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Question 1
Incorrect
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QT interval in the electrocardiogram of a healthy individual is normally:
Your Answer: 0.10 s
Correct Answer: 0.40 s
Explanation:QT interval extends from beginning of the QRS complex till the end of he T-wave and normally lasts for 0.40 s. It is important in the diagnosis of long-QT and short-QT syndrome. The QT interval varies on the basis of heart rate and may need to be corrected.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 2
Correct
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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: 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 3
Incorrect
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A patient with this type of tumour is advised to follow up regularly for monitoring of tumour size as there is a strong correlation with malignant potential and tumour size. Which of the following is the most likely tumour in this patient?
Your Answer: Prostate adenocarcinoma
Correct Answer: Renal adenocarcinoma
Explanation:The distinction between a benign renal adenoma and renal adenocarcinoma is commonly made on the basis of size. Tumours less than 2 cm in size rarely become malignant as opposed to those greater than 3 cm.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 4
Incorrect
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Which type of contractions are responsible for the propulsion of chyme along the small intestine?
Your Answer: Peristaltic waves
Correct Answer: Segmentation
Explanation:Two major types of intestinal contractions are segmentation and peristalsis:
Segmentation occurs most frequently and primarily involves circular muscle. It is essentially a contraction of 2- or 3-cm long intestinal segments while the muscle on either side of it relaxes. Chyme in the segment is displaced in both directions. As the contracted segment relaxes, the previously relaxed segments on either side may contract. This efficiently mixes the chyme with the digestive secretions and exposes the mucosal absorptive surface to the luminal contents. It also serves a propulsive function and contributes to the movement of chyme.
Peristalsis is a propulsive wave of contraction that is initiated by intestinal distension. It is short lived and travels only a few centimetres before dying out. The combined effects of intestinal peristalsis and segmentation provide for both adequate mixing of the intestinal contents and slow, steady movement of chyme.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 5
Incorrect
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A 40-year old Caucasian male came to the hospital with complaints of fatigue and lethargy. On examination, he was found to have raised blood pressure. Urine examination showed >300 mg/dl proteinuria (4+) and 24-hour urine protein 3.5g. No glucose, blood, nitrites, urobilinogen or casts were present in urine. What is the most likely diagnosis?
Your Answer: Post-streptococcal glomerulonephritis
Correct Answer: Membranous glomerulonephritis
Explanation:Membranous glomerulonephritis or nephropathy, is a renal disorder with insidious course and usually affects people aged 30-50 years. 85% cases are primary (or idiopathic). The other 15% are secondary to autoimmune conditions like SLE, infections like malaria or hepatitis B, drugs like captopril and NSAIDs, or malignancies (particularly lung or colonic carcinoma). This disease is caused due to circulating immune complexes which are said to form by binding of antibodies to antigens in glomerular basement membrane. This antigens could be endogenous or derived from systemic circulation. This immune complex triggers the complement system, resulting in formation of membrane attack complex (MAC) on glomerular epithelial cells. This further results in release of proteases and oxidants which damage the capillaries making them ‘leaky’. Moreover, the epithelial cells also secrete a mediator to reduce nephron synthesis and distribution.
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This question is part of the following fields:
- Pathology
- Renal
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Question 6
Incorrect
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When you rest your elbows on a desk, what bony landmark of the upper limb are you resting on?
Your Answer: Coronoid process of the ulna
Correct Answer: Olecranon process of the ulna
Explanation:At the upper and back part of the ulna, there exists a curved eminence which is the olecranon process. This process lodges in the olecranon fossa of the humerus. It’s posterior surface is subcutaneous and this triangular area is what you rest your elbow upon.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 7
Incorrect
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Gastric acid secretion is stimulated by which of the following?
Your Answer: Cholecystokinin
Correct Answer: Gastrin
Explanation:Gastric acid secretion is stimulated by three factors:
– Acetylcholine, from parasympathetic neurones of the vagus nerve that innervate parietal cells directly
– Gastrin, produced by pyloric G-cells
– Histamine, produced by mast cells.
Gastric acid is inhibited by three factors:
– Somatostatin
– Secretin
– Cholecystokinin
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 8
Incorrect
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A 25-year-old football player suffers severe head trauma during a game. Physical examination reveals a decerebrate posture and bilateral papilledema. A CT scan reveals marked diffuse cerebral oedema. This condition will be most severe in which component of the brain?
