruising tendency?
Your Answer: Scurvy
Explanation:Scurvy is a condition caused by a dietary deficiency of vitamin C, also known as ascorbic acid. Humans are unable to synthesize vitamin C, therefore the quantity of it that the body needs has to come from the diet. The presence of an adequate quantity of vitamin C is required for normal collagen synthesis. In scurvy bleeding tendency is due to capillary fragility and not coagulation defects, therefore blood tests are normal.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 17
Correct
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Which organ is most vulnerable to haemorrhagic shock?
Your Answer: Kidneys
Explanation:At rest, the brain receives 15% cardiac output, muscles 15%, gastrointestinal tract 30% and kidneys receive 20%. However, if normalised by weight, the largest specific blood flow is received by the kidneys at rest (400 ml/min x 100g), making them highly vulnerable in the case of a haemorrhagic shock.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 18
Incorrect
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For calculation of cardiac output by Fick's principle, which of the following vessels is the best source of venous blood to determine the arterial-to-venous oxygen tension difference?
Your Answer: Jugular vein
Correct Answer: Pulmonary artery
Explanation:Fick’s principle states that the total uptake (or release) of a substance by peripheral tissues is equal to the product of the blood flow to the peripheral tissues and the arterial– venous concentration difference (gradient) of the substance. It is used to measure the cardiac output, and the formula is Cardiac output = oxygen consumption divided by arteriovenous oxygen difference. Assuming there are no shunts across the pulmonary system, the pulmonary blood flow equals the systemic blood flow. The arterial and venous blood oxygen content is measured by sampling from the pulmonary artery (low oxygen content) and pulmonary vein (high oxygen content). Peripheral arterial blood is used as a surrogate for the pulmonary vein.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 19
Correct
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A 50 year old woman presented with excessive bleeding after an inguinal hernia repair. Labs are suggestive of a primary haemostasis defect. Deficiency of which of the following is most likely to cause it?
Your Answer: Platelets
Explanation:Primary haemostatic control means the first line of defence against immediate bleeding. This is carried out by the platelets. They immediately form a haemostatic plug at the site of injury. Coagulation starts within 20s after an injury to the blood vessel which damage the endothelial cells. Secondary haemostasis follows which includes activation of the coagulation factors to form fibrin strands which mesh together forming the platelet plug. Platelets interact with platelet collagen receptor, glycoprotein Ia/IIa and to collagen fibres in the vascular endothelium. This adhesion is mediated by von Willebrand factor (vWF), which forms links between the platelet glycoprotein Ib/IX/V and collagen fibrils. The platelets are then activated and release the contents of their granules into the plasma, in turn activating other platelets and white blood cells.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 20
Correct
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Laboratory findings in a patient with dark urine and yellowish skin revealed a prolonged prothrombin time. Which of the following is the most likely cause of this finding?
Your Answer: Liver damage
Explanation:Various conditions may prolong the prothrombin time (PT), including: warfarin use, vitamin K deficiency, liver disease, disseminated intravascular coagulopathy, hypofibrinogenemia, heparin infusion, massive blood transfusion and hypothermia. Liver disease causes prolonging of PT due to diminished synthesis of clotting factors. Dark urine colour and jaundice are indicators of the presence of a liver disease in this patient.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 21
Correct
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Leakage from a silicone breast implant can lead to:
Your Answer: Pain and contracture
Explanation:Breast implants are mainly: saline-filled and silicone gel-filled. Complications include haematoma, fluid collections, infection at the surgical site, pain, wrinkling, asymmetric appearance, wound dehiscence and thinning of the breast tissue.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 22
Correct
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A patient is admitted to the ICU, and is prescribed tazobactam, amongst other drugs. What is the mechanism of action of tazobactam?
Your Answer: Inhibits beta-lactamase
Explanation:Tazobactam is a compound which inhibits the action of bacterial beta-lactamases. It is added to the extended-spectrum beta-lactam antibiotic piperacillin to broaden the spectrum of piperacillin by making it effective against organisms that express beta-lactamase and would normally degrade piperacillin.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 23
Correct
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Different portions of the renal tubule have varying degrees of water permeability. Which of the following renal sites is characterised by low water permeability under normal circumstances?
Your Answer: Thick ascending limb of the loop of Henlé
Explanation:Within the nephron of the kidney, the ascending limb of the loop of Henle is a segment of the loop of Henle downstream of the descending limb, after the sharp bend of the loop. Both the thin and the thick ascending limbs of the loop of Henlé have very low permeability to water. Since there are no regulatory mechanisms to alter its permeability, it remains poorly permeable to water under all circumstances. Sodium and chloride are transported out of the luminal fluid into the surrounding interstitial spaces, where they are reabsorbed. Water must remain behind because it is not reabsorbed, so the solute concentration becomes less and less (the luminal fluid becomes more dilute). This is one of the principal mechanisms (along with diminution of ADH secretion) for the production of a dilute, hypo-osmotic urine (water diuresis).
