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Question 1
Correct
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What percentage of the cardiac output is delivered to the brain?
Your Answer: 15%
Explanation:Among all body organs, the brain is most susceptible to ischaemia. Comprising of only 2.5% of total body weight, the brain receives 15% of the cardiac output. Oxygen extraction is also higher with venous oxygen levels approximating 13 vol%, and arteriovenous oxygen difference of 7 vol%.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 2
Incorrect
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A 34-year-old man is receiving chemotherapy for non-Hodgkin's lymphoma. Which of the following chemotherapy regimens would be used in this case?
Your Answer: FOLFOX
Correct Answer: CHOP
Explanation:CHOP is the acronym for a chemotherapy regimen used in the treatment of non-Hodgkin’s lymphoma, comprising cyclophosphamide, hydroxyrubicin (adriamycin), vincristine and prednisone. This regimen can also be combined with the monoclonal antibody rituximab if the lymphoma is of B cell origin; this combination is called R-CHOP.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 3
Correct
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Perforin are present in the granules of which cell?
Your Answer: Natural killer cell
Explanation:Perforins are characteristically found In the granules of CD8+ T cells and natural killer cells. They are cytolytic proteins that insert into the target plasma membrane forming a hole and resulting in lysis. They along with granzyme B induce apoptosis in the target cell.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 4
Correct
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Diuretics that act on the ascending limb of the loop of Henle produce:
Your Answer: Reduced active transport of sodium
Explanation:The loop of Henlé leads from the proximal convoluted tubule to the distal convoluted tubule. Its primary function uses a counter current multiplier mechanism in the medulla to reabsorb water and ions from the urine. It can be divided into four parts:
1. Descending limb of loop of Henlé – low permeability to ions and urea, while being highly permeable to water
2. Thin ascending limb of loop of Henlé – not permeable to water, but it is permeable to ions
3. Medullary thick ascending limb of loop of Henlé – sodium (Na+), potassium (K+) and chloride (Cl–) ions are reabsorbed by active transport. K+ is passively transported along its concentration gradient through a K+ channel in the basolateral aspect of the cells, back into the lumen of the ascending limb.
4. The cortical thick ascending limb – the site of action where loop diuretics such as furosemide block the K+/Na+/2Cl− co-transporters = reduced active transport.
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This question is part of the following fields:
- Physiology
- Renal
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Question 5
Correct
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A 55-year-old man underwent CT scan of the whole abdomen. The result showed renal cell carcinoma with a tumour size of 7cm and extension into the regional lymph. What is the clinical stage of his renal cell cancer?
Your Answer: Stage III
Explanation:Renal cell carcinoma is a kidney cancer that originates in the lining of the proximal convoluted tubule. It is the most common type of kidney cancer in adults, responsible for approximately 90–95% of cases. Renal cell carcinomas can be staged by using the American Joint Committee on Cancer (AJCC) TNM (tumour-node-metastasis) classification, as follows: Stage I: tumours that are 7 cm or smaller and confined to the kidney, Stage II: tumours that are larger than 7 cm but still confined to the kidney, Stage III: tumours extending into the renal vein or vena cava, involving the ipsilateral adrenal gland and/or perinephric fat, or which have spread to one local lymph node and Stage IV: tumours extending beyond Gerota’s fascia, to more than one local node, or with distant metastases Recent literature has questioned whether the cut-off in size between stage I and stage II tumours should be 5 cm instead of 7 cm. The patient’s cancer in this case is stage III.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 6
Incorrect
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An anatomy instructor is giving a demonstration of the right lung. Which of the statements about the right lung made by the demonstrator is correct?
Your Answer: Its upper lobar bronchus lies behind and below the right pulmonary artery
Correct Answer: Its upper lobar bronchus lies behind and above the right pulmonary artery
Explanation:The root of the lungs on both sides are similar in that the pulmonary veins are anterior and inferior while the bronchus is posterior. However, on the right side, the pulmonary arteries are anterior to the bronchus while on the left side the pulmonary arteries are superior to the bronchus. The lingual is only found on the left lung. The mediastinum is the space in the thorax between the two pleural sacs and does not contain any lung. The right lung, having three lobes, is slightly larger than the left lung. On both sides, the phrenic nerves passes in front of the root of the lung.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 7
Correct
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A 78-year-old man who has been bedridden for a month is prescribed griseofulvin. What class of drugs does griseofulvin belong to?
