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Question 1
Correct
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Ventricular filling follows a delay caused by?
Your Answer: AV node
Explanation:The AV node is a conducting tissue found between the atria and the ventricles of the heart. It conducts electrical signal from the atria to the ventricles and acts a delaying mechanism preventing the atria and the ventricles from contracting at the same time. This decremental conduction prevents premature ventricular contraction in cases such as atrial fibrillation. A delay in the AV node is the reason for the PR segment seen on the ECG. In certain types of supraventricular tachycardia, a person could have two AV nodes; this will cause a loop in electrical current and uncontrollably rapid heart beat. When this electricity catches up with itself, it will dissipate and return to a normal heart rate.
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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 following structures carry part of the right bundle branch of the AV bundle?
Your Answer: Moderator band (septomarginal trabecula)
Explanation:The moderator band extends from the base of the anterior papillary muscle to the ventricular septum. It is the structure which carries part of the right AV bundle. Its role it to prevent overdistention of the ventricle.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 3
Correct
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After a prolonged coronary artery bypass surgery, a 60-year old gentleman was transfused 3 units of fresh-frozen plasma and 2 units of packed red cells. Two days later, the nurse noticed that he was tachypnoeic and chest X-ray showed signs consistent with adult respiratory distress syndrome. Which of the following variables will be low in this patient?
Your Answer: Compliance of the lung
Explanation:Acute or adult respiratory distress syndrome (ARDS) is a reaction to several forms of lung injuries and is commonly associated with sepsis and SIRS (systemic inflammatory response syndrome), severe traumatic injury, severe head injury, narcotics overdose, drowning, pulmonary contusion, and multiple blood transfusions. There is an increase in risk due to pre-existing liver disease or coagulation abnormalities. It results due to indirect toxic effects of neutrophil-derived inflammatory mediators in the lungs. ARDS is defined by the 1994 American–European Consensus Committee as the acute onset of bilateral infiltrates on chest X-ray, a partial pressure of arterial oxygen (pa(O2)) to fraction of inspired oxygen Fi(O2) ratio of less than 200 mmHg and a pulmonary artery occlusion pressure of less than 18 or the absence of clinical evidence of left arterial hypertension. ARDS is basically pulmonary oedema in the absence of volume overload or poor left ventricular function. This is different from acute lung injury, which shows a pa(O2)/Fi(O2) ratio of less than 300 mmHg. Pathogenesis of ARDS starts from damage to alveolar epithelium and vascular endothelium, causing increased permeability. Damage to surfactant-producing type II cells disrupts the production and function of pulmonary surfactant, causing micro atelectasis and poor gas exchange. There is a decrease in lung compliance and increase in work of breathing. Eventually, there is resorption of alveolar oedema, regeneration of epithelial cells, proliferation and differentiation of type II alveolar cells and alveolar remodelling. Some show resolution and some progress to fibrosing alveolitis, which involves the deposition of collagen in alveolar, vascular and interstitial spaces.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 4
Correct
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A histology report of a cervical biopsy taken from a patient with tuberculosis revealed the presence of epithelioid cells. What are these cells formed from?
Your Answer: Macrophages
Explanation:Granulomas formed in tuberculosis are called tubercles and are made up polynuclear phagocytes, Langhans cells and epithelioid cells. Macrophages when enlarged, consist of abundant cytoplasm and have a tendency of arranging themselves very closely to each other representing epithelial cells. These enlarged macrophages are therefore termed as epithelioid cells.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 5
Correct
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A 24 year old mother is breastfeeding her first child. Which of the following cellular adaptations occurred in her breast tissue to allow her to do this?
Your Answer: Lobular hyperplasia
Explanation:Under the influence of oestrogen in pregnancy, there is an increase in the number of lobules which will facilitate lactation.
Steatocytes occur due to loss of weight and nutritional deficit.
Metaplasia is a normal physiological process which is due to a change in normal epithelium with another type.
Lobular atrophy will result in a decreased capacity to provide milk.
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This question is part of the following fields:
- Cell Injury & Wound Healing; Female Health
- Pathology
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Question 6
Correct
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A 50-year-old woman goes to the doctor complaining of myalgia, muscle cramps, and weakness; she is diagnosed with severe hypokalaemia. Which of the following is the most common cause of hypokalaemia?
Your Answer: Prolonged vomiting
Explanation:Potassium is one of the body’s major ions. Nearly 98% of the body’s potassium is intracellular. The ratio of intracellular to extracellular potassium is important in determining the cellular membrane potential. Small changes in the extracellular potassium level can have profound effects on the function of the cardiovascular and neuromuscular systems. Hypokalaemia may result from conditions as varied as renal or gastrointestinal (GI) losses, inadequate diet, transcellular shift (movement of potassium from serum into cells) and medications. The important causes of hypokalaemia are:
Renal losses: renal tubular acidosis, hyperaldosteronism, magnesium depletion, leukaemia (mechanism uncertain).
GI losses: vomiting or nasogastric suctioning, diarrhoea, enemas or laxative use, ileal loop.
Medication effects: diuretics (most common cause), β-adrenergic agonists, steroids, theophylline, aminoglycosides.
Transcellular shift: insulin, alkalosis.
Severe hypokalaemia, with serum potassium concentrations of 2.5–3 meq/l, may cause muscle weakness, myalgia, tremor, muscle cramps and constipation.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 7
Correct
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During a surgical operation, whilst dissecting the mediastinal lymph nodes for a bronchogenic carcinoma of the right upper lobe bronchus, a patient's right sympathetic trunk is accidentally severed above the level of spinal nerve T1. Which function would be left intact in the affected region?
Your Answer: Voluntary muscle activity
Explanation:The sympathetic nervous system regulates vascular tone, dilation of pupils, arrector pili muscles, sweat production and visceral reflexes. Neurones that supply the voluntary muscles originate from the ventral horn of the spinal cord. If these nerves were thus damaged, these functions would be impaired. The sympathetic nervous system is not responsible for voluntary muscle activity.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 8
Correct
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Where do the cells belonging to the mononuclear phagocyte system originate?
Your Answer: Bone marrow
Explanation:The macrophage originates from a committed bone marrow stem cell. It is called the pluripotent hematopoietic stem cell. This differentiates into a monoblast and then into a promonocyte and finally matures into a monocyte. When called upon they leave the bone marrow and enter into the circulation. Upon entering the tissue they transform into macrophages. Tissue macrophages include: Kupffer cells (liver), alveolar macrophages (lung), osteoclasts (bone), Langerhans cells (skin), microglial cells (central nervous system), and possibly the dendritic immunocytes of the dermis, spleen and lymph nodes.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 9
Correct
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Anthrax is an infection caused by the bacterium Bacillus anthracis. Anthrax spores have been used as a biological warfare weapon. What is the drug of choice in treating anthrax infection?
Your Answer: Ciprofloxacin
Explanation:Early antibiotic treatment of anthrax is essential. A delay may significantly lessen the chances for survival of the patient. Treatment for anthrax infection include large doses of intravenous and oral antibiotics, such as fluoroquinolones (ciprofloxacin), doxycycline, erythromycin, vancomycin, or penicillin.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 10
Correct
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Difficulty in retracting the foreskin of the penis in an uncircumcised male is known as:
Your Answer: Phimosis
Explanation:Phimosis is the inability to fully retract the foreskin of the penis in an uncircumcised male. It can be physiological in infancy, in which it could be referred to as ‘developmental non-retractility of the foreskin. However, it is almost always pathological in older children and men. Causes include chronic inflammation (e.g. balanoposthitis), multiple catheterisations, or forceful foreskin retraction. One of the causes is chronic balanitis xerotica obliterans. It leads to development of a ring of indurated tissue near the tip of the prepuce, which prevents retraction. Contributory factors include infections, hormonal and inflammatory factors. The recommended treatment includes circumcision.
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This question is part of the following fields:
- Pathology
- Urology
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Question 11
Correct
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The periphery of a haematoma is infiltrated by fibroblasts, collagen and new vasculature. This process is best described as?
Your Answer: Organisation of the haematoma
Explanation:Formation of granulation tissue at the periphery of the hematoma is a normal process leading to resolution. This granulation tissue is composed of new capillaries, fibroblasts and collagen. Lysis of a blood clot can occur, but the actual process of this response is known as organization, wherein the scar tissue will become part of the vessels. This is followed by recanalization and embolization which can lead to eventual complications. Proliferation of a clot will occur due to an imbalance in the clotting and lysing systems. Thrombosis has nothing to do with the process described above.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 12
Correct
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An old man fell and fractured a carpal bone articulating with the pisiform bone. Which bone was most likely fractured?
Your Answer: Triquetral
Explanation:The pisiform bone has an oval facet for articulation with the triquetral bone. The pisiform bone is a sesamoid bone, and is anterior to the other carpal bones.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 13
Correct
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A 5-year-old child diagnosed with nephrotic syndrome developed generalised oedema. What is the mechanism for the development of oedema in patients with nephrotic syndrome?
Your Answer: Decreased colloid osmotic pressure
Explanation:The development of oedema in nephrotic syndrome has traditionally been viewed as an underfill mechanism. According to this view, urinary loss of protein results in hypoalbuminemia and decreased plasma oncotic pressure. As a result, plasma water translocates out of the intravascular space and results in a decrease in intravascular volume. In response to the underfilled circulation, effector mechanisms are then activated that signal the kidney to secondarily retain salt and water. While an underfill mechanism may be responsible for oedema formation in a minority of patients, recent clinical and experimental findings would suggest that oedema formation in most nephrotic patients is the result of primary salt retention. Direct measurements of blood and plasma volume or measurement of neurohumoral markers that indirectly reflect effective circulatory volume are mostly consistent with either euvolemia or a volume expanded state. The ability to maintain plasma volume in the setting of a decreased plasma oncotic pressure is achieved by alterations in transcapillary exchange mechanisms known to occur in the setting of hypoalbuminemia that limit excessive capillary fluid filtration.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 14
Correct
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What Is the mechanism behind rhesus incompatibility in a new born baby?
Your Answer: Type II hypersensitivity
Explanation:In type II hypersensitivity the antibodies that are produced by the immune response bind to the patients own cell surface antigens. These antigens can be intrinsic or extrinsic. Destruction occurs due to antibody dependent cell mediated antibodies. Antibodies bind to the cell and opsonise the cell, activating phagocytes to destroy that cell e.g. autoimmune haemolytic anaemia, Goodpasture syndrome, erythroblastosis fetalis, pernicious anaemia, Graves’ disease, Myasthenia gravis and haemolytic disease of the new-born.
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This question is part of the following fields:
- Inflammation & Immunology; Haematology
- Pathology
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Question 15
Correct
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Regarding innervation to the peroneus brevis muscle:
Your Answer: Could be damaged by a fracture of the neck of the fibula
Explanation:The peroneus brevis is supplied by the fourth and fifth lumbar and first sacral nerves through the superficial peroneal nerve which is one of the two terminal branches of the common peroneal nerve. The common peroneal nerve winds around the neck of the fibula and can be injured in cases of fractured neck of fibula.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 16
Correct
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A 6 year-old boy is brought to you coughing. He is suspected to have aspirated a Lego piece which he was seen playing with. Where would you expect the piece to be?
Your Answer: Right main bronchus
Explanation:Inhaled objects are more likely to enter the right lung for several reasons. First the right bronchus is shorter, wider and more vertical than the left bronchus. Also, the carina (a ridge-like structure at the point of tracheal bifurcation) is set a little towards the left. The terminal bronchiole is a very small space and impossible for the seed to lodge here.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 17
Correct
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Which of the following structures is derived from the dorsal mesogastrium of the stomach during the development of the gut?
Your Answer: Greater omentum
Explanation:In a developing foetus, the stomach has two mesogastria from which most of the abdominal ligaments develop. These two mesogastria are the; ventral mesogastrium and the dorsal mesogastrium. During the embryological development of the gut, different organs develop in each mesogastrium; the spleen and pancreas in the dorsal mesogastrium while the liver in the ventral mesogastrium (with their associated ligaments). In the dorsal mesogastrium the following structures develop; the greater omentum (containing the gastrophrenic ligament and the gastrocolic ligament), gastrosplenic ligament, mesentery, splenorenal ligament and phrenicocolic ligament. The structures that develop from the ventral mesogastrium include the; lesser omentum (containing the hepatoduodenal ligament and the hepatogastric ligament) in association with the liver; the coronary ligament (left triangular ligament, right triangular ligament and hepatorenal ligament) and the falciform ligament (round ligament of liver and ligamentum venosum within).
There are also folds that develop from the dorsal mesogastrium which include; umbilical folds, supravesical fossa, medial inguinal fossa, lateral umbilical fold, lateral inguinal fossa and Ileocecal fold.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 18
Incorrect
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A 60-year old patient presenting with squamous cell carcinoma of the anal canal was brought in to the oncology ward for chemotherapy. In which of the following lymph nodes of this patient would you likely find metastases?
Your Answer: Superficial inguinal
Correct Answer: Internal iliac
Explanation:The efferent lymphatics from the anal canal proceed to the internal iliac lymph nodes. This would most likely form the site of enlargement in the lymphatics.
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This question is part of the following fields:
- Anatomy
- Pelvis
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Question 19
Correct
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Which of the following will be affected by a lesion in the posterior column-medial lemniscus system?
Your Answer: Fine touch
Explanation:The posterior column–medial lemniscus (PCML) pathway is a sensory pathway that transmits fine touch and conscious proprioceptive information from the body to the brain. As the posterior columns are also known as dorsal columns, the pathway is also called the dorsal column–medial lemniscus system or DCML.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 20
Correct
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The blood investigations of a 30-year old man with jaundice revealed the following : total bilirubin 6.5 mg/dl, direct bilirubin 1.1 mg/dl, indirect bilirubin 5.4 mg/dl and haemoglobin 7.3 mg/dl. What is the most likely diagnosis out of the following?
Your Answer: Haemolysis
Explanation:Hyperbilirubinemia can be caused due to increased bilirubin production, decreased liver uptake or conjugation, or decreased biliary excretion. Normal bilirubin level is less than 1.2 mg/dl (<20 μmol/l), with most of it unconjugated. Elevated unconjugated bilirubin (indirect bilirubin fraction >85%) can occur due to haemolysis (increased bilirubin production) or defective liver uptake/conjugation (Gilbert syndrome). Such increases are less than five-fold usually (<6 mg/dl or <100 μmol/l) unless there is coexistent liver disease.
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This question is part of the following fields:
- Gastrointestinal; Hepatobiliary
- Pathology
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Question 21
Correct
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An episiotomy is indicated for a woman during a difficult vaginal delivery. Whilst the registrar was performing this procedure she made a median cut too far through the perineal body cutting the structure immediately posterior. Which structure is this?
Your Answer: External anal sphincter
Explanation:An episiotomy is an incision that is made whenever there is a risk of a tear during vaginal deliver. A posterolateral incision, as opposed to a median incision is preferred. Of the options given, the external anal sphincter lies right posterior to the perineal body. The sacrospinous and the sacrotuberous ligaments are deep in the perineum that they should not be involved in this.
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This question is part of the following fields:
- Anatomy
- Pelvis
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Question 22
Correct
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If the blood flow is constant, oxygen extraction by tissues will show the greatest decrease due to which of the following interventions?
Your Answer: Tissue cooling
Explanation:With a constant blood flow to a given tissue bed, there will be an increase in oxygen extraction by the tissue with the following; an increase in tissue metabolism and oxygen requirements: warming (or fever), exercise, catecholamines and thyroxine. With cooling, the demand for oxygen decreases, leading to decreased oxygen extraction.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 23
Correct
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What is expected from complete transection of the inferior gluteal nerve when it emerges from the greater sciatic foramen?
Your Answer: Extension of the thigh would be the action most affected
Explanation:As the inferior gluteal nerve emerges from the greater sciatic foramen below the piriformis muscle, it divides into branches and enters the gluteus maximus muscle which extends the femur and bends the thigh in line with the body.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 24
Correct
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A 14-year old girl presented with a 2cm, mobile, cystic mass in the midline of her neck. Fine needle aspiration of the mass revealed clear fluid. This is most likely a case of:
Your Answer: Thyroglossal duct cyst
Explanation:Thyroglossal cyst is the most common congenital thyroid anomaly which is clinically significant and affects women more than men. It is a vestigial remnant of developing thyroid. Although the thyroglossal cyst can develop anywhere along the thyroglossal duct, the most common site is in the midline between the isthmus of thyroid and hyoid bone, or just above the hyoid. Thyroglossal cysts are also associated with ectopic thyroid tissue. Clinically, the cyst moves upward with protrusion of the tongue. Rarely, the persistent duct can become malignant (thyroglossal duct carcinoma) where the cancerous cells arise in the ectopic thyroid tissue that are deposited along the duct. Exposure to radiation is a predisposing factor.
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This question is part of the following fields:
- Endocrine
- Pathology
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Question 25
Correct
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If a 70-year-old man with known atrial fibrillation dies suddenly, which of these is the most likely cause of death?
Your Answer: Thromboembolism
Explanation:In atrial fibrillation, the abnormal atrial contraction can cause blood to stagnate in the left atrium and form a thrombus, which may then embolize. The patient’s history of AF suggest an embolic disease, which lead to his death.
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This question is part of the following fields:
- Cardiovascular
- Pathology
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Question 26
Correct
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Which of the following conditions causes an elevation of the pH in the tissues with elevated arterial CO2 content?
Your Answer: Metabolic alkalosis
Explanation:Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35-7.45). This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct result of increased bicarbonate concentrations. Normally, arterial pa(CO2) increases by 0.5–0.7 mmHg for every 1 mEq/l increase in plasma bicarbonate concentration, a compensatory response that is very quick. If the change in pa(CO2) is not within this range, then a mixed acid–base disturbance occurs.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 27
Correct
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A child presents with hypertension. Serum potassium analysis shows hypokalaemia. What is the most likely diagnosis?
Your Answer: Liddle syndrome
Explanation:Liddle’s syndrome,  is an autosomal dominant disorder, that is characterized by early, and frequently severe, high blood pressure associated with low plasma renin activity, metabolic alkalosis, low blood potassium, and normal to low levels of aldosterone. Liddle syndrome involves abnormal kidney function, with excess reabsorption of sodium and loss of potassium from the renal tubule. Bartter Syndrome also presents with hypokalaemia, however blood pressure of these patients is usually low or normal.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 28
Correct
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A surgeon performing a laparoscopic repair of an inguinal hernia visualizes a loop of bowel protruding through the abdominal wall to form a direct inguinal hernia. When this is viewed from the side of the abdomen with a laparoscope, in which region would the hernial sac be?
Your Answer: Medial inguinal fossa
Explanation:In a direct inguinal hernia, visceral contents exit the abdomen through a weak point in the fascia in the medial inguinal fossa i.e. the area between the medial and lateral umbilical folds. Such a hernia doesn’t pass through the deep inguinal ring or the lateral inguinal fossa. Note that direct hernias can go through the superficial inguinal ring, although rarely. The supravesical fossa, between the median and medial umbilical folds, is formed by a peritoneal reflection from the anterior abdominal wall onto the bladder and the retrovesical fossa is the region behind the urinary bladder.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 29
Correct
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The most important difference between interstitial fluid and plasma is the:
Your Answer: Protein concentration
