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Question 1
Incorrect
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Intravenous diazepam was administered to a man who was brought to the emergency department with status epilepticus. He was administered 15 l/min oxygen via a reservoir bag mask. Blood investigations showed sodium = 140 mmol/l, potassium = 4 mmol/l and chloride = 98 mmol/l. His arterial blood gas analysis revealed pH 7.08, p(CO2)= 61.5 mmHg, p(O2) = 111 mmHg and standard bicarbonate = 17 mmol/l. This patient had:
Your Answer: Metabolic acidosis
Correct Answer: Mixed acidosis
Explanation:Acidosis with high p(CO2) and low standard bicarbonate indicates mixed acidosis. Lower p(O2) is due to breathing of 70% oxygen. The prolonged seizures lead to lactic acidosis and the intravenous diazepam is responsible for the respiratory acidosis. Treatment includes airway manoeuvres and oxygen, assisted ventilation if needed, and treatment with fluids.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 2
Incorrect
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In a splenectomy procedure, special care is emphasized on the preservation of the tail of the pancreas that is closely associated with the spleen to avoid post operative pancreatic fistula. As a general surgeon conducting a splenectomy where are you most likely to find the tail of the pancreas in the abdominal cavity?
Your Answer: Hepatoduodenal ligament
Correct Answer: Splenorenal ligament
Explanation:The tail of the pancreas is the only intraperitoneal part of the pancreas and is found contained in the splenorenal ligament of the peritoneal cavity. The splenorenal ligament is derived from the peritoneum where the wall of the general peritoneal cavity connects to the omental bursa between the spleen and the left kidney. This ligament contains the splenic vessels and the tail of the pancreas.
The gastrocolic ligament stretches from the greater curvature of the stomach to the transverse colon, connecting the two.
The gastrosplenic ligament is derived from the greater omentum and is the structure that connects the stomach to the hilum of the spleen. The gastrosplenic ligament continues from the splenic flexure of the colon to the diaphragm and acts as a support to the spleen.
The transverse colon is connected to the abdominal wall by the mesocolon ligament.
The falciform ligament on the other hand, attaches the liver to the ventral wall of the abdomen.
The hepatoduodenal ligament connects the porta hepatis of the liver to the superior part of the duodenum.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 3
Incorrect
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Which of the following is responsible for the activation of pepsinogen released in the stomach?
Your Answer: Glucagon
Correct Answer: Acid pH and pepsin
Explanation:Pepsinogen is the inactive precursor of pepsin. Once secreted, it comes in contact with hydrochloric acid and pepsin, previously formed, and undergoes cleavage to form active pepsin.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 4
Correct
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Blood supply to the posterior compartment of the thigh is supplied by which artery?
Your Answer: Perforating
Explanation:There are usually 3 perforating arteries:
The first gives branches to the adductor brevis and magnus, biceps femoris and gluteus maximus and anastomoses with the inferior gluteal, medial and lateral femoral circumflex.
The second artery supplies the posterior femoral muscles and anastomose with the first and third perforating vessels.
The third supplies the posterior femoral muscles.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 5
Incorrect
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What is the most likely condition a new born infant is likely to suffer from, if he/she was born with incomplete fusion of the embryonic endocardial cushions?
Your Answer: Patent ductus arteriosus
Correct Answer: An atrioventricular septal defect
Explanation:The endocardial cushions in the heart are the mesenchymal tissue that make up the part of the atrioventricular valves, atrial septum and ventricular septum. An incomplete fusion of these mesenchymal cells can cause an atrioventricular septal defect. The terms endocardial cushion defect, atrioventricular septal defect and common atrioventricular canal defect can be used interchangeably with one another.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 6
Correct
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A 45-year-old woman was brought to the emergency department due to fever and chills. She has a history of recurrent UTI and complains of dysuria and urinary frequency. Urinary white blood cell count is >200 cell/high power field. If urine culture is performed, what is the most likely organism that will grow?
Your Answer: Escherichia coli
Explanation:The pathogen that most likely causes recurrent urinary tract infection in young women are E. coli, Enterococcus and Staphylococcus saprophyticus.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 7
Correct
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Which of the following compensatory parameters is responsible for causing an increase in the blood pressure in a 30 year old patient with a BP of 40 mmHg?
Your Answer: Baroreceptor reflex
Explanation:The baroreflex or baroreceptor reflex is one of the body’s homeostatic mechanisms for regulating blood pressure. It provides a negative feedback response in which an elevated blood pressure will causes blood pressure to decrease; similarly, decreased blood pressure depresses the baroreflex, causing blood pressure to rise. The system relies on specialised neurones (baroreceptors) in the aortic arch, carotid sinuses and elsewhere to monitor changes in blood pressure and relay them to the brainstem. Subsequent changes in blood pressure are mediated by the autonomic nervous system. Baroreceptors include those in the auricles of the heart and vena cava, but the most sensitive baroreceptors are in the carotid sinuses and aortic arch. The carotid sinus baroreceptors are innervated by the glossopharyngeal nerve (CN IX); the aortic arch baroreceptors are innervated by the vagus nerve (CN X).
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 8
Incorrect
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Different substances have different renal clearance rates. Which of the following substances should have the lowest renal clearance rate in a healthy patient?
Your Answer: Sodium
Correct Answer: Glucose
Explanation:Under normal conditions the renal clearance of glucose is zero, since glucose is completely reabsorbed in the renal tubules and not excreted. Glycosuria – the excretion of glucose into the urine- is nearly always caused by elevated blood glucose levels, most commonly due to untreated diabetes mellitus.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 9
Incorrect
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A patient in the recovery ward after cardiac surgery is noticed to have a small effusion in the lowest extent of the pleural cavity, into which no lung tissue extends. What is the name of this part of the pleural cavity?
Your Answer: Inferior mediastinum
Correct Answer: Costodiaphragmatic recess
Explanation:The costodiaphragmatic recess is the part of the pleural cavity where the costal pleura is in continuity with the diaphragmatic pleura. It forms the lowest extent of the pleural cavity.
Costomediastinal recess: a tiny recess that is anteriorly located, where the costal pleura becomes continuous with the mediastinal pleura.
The cupola is the pleural cavity that extends above the first rib.
The inferior mediastinum refers to the posterior, middle and anterior mediastinal divisions together.
The pulmonary ligament on the other hand, is a pleural fold that is situated beneath the root of the lung on the medial aspect of the lung.
Oblique pericardial sinus is not part of the pleural cavity.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 10
Correct
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Question 11
Correct
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A 35 year old male patient sustained a traumatic head injury. The patient had loss of consciousness, woke up momentarily when he was in the emergency room but became drowsy and comatose a few hours after. CT scan of the brain showed accumulation of blood between the dura and the cranial bone on the left side of his head. What type of haemorrhage did the patient have?
Your Answer: Epidural
Explanation:Epidural hematoma, also known as epidural bleeding, is a type of traumatic brain injury (TBI) in which a build-up of blood occurs between the dura mater (the tough outer membrane of the central nervous system) and the skull. The spinal cord is also covered by a layer of dura mater, so epidural bleeds may also occur in the spinal column. Often due to trauma, the condition is potentially deadly because the build-up of blood may increase pressure in the intracranial space, compressing delicate brain tissue, and causing brain shift. The condition is present in one to three percent of head injuries. Around 15–20% of epidural hematomas are fatal.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 12
Incorrect
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The gastrosplenic ligament also known as the gastrolienal ligament is the structure that connects the greater curvature of the stomach to the hilum of the spleen. Which of the following arteries would most likely be injured if a surgeon accidentally tore this ligament?
Your Answer: Hepatic artery proper
Correct Answer: Short gastric
Explanation:The short gastric arteries arise from the end of the splenic arteries and form five to seven branches. The short gastric arteries inside the gastrosplenic ligament from the left to the right, supply the greater curvature of the stomach. The hepatic artery proper runs inside the hepatoduodenal ligament. The right gastric artery and the left gastric artery are contained in the hepatogastric ligament. The caudal pancreatic artery branches off from the splenic artery and supplies the tail of the pancreas. The middle colic artery supplies the transverse colon. The splenic artery does not travel in the gastrosplenic ligament and so it would not be damaged by a tear to this ligament.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 13
Correct
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Which muscles are attached to the tibial tuberosity?
Your Answer: Vastus intermedius
Explanation:The tuberosity of the tibia is the site of attachment to the ligamentum patella (the tendon of the quadriceps femoris muscle which include four heads: rectus femoris, vastus medialis, intermedius and lateralis).
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 14
Incorrect
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A 55 year old lady underwent an uneventful appendicectomy. Two hours later, her arterial blood gas analysis on room revealed pH: 7.30, p(CO2): 53 mmHg and p(O2): 79 mmHg. What is the most likely cause of these findings?
Your Answer: Occult haemorrhage
Correct Answer: Alveolar hypoventilation
Explanation:In the given problem, there is respiratory acidosis due to hypercapnia from a low respiratory rate and/or volume (hypoventilation). Causes of hypoventilation include conditions impairing the central nervous system (CNS) respiratory drive, impaired neuromuscular transmission and other causes of muscular weakness (drugs and sedatives), along with obstructive, restrictive and parenchymal pulmonary disorders. Hypoventilation leads to hypoxia and hypercapnia reduces the arterial pH. Severe acidosis leads to pulmonary arteriolar vasoconstriction, systemic vascular dilatation, reduced myocardial contractility, hyperkalaemia, hypotension and cardiac irritability resulting in arrhythmias. Raised carbon dioxide concentration also causes cerebral vasodilatation and raised intracranial pressure. Over time, buffering and renal compensation occurs. However, this might not be seen in acute scenarios where the rise in p(CO2) occurs rapidly.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 15
Correct
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Which of these illnesses is most likely to precede Guillain-Barré syndrome?
Your 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:
- Neurology
- Pathology
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Question 16
Incorrect
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A 45 -year-old female is recently diagnosed with breast cancer. She has a 8-cm-diameter mass in her left breast, with enlarged left axillary node. What is the most likely stage of her disease?
Your Answer: IIIB
Correct Answer: IIIA
Explanation:Stage IIIA breast cancer is T0–2 N2 M0 or T3 N1-2 M0 disease. It describes invasive breast cancer in which either: the tumour is smaller than 5 cm in diameter and has spread to 4 to 9 axillary lymph nodes; or it is found through imaging studies or clinical exam to have spread to internal mammary nodes (near the breastbone found during imaging tests or a physical exam); or the tumour is larger than 5 cm and has spread to 1 to 9 axillary nodes, or to internal mammary nodes. In this stage, the cancer has not metastasized (spread to distant sites).
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 17
Correct
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Which of the following morphological features is most characteristic of hyaline degeneration?
Your Answer: Homogeneous, ground-glass, pink-staining appearance of cells
Explanation:The characteristic morphological features of hyaline degeneration is ground-glass, pinking staining cytoplasm with an intact cell membrane. The accumulation of lipids, calcium salts, lipofuscin and an amorphous cytoplasm with an intact cell membrane are all characteristically found in different situations.
Pyknotic nucleus and orphan Annie eye nucleus are not seen in hyaline degeneration.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 18
Correct
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An explorative laparotomy is done on a 23 year old following a gunshot abdominal injury through the right iliac fossa. It is found that the ileocolic artery is severed and the bullet had perforated the caecum. From which branch does the ileocolic artery originate?
Your Answer: Superior mesenteric artery
Explanation:Ileocolic artery branches off from the superior mesenteric artery. It then divides to give a superior and inferior branch.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 19
Correct
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A teenager presents with pain and swelling in a limb which increases after activity. X-rays reveal an expansible, eccentric, lytic lesion in the metaphysis distally in the affected bone surrounded by new bone. What is the most likely diagnosis?
Your Answer: Aneurysmal bone cyst
Explanation:Aneurysmal bone cysts tend to develop in patients younger than 20 years old. They usually occur in the metaphyseal region of long bones, and are cystic lesions composed of numerous blood filled channels that grow slowly. In X-rays, they show up as circumscribed lesions, sometimes surrounded by new bone.
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This question is part of the following fields:
- Orthopaedics
- Pathology
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Question 20
Incorrect
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Lateral medullary syndrome, also known as Wallenberg's syndrome is a neurological condition caused by ischaemia in the lateral part of the medulla oblongata and is commonly associated with numerous neurological symptoms. Which of the following arteries when occluded leads to this condition?
Your Answer: Anterior spinal
Correct Answer: Posterior inferior cerebellar
Explanation:The lateral medullary syndrome or Wallenberg’s disease is also known as posterior inferior cerebellar artery syndrome (PICA). This syndrome is a clinical manifestation of the occlusion of the posterior cerebellar artery that results in symptoms of infarction of the lateral medullary oblongata. Other arteries that contribute to blood flow in to this region such are the vertebral artery, superior middle cerebellar and inferior medullary arteries can also result to this syndrome when occluded.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 21
Correct
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13 year old girl developed sun burnt cheeks after spending the day playing on the beach. What is the underlying mechanism to her injury?
Your Answer: Free radical injury
Explanation:Free radicals are a by-product of chemical reactions with an unpaired electron in their outer most shell. They are capable of causing wide spread damage to cells. They can cause autolytic reactions thereby converting the reactants into free radicals. By absorbing sun light, the energy is used to hydrolyse water into hydroxyl (OH) and hydrogen (H) free radicals which can cause injury by lipid peroxidation of membranes, oxidative modification of proteins and damage to the DNA structure.
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This question is part of the following fields:
- Cell Injury & Wound Healing; Dermatology
- Pathology
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Question 22
Incorrect
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A 30-year-old woman is diagnosed with Hodgkin's lymphoma. Which of the following chemotherapy regimens would be used in this case?
Your Answer: CHOP
Correct Answer: ABVD
Explanation:ABVD is a chemotherapy regimen used in the first-line treatment of Hodgkin’s lymphoma. It consists of concurrent treatment with the chemotherapy drugs, adriamycin, bleomycin, vinblastine and dacarbazine. It supplanted the older MOPP protocol.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 23
Correct
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A 65-year-old man complains of headaches, weakness, cramps, and confusion; blood tests reveal he has severe hyponatremia. The most likely cause is:
Your Answer: Severe diarrhoea or vomiting
Explanation:Hyponatraemia occurs when the sodium level in the plasma falls below 135 mmol/l. Hyponatraemia is an abnormality that can occur in isolation or, more commonly as a complication of other medical illnesses. Severe hyponatraemia may cause osmotic shift of water from the plasma into the brain cells. Typical symptoms include nausea, vomiting, headache and malaise. As the hyponatraemia worsens, confusion, diminished reflexes, convulsions, stupor or coma may occur. The cause of hyponatremia is typically classified by a person’s fluid status into low volume, normal volume, and high volume. Low volume hyponatremia can occur from diarrhoea, vomiting, diuretics, and sweating.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 24
Correct
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Where does the ejaculatory duct open into?
Your Answer: Prostatic urethra
Explanation:There are two ejaculatory ducts, one on either side of the midline. Each ejaculatory duct is formed by the union of the duct from the seminal vesicles with the ductus deferens. They start at the base of the prostate and run forward and downward between the middle and lateral lobes and along the side of the prostatic utricle to end in the prostatic urethra.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 25
Incorrect
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Perforin are present in the granules of which cell?
Your Answer: Kupffer cell
Correct 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 26
Correct
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The lateral thoracic artery:
Your Answer: Accompanies the long thoracic nerve to the serratus anterior muscle
Explanation:The thoracic nerve, along with the lateral thoracic artery, follow the pectoralis minor to the side of the chest which supplies the serratus anterior and the pectoralis. It then sends branches across the axilla to the axillary glands and subscapularis. The pectoral branch of the thoraco-acromial anastomoses with the internal mammary, subscapular and intercostal arteries, which in women, supply an external mammary branch.
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This question is part of the following fields:
- Anatomy
- Breast
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Question 27
Incorrect
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Injury to this nerve will result to the loss of general sensory innervation of the lacrimal gland:
Your Answer: Optic nerve
Correct Answer: Ophthalmic nerve
Explanation:The lacrimal glands are paired, almond-shaped exocrine glands, that secrete the aqueous layer of the tear film. The lacrimal nerve, derived from the ophthalmic nerve, supplies the sensory component of the lacrimal gland. The greater petrosal nerve, derived from the facial nerve, supplies the parasympathetic autonomic component of the lacrimal gland.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 28
Correct
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During a car accident, the side mirror shattered and a broken piece of glass severed the posterolateral aspect of the driver's neck. A physical examination reveals that the driver is unable to elevate the tip of his shoulder on the side that was injured. Which nerve was injured?
Your Answer: Accessory
Explanation:The tip of the shoulder is formed by the acromion of the scapula. This part is moved by the trapezius muscle which is innervated by the accessory nerve. Damage to this nerve therefore will prevent the patient from lifting the tip of the shoulder.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 29
Correct
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A previously healthy 40-year-old housewife suddenly complains of a headache and loses consciousness. A CT scan reveals subarachnoid haemorrhage. Which of the following is the most probable cause?
Your Answer: Ruptured berry aneurysm
Explanation:Saccular aneurysms, also known as berry aneurysms, appear as a round outpouching and are the most common form of cerebral aneurysm. They are a congenital intracranial defect, and haemorrhage can occur at any age, but is most common between the ages of 40-65 years. A second rupture (rebleeding) sometimes occurs, most often within about 7 days of the first bleed.
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This question is part of the following fields:
- Neurology
- Pathology
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Question 30
Incorrect
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After a car accident, a 30-year-old woman is alert and only has minor, superficial injuries. 2 hours later, she becomes unconscious and a CT scan reveals a convex, lens-shaped haemorrhage over the right parietal region. The most likely diagnosis is:
Your Answer: Subarachnoid haemorrhage
Correct Answer: Epidural haematoma
Explanation:Epidural haematomas are usually caused by arterial bleeding, classically due to damage to the middle meningeal artery by a temporal bone fracture. Symptoms develop within minutes to several hours after the injury and consist of increasing headache, decreased level of consciousness, hemiparesis and pupillary dilation with loss of light reactivity. Around 15–20% of epidural hematomas are fatal.
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This question is part of the following fields:
- Neurology
- Pathology
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Question 31
Incorrect
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A 63-year old lady presents with pain in multiple bones and renal failure. On enquiry, there is history of recurrent pneumonia in the past. What will be the likely finding on her bone marrow biopsy?
Your Answer: Reed–Sternberg cells
Correct Answer: Plasma cells
Explanation:Multiple myeloma is a plasma cell malignancy that produce excessive monoclonal immunoglobulins. The disease presents with bone pains, renal dysfunction, increased calcium, anaemia and recurrent infections. Diagnosis is by demonstrating the presence of M-protein in urine or serum, lytic bone lesions, light chain proteinuria or excessive plasma cells on marrow biopsy.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 32
Incorrect
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Whilst snorkelling, a 30-year old gentleman has the respiratory rate of 10/min, tidal volume of 550 ml and an effective anatomical dead space of 250 ml. What is his alveolar ventilation?
Your Answer: 2500 ml/min
Correct Answer: 3000 ml/min
Explanation:Alveolar ventilation is the amount of air reaching the alveoli per minute. Alveolar ventilation = respiratory rate × (tidal volume – anatomical dead space volume). Thus, alveolar ventilation = 10 × (550 − 250) = 3000 ml/min.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 33
Incorrect
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A medical student is asked to calculate the net pressure difference in a capillary wall, considering: Interstitial fluid hydrostatic pressure = –3 mmHg, Plasma colloid osmotic pressure = 28 mmHg, Capillary hydrostatic pressure = 17 mmHg, Interstitial fluid colloid osmotic pressure = 8 mmHg, and Filtration coefficient = 1. Which is the correct answer?
Your Answer: -3 mmHg
Correct Answer: 0 mmHg
Explanation:The rate of filtration at any point along a capillary depends on a balance of forces sometimes called Starling’s forces after the physiologist who first described their operation in detail. The Starling principle of fluid exchange is key to understanding how plasma fluid (solvent) within the bloodstream (intravascular fluid) moves to the space outside the bloodstream (extravascular space). Fluid movement = k[(pc– pi)–(Πc– Πi)] where k = capillary filtration coefficient, pc = capillary hydrostatic pressure, pi= interstitial hydrostatic pressure, Πc = capillary colloid osmotic pressure, Πi = interstitial colloid osmotic pressure. Therefore: 1 × [capillary hydrostatic pressure (17) – interstitial fluid hydrostatic pressure (–3)] – [plasma colloid osmotic pressure (28) – interstitial fluid colloid osmotic pressure (8)] = 0 mmHg
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 34
Incorrect
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What is the mostly likely cause of prolonged activated partial thromboplastin time (aPPT) ?
Your Answer: Warfarin therapy
Correct Answer: Heparin therapy
Explanation:The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT) is an indicator for measuring the efficacy of both the intrinsic and common coagulation pathway. Prolonged aPTT may indicate: use of heparin, antiphospholipid antibody and coagulation factor deficiency (e.g., haemophilia). Deficiencies of factors VIII, IX, XI and XII and rarely von Willebrand factor (if causing a low factor VIII level) may lead to a prolonged aPTT correcting on mixing studies.
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This question is part of the following fields:
- General
- Physiology
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Question 35
Incorrect
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A young man in a motor vehicle accident sustained a spinal injury at C8 level. What would likely be seen in this patient?
Your Answer: The muscles innervated by the radial nerve that would most likely be affected would be the most proximal ones
Correct Answer: The hypothenar muscles would be completely paralysed
Explanation:The eighth cervical nerve is one of the contributors of the ulnar nerve. The ulnar nerve supplies the hypothenar muscles which include the opponens digiti minimi, abductor digiti minimi, flexor digiti minimi brevis, and palmaris brevis.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 36
Correct
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Which nuclei of the posterior grey column of the spinal cord are likely affected in a patient who has lost the sensation of pain and temperature?
Your Answer: Substantia gelatinosa
Explanation:Substantia gelatinosa is one of the nuclei in the posterior grey column along side other posterior grey column nuclei like the nucleus dorsalis, nucleus proprius, and posteromarginal nucleus. These nuclei are a collection of cells in the posterior grey area found in throughout the spinal cord. The substantia gelatinosa receives direct input from the dorsal nerve roots (sensory), especially from thermoreceptors and nociceptors (receptors for temperature and pain).
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This question is part of the following fields:
- Anatomy
- Neurology
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Question 37
Correct
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Rapid eye movement (REM) sleep is likely to be affected by a lesion in the:
Your Answer: Pons
Explanation:Rapid eye movement (REM) sleep is also known as paradoxical sleep, as the summed activity of the brain’s neurons is quite similar to that during waking hours. Characterised by rapid movements of the eyes, most of the vividly recalled dreams occur during this stage of sleep. The total time of REM sleep for an adult is about 90–120 min per night.
Certain neurones in the brainstem, known as REM sleep-on cells, which are located in the pontine tegmentum, are particularly active during REM sleep and are probably responsible for its occurrence. The eye movements associated with REM are generated by the pontine nucleus with projections to the superior colliculus and are associated with PGO (pons, geniculate, occipital) waves.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 38
Correct
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A 45-year old farmer was referred to the surgical clinic with complaints of pain in his right hypochondrium. Investigations confirmed the diagnosis of hepatocellular carcinoma with malignant ascites. According to you, what is the most likely cause of HCC in this patient?
Your Answer: Aflatoxin
Explanation:Aflatoxins are naturally occurring toxins produced by the Aspergillus fungus (most often, A. flavus and A. parasiticus). These organisms are common and their native habitat is soil, decaying vegetation and grains. They can contaminate the grain before harvest or after storage, more likely in high-humidity (at least 7%) or high temperature environment of after stressful conditions like drought. Aflatoxins are mycotoxins and also carcinogenic. They get metabolized in the liver to an epoxide, aflatoxin M1. High exposure can lead to acute necrosis, cirrhosis or liver carcinoma. These substances can cause haemorrhage, acute liver damage, oedema, and alteration in digestion, absorption and/or metabolism of nutrients. Although humans are susceptible to these toxins like all other animals, they have a high tolerance level and hence, rarely develop acute aflatoxicosis. However, children are particularly susceptible to exposure leading to growth impairment and delayed development. Chronic exposure carries a high risk of hepatic cancer, due to intercalation of its metabolite aflatoxin M1 into the DNA and alkylation of the bases because of its epoxide moiety.
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This question is part of the following fields:
- Gastrointestinal; Hepatobiliary
- Pathology
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Question 39
Incorrect
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Low molecular weight heparin (LMWH) has less side effects than heparin and is used in the prophylaxis and treatment of venous and arterial thrombotic disorders. Which of the following is LMWHs mechanism of action?
Your Answer: Inhibition of antithrombin III
Correct Answer: Inhibition of factor Xa
Explanation:Low molecular weight heparin (LMWH) is a anticoagulant that differs from normal heparin in that it has only short chains of polysaccharide. LMWH inhibits thrombin formation by converting antithrombin from a slow to a rapid inactivator of coagulation factor Xa.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 40
Correct
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The gluteus medius muscle:
Your Answer: Is supplied by the superior gluteal nerve
Explanation:The gluteus medius is situated on the outer surface of the pelvis. It arises from the outer surface of the ilium between the iliac crest and posterior gluteal line above and the anterior gluteal line below. The gluteus medius is supplied by the fourth and fifth lumbar and first sacral nerves through the superior gluteal nerve
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This question is part of the following fields:
- Anatomy
- Lower Limb
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SESSION STATS - PERFORMANCE PER SPECIALTY