Your Answer: Antifungal
Explanation:Griseofulvin is an antifungal drug. It is administered orally, and it is used to treat ringworm infections of the skin and nails. It binds to keratin in keratin precursor cells and makes them resistant to fungal infections. Griseofulvin works by interfering with fungal mitosis.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 8
Correct
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A 15-day old male baby was brought to the emergency department with sweating and his lips turning blue while feeding. He was born full term. On examination, his temperature was 37.9°C, blood pressure 75/45 mmHg, pulse was 175/min, and respiratory rate was 42/min. A harsh systolic ejection murmur could be heard at the left upper sternal border. X-ray chest showed small, boot-shaped heart with decreased pulmonary vascular markings. He most likely has:
Your Answer: Tetralogy of Fallot
Explanation:The most common congenital cyanotic heart disease and the most common cause of blue baby syndrome, Tetralogy of Fallot shows four cardiac malformations occurring together. These are ventricular septal defect (VSD), pulmonary stenosis (right ventricular outflow obstruction), overriding aorta (degree of which is variable), and right ventricular hypertrophy. The primary determinant of severity of disease is the degree of pulmonary stenosis. Tetralogy of Fallot is seen in 3-6 per 10,000 births and is responsible for 5-7% congenital heart defects, with slightly higher incidence in males. It has also been associated with chromosome 22 deletions and DiGeorge syndrome. It gives rise to right-to-left shunt leading to poor oxygenation of blood. Primary symptom is low oxygen saturation in the blood with or without cyanosis at birth of within first year of life. Affected children ay develop acute severe cyanosis or ‘tet spells’ (sudden, marked increase in cyanosis, with syncope, and may result in hypoxic brain injury and death). Other symptoms include heart murmur, failure to gain weight, poor development, clubbing, dyspnoea on exertion and polycythaemia. Chest X-ray reveals characteristic coeur-en-sabot (boot-shaped) appearance of the heart. Treatment consists of immediate care for cyanotic spells and Blalock–Taussig shunt (BT shunt) followed by corrective surgery.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 9
Incorrect
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Which of the cranial nerves is responsible for touch sensation on the skin over the maxilla region and the mandible?
Your Answer: Glossopharyngeal
Correct Answer: Trigeminal
Explanation:The sensation of the face is provided by the trigeminal nerve which is cranial nerve V. It is also responsible for other motor functions such as biting and chewing. The trigeminal nerve has three branches; the ophthalmic nerve (V1), the maxillary nerve((V2) and the mandibular nerve (V3). These three branches exit the skull through separate foramina, namely; the superior orbital fissure, the foramen rotundum and the foramen ovale respectively. The mnemonic for this is ‘Standing room only’. The sensory fibres of the maxillary nerve are distributed to the lower eyelid and cheek, the nares and upper lip, the upper teeth and gums, the nasal mucosa, the palate and roof of the pharynx, the maxillary, ethmoid and sphenoid sinuses, and parts of the meninges. The sensory fibres of the mandibular nerve are distributed to the lower lip, the lower teeth and gums, the floor of the mouth, the anterior two-thirds of the tongue, the chin and jaw (except the angle of the jaw, which is supplied by C2–C3), parts of the external ear, and parts of the meninges. The mandibular nerve carries touch/ position and pain/temperature sensation from the mouth. The sensory fibres of the ophthalmic nerve are distributed to the scalp and forehead, the upper eyelid, the conjunctiva and cornea of the eye, the nose (including the tip of the nose), the nasal mucosa, the frontal sinuses and parts of the meninges (the dura and blood vessels). The sensory fibres of the maxillary nerve are distributed to the lower eyelid and cheek, the nares and upper lip, the upper teeth and gums, the nasal mucosa, the palate and roof of the pharynx, the maxillary, ethmoid and sphenoid sinuses, and parts of the meninges.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 10
Incorrect
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Which of the following is a true statement regarding secretion of gastric acid?
Your Answer: Somatostatin increases gastric acid secretion
Correct Answer: Acetylcholine increases gastric acid secretion
Explanation:Gastric acid secretion is increased by acetylcholine, histamine and gastrin, with the help of cAMP as a secondary messenger. They increase H+ and Cl- secretion by increasing the number of H+/K+ ATPase molecules and Cl- channels. In contrast, gastric acid secretion is decreased by somatostatin, epidermal growth factor and prostaglandins.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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