Your Answer: Dura
Correct Answer: White matter
Explanation:The greatest amount of salt and water increase with cerebral oedema occurs within the white matter. Any swelling from oedema, haemorrhage or haematoma increases the intracranial pressure (ICP). As the ICP increases, the cerebral perfusion decreases and brain tissue can become ischaemic, even leading to brain death.
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This question is part of the following fields:
- Neurology
- Pathology
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Question 9
Incorrect
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An experiment is carried out to observe engulfment and phagocytosis of microbes. Strep pneumoniae are added to a solution of leukocytes with a substance added to enhance the process of phagocytosis. What is this substance?
Your Answer: Immunoglobulin M
Correct Answer: Complement C3b
Explanation:C3b is cleaved from C3 complement with the help of the enzyme C3- convertase. It binds to the cell surface of the offending substance and opsonizes it. This makes it easy for the phagocytes to detect and eliminate them.
IgM does not act as an opsonin but igG does.
Selectins aid leukocytes to bind to the endothelial surfaces.
C5a is a chemo-attractant and histamine a vasodilator.
NADPH oxidises offending substance after phagocytosis within the macrophage.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 10
Incorrect
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A 26-year-old female patient had the following blood report: RBC count = 4. 0 × 106/μl, haematocrit = 27% and haemoglobin = 11 g/dl, mean corpuscular volume (MCV) = 90 fl, mean corpuscular haemoglobin concentration (MCHC) = 41 g/dl. Further examination of blood sample revealed increased osmotic fragility of the erythrocytes. Which of the following is the most likely cause of this patient’s findings?
Your Answer: Thalassaemia
Correct Answer: Spherocytosis
Explanation:Spherocytes are small rounded RBCs. It is due to an inherited defect of the RBC cytoskeleton membrane tethering proteins. Membrane blebs form that are lost over time and cells become round instead of biconcave. As it is a normochromic anaemia, the MCV is normal. it is diagnosed by osmotic fragility test which reveals increased fragility in a hypotonic solution.
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This question is part of the following fields:
- General
- Physiology
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Question 11
Incorrect
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One of the following structures is contained in the anterior compartment of the lower leg. Which is it?
Your Answer: Superficial peroneal nerve
Correct Answer: Extensor hallucis muscle
Explanation:The lower leg is made up of four fascial compartments separated from one another by septa that contain the muscles of the lower leg. The four compartments are ; anterior, lateral, deep posterior and superficial posterior compartments.
These are the compartments and there contents:
i) Anterior compartment: Tibialis anterior muscle, extensor hallucis longus muscle, extensor digitorum longus muscle, peroneus tertius muscles, deep fibular nerve and anterior tibial blood vessels
ii) Lateral compartment: Fibularis longus muscle, brevis muscles and superficial fibular nerve
iii) Deep posterior compartment: Tibialis posterior m., flexor hallucis longus m., flexor digitorum longus m. ,popliteus m. , tibial nerve, posterior tibial artery and posterior tibial vessels such as the fibular artery.
iv) Superficial posterior compartment: Gastrocnemius m., soleus m., plantaris m., medial sural cutaneous nerve
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 12
Correct
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Which of the following proteins acts as cofactor in the thrombin-induced activation of anticoagulant protein C?
Your Answer: Thrombomodulin
Explanation:Thrombomodulin is a protein cofactor expressed on the surface of endothelial cells. Thrombomodulin binds with thrombin forming a complex which activates protein C, initiating the anticoagulant pathway.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 13
Correct
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A 36-year-old woman suddenly suffers from a generalized seizure. She was previously healthy. An emergency CT scan reveals a mass in the posterior fossa, with distortion of the lateral ventricles. After removing the tumour, the biopsy reveals it contains glial fibrillary acidic protein (GEAP). What's the most likely diagnosis?
Your Answer: Astrocytoma
Explanation:Astrocytomas are primary intracranial tumours derived from astrocyte cells of the brain. They can arise in the cerebral hemispheres, in the posterior fossa, in the optic nerve and, rarely, in the spinal cord. These tumours express glial fibrillary acidic protein (GFAP). In almost half of cases, the first symptom of an astrocytoma is the onset of a focal or generalised seizure. Between 60% and 75% of patients will have recurrent seizures during the course of their illness. Secondary clinical sequelae may be caused by elevated intracranial pressure (ICP) cause by the direct mass effect, increased blood volume, or increased cerebrospinal fluid (CSF) volume. CT will usually show distortion of the third and lateral ventricles, with displacement of the anterior and middle cerebral arteries. Histological diagnosis with tissue biopsy will normally reveal an infiltrative character suggestive of the slow growing nature of the tumour.