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 24
Incorrect
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The transmembrane proteins responsible for resting membrane potential of vascular smooth muscle cells was blocked by a drug. Which of the following transmembrane proteins were blocked by this drug?
Your Answer: Na+/K+ pump
Correct Answer: K+ channels
Explanation:The resting membrane potential is due to selective permeability of the membrane to potassium ions. The Na/K pump is responsible for the generation of a gradient across the membrane and it is due to the inherent ability of the K channels to allow diffusion back into the nerve at rest which charges the cells. In reality, the resting membrane potential is more positive because of small contributions by Na+ channels, Cl− channels and non-selective cation channels.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 25
Correct
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A 43-year-old diabetic man complains of headaches, palpitations, anxiety, abdominal pain and weakness. He is administered sodium bicarbonate used to treat:
Your Answer: Metabolic acidosis
Explanation:Sodium bicarbonate is indicated in the management of metabolic acidosis, which may occur in severe renal disease, uncontrolled diabetes, circulatory insufficiency due to shock or severe dehydration, extracorporeal circulation of blood, cardiac arrest and severe primary lactic acidosis. Bicarbonate is given at 50-100 mmol at a time under scrupulous monitoring of the arterial blood gas readings. This intervention, however, has some serious complications including lactic acidosis, and in those cases, should be used with great care.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 26
Incorrect
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A 50-year old gentleman who suffered a stroke was brought to the emergency department by his relatives. The patient however denied the presence of paralysis of his left upper and lower limbs. What is the most likely site of the lesion in this patient?
Your Answer: Posterior superior gyrus of left temporal lobe
Correct Answer: Right posterior parietal cortex
Explanation:A large injury to the non-dominant parietal cortex can make the patient neglect or refuse to acknowledge the presence of paralysis on the contralateral side. This can also involve the perception of the external world. Smaller injuries in this area which involve the precentral gyrus (primary motor cortex) or postcentral gyrus (primary sensory cortex) cause contralateral spastic paralysis or contralateral loss of tactile sensation respectively. A lesion in posterior inferior gyrus of the dominant frontal lobe results in motor aphasia. Involvement of the posterior superior gyrus of the dominant frontal lobe produces sensory aphasia.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 27
Correct
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A neurotransmitter of the nigrostriatal pathway is:
Your Answer: Dopamine
Explanation:Dopamine acts as a neurotransmitter in the brain, activating dopamine receptors. It is also a neurohormone released from the hypothalamus. It plays an important role in the reward system. It is believed that dopamine provides a teaching signal to parts of the brain responsible for acquiring new motor sequences (behaviours), by activation of dopamine neurons when an unexpected reward is presented. Loss of dopamine neurones in the nigrostriatal pathway causes Parkinson’s disease. In the frontal lobes, dopamine controls the flow of information from other areas of the brain, and thus, dopamine disorders in this region can cause a decline in neurocognitive functions, especially memory, attention and problem solving. Reduced dopamine concentrations in the prefrontal cortex are thought to contribute to attention-deficit disorder and some symptoms of schizophrenia. Dopamine is also the primary neuroendocrine regulator of the secretion of prolactin from the anterior pituitary gland. Dopamine is also commonly associated with the pleasure system of the brain. This plays a key role in understanding the mechanism of action of drugs (such as cocaine and the amphetamines), which seem to be directly or indirectly related to the increase of dopamine.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 28
Correct
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In a cardiac cycle, what event does the opening of the atrioventricular (AV) valves coincide with?
Your Answer: Beginning of diastole
Explanation:Cardiac diastole refers to the time period when the heart is relaxed after contraction and is preparing to refill with blood. Both ventricular and atrial diastole are together known as complete cardiac diastole. At its beginning, the ventricles relax, causing a drop in the ventricular pressure. As soon as the left ventricular pressure drops below that in left atrium, the mitral valve opens and there is ventricular filling of blood. Similarly, the tricuspid valve opens filling the right atrium.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 29
Correct
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Destruction of the ventromedial nucleus of the hypothalamus will result in:
Your Answer: Loss of satiety
Explanation:The ventromedial nucleus of the hypothalamus is divided into an anterior and a superior part. The anterior part controls the female sexual drive, whereas the superior part is responsible for satiety. Destruction of the superior part of the nucleus will result in overeating, as no signal tells the body that it is satisfied.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 30
Incorrect
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Which of these illnesses is most likely to precede Guillain-Barré syndrome?
Your Answer: Meningitis
Correct Answer: Viral pneumonia
Explanation:Guillain–Barré syndrome (GBS) is characterized by a rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system. In about two-thirds of patients, the syndrome begins 5 days to 3 weeks after an infectious disease, surgery or vaccination. Infection is the trigger in over 50% of patients; common pathogens include Campylobacter jejuni, enteric viruses, herpesviruses (including cytomegalovirus and those causing infectious mononucleosis) and Mycoplasma species. The underlying mechanism involves an autoimmune disorder in which the body’s immune system mistakenly attacks the peripheral nerves and damages their myelin insulation, although the cause for this is still unknown.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