Explanation:Interstitial fluid (or tissue fluid or intercellular fluid) is a solution that surrounds the cells of multicellular animals. It is the main component of the extracellular fluid, which also includes plasma, lymph and transcellular fluid. Plasma, the major component in blood, communicates freely with interstitial fluid through pores and intercellular clefts in capillary endothelium. Interstitial fluid consists of a water solvent containing amino acids, sugars, fatty acids, coenzymes, hormones, neurotransmitters, salts, as well as waste products from the cells. Red blood cells, platelets and plasma proteins cannot pass through the walls of the capillaries. The resulting mixture that does pass through is essentially blood plasma without the plasma proteins. Tissue fluid also contains certain types of white blood cells. Once the extracellular fluid collects into small vessels it is considered to be lymph, and the vessels that carry it back to the blood are called the lymphatic vessels. The lymphatic system returns protein and excess interstitial fluid to the circulation.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 30
Correct
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A CT-scan report of a patient with gastric carcinoma shows that the lymph nodes around the coeliac trunk are enlarged. The coeliac trunk:
Your Answer: Gives rise to the splenic, left gastric and common hepatic arteries
Explanation:The coeliac trunk is a branch of the aorta arising just below the aortic hiatus of the diaphragm to pass nearly horizontally forward to divide into 3 large branches i.e. the left gastric, the hepatic and the splenic arteries. Occasionally it may give off one of the inferior phrenic arteries. It is covered by the lesser omentum and on the right side bordered by the right coeliac ganglion and the cardiac end of the stomach. Inferiorly it is bordered by the upper border of the pancreas and splenic vein. The embryonic midgut is supplied by the superior mesenteric artery.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 31
Correct
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A 48-year-old woman has a mass in her right breast and has right axillary node involvement. She underwent radical mastectomy of her right breast. The histopathology report described the tumour to be 4 cm in its maximum diameter with 3 axillary lymph nodes with evidence of tumour. The most likely stage of cancer in this patient is:
Your Answer: IIB
Explanation:Stage IIB describes invasive breast cancer in which: the tumour is larger than 2 centimetres but no larger than 5 centimetres; small groups of breast cancer cells — larger than 0.2 millimetre but not larger than 2 millimetres — are found in the lymph nodes OR the tumour is larger than 2 centimetres but no larger than 5 centimetres; cancer has spread to 1 to 3 axillary lymph nodes or to lymph nodes near the breastbone (found during a sentinel node biopsy) OR the tumour is larger than 5 centimetres but has not spread to the axillary lymph nodes.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 32
Correct
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A 40-year old lady presented to the hospital with fever and mental confusion for 1 week. On examination, she was found to have multiple petechiae all over her skin and mucosal surfaces. Blood investigations revealed low platelet count and raised urea and creatinine. A platelet transfusion was carried out, following which she succumbed to death. Autopsy revealed pink hyaline thrombi in myocardial arteries. What is the likely diagnosis?
Your Answer: Thrombotic thrombocytopenic purpura
Explanation:Hyaline thrombi are typically associated with thrombotic thrombocytopenic purpura (TTP), which is caused by non-immunological destruction of platelets. Platelet transfusion is contraindicated in TTP. Platelets and red blood cells also get damaged by loose strands of fibrin deposited in small vessels. Multiple organs start developing platelet-fibrin thrombi (bland thrombi with no vasculitis) typically at arteriocapillary junctions. This is known as ‘thrombotic microangiopathy’. Treatment consists of plasma exchange.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 33
Correct
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A CT-scan of the lung shows a tumour crossing the minor (horizontal) fissure. This fissure separates:
Your Answer: The middle lobe from the upper lobe
Explanation:The horizontal fissure separates the upper lobe from the middle lobe. The oblique fissure on the other hand separates the lower lobe from both the middle and upper lobes. The lingula is found only on the left lung.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 34
Correct
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From which source does the lingual artery originate?
Your Answer: External carotid
Explanation:The lingual artery arises from the external carotid between the superior thyroid artery and facial artery. It can be located easily on the lower surface of the tongue. The terminal branch of the lingual artery is the deep lingual artery. On its course the lingual artery gives off side branches: dorsal lingual branches that supply the dorsum of the tongue till the epiglottis; sublingual artery that supplies the sublingual gland.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 35
Correct
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In what form are fats primarily transported in the body?
Your Answer: Free fatty acids
Explanation:Fat is mainly transported in the body as free fatty acids. Once out of the adipose cell, the free fatty acids get ionized and combine with albumin.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 36
Correct
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A surgeon trainee is assisting in an operation to ligate the ductus arteriosus. The consultant supervising explains that caution is required when placing a clamp on the ductus to avoid