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This question is part of the following fields:
- Neurology
- Pathology
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Question 14
Incorrect
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A 45-year old with sarcoidosis has enlarged tracheobronchial lymph nodes. Which nerve is most likely to be irritated in this patient?
Your Answer: Right recurrent laryngeal
Correct Answer: Left recurrent laryngeal
Explanation:Tracheobronchial lymph nodes are located at the bifurcation of the trachea and are in three groups i.e. the right superior, left superior and inferior. The aorta arches over the left bronchus near the point of tracheal bifurcation. Thus, the nerves that are closely associated with the aorta might be irritated if these nodes become inflamed. The left recurrent laryngeal nerve is such a nerve. The phrenic nerves, both the left and the right, are lateral and thus would not be affected. The right recurrent nerve loops around the right subclavian artery and is distant from this area. The right vagus artery is not associated with the aorta and the sympathetic chain is located in the posterior chest parallel to the vertebra, also not associated with the tracheobronchial tree.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 15
Incorrect
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From which fascia of the pelvic wall muscle does the levator ani muscle arise?
Your Answer: Psoas major
Correct Answer: Obturator internus
Explanation:The levator ani muscle arises from the posterior surface of the superior ramus of the pubis lateral to the symphysis, behind the inner surface of the spine of the ischium and between these points from the obturator internus fascia. It is attached to the inner surface of the side of the lesser pelvic cavity, supports the viscera in the cavity and surrounds the various structures that pass through it.
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This question is part of the following fields:
- Anatomy
- Pelvis
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Question 16
Correct
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A patient in the intensive care unit developed hyperphosphatemia. The phosphate level is 160 mmol/L. Which of the following is most likely responsible for this abnormality?
Your Answer: Renal insufficiency
Explanation:Hyperphosphatemia is an electrolyte disturbance in which there is an abnormally elevated level of phosphate in the blood. It is caused by conditions that impair renal phosphate excretion (ex: renal insufficiency, hypoparathyroidism, parathyroid suppression) and conditions with massive extracellular fluid phosphate loads (ex: rapid administration of exogenous phosphate, extensive cellular injury or necrosis, transcellular phosphate shifts).
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 17
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
- Pelvis
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Question 18
Correct
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Which of the following is the most abundant WBC seen in a smear from a healthy person.
Your Answer: Neutrophils
Explanation:neutrophils are the most abundant cell type of the WBC. These phagocytes are found normally in the blood and increase in number are seen during an acute inflammation. These the percentages of WBC in blood Neutrophils: 40 to 60%
Lymphocytes: 20 to 40%
Monocytes: 2 to 8%
Eosinophils: 1 to 4%
Basophils: 0.5 to 1%
Band (young neutrophil): 0 to 3%. eosinophils, basophils, neutrophils are known as granulocytes and monocytes and lymphocytes as agranulocytes.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 19
Correct
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A 56-year old male with history of previous abdominal surgery presents to the emergency department with severe abdominal pain that is increasing in intensity. This pain is associated with abdominal distension and faint, high-pitched bowel sounds. An old scar is also noted on the abdomen. An erect abdominal X-ray shows multiple air-fluid levels in dilated bowel loops. No occult blood was found in stool sample. What is the most likely predisposing factor for his present condition?
Your Answer: Adhesions from previous surgery
Explanation:The described features suggest acute bowel obstruction. The scar described points toward previous surgery, which suggests development of peritoneal adhesions that could lead to obstruction. Hepatitis does not lead to dilated bowel loops. Amoebiasis could lead to inflammatory bowel disease, however, occult blood in stool is usually positive. Ileal adenocarcinoma is rare. Meckel’s diverticulum can possibly lea to obstruction but the findings described here are more consistent with obstruction due to peritoneal adhesions from a past surgery.
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This question is part of the following fields:
- Gastrointestinal; Hepatobiliary
- Pathology
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Question 20
Correct
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The uterine artery arises from the?
Your Answer: Internal iliac artery
Explanation:The uterine artery arises from the anterior division of the internal iliac artery and runs medially on the levator ani towards the uterine cervix.
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This question is part of the following fields:
- Anatomy
- Pelvis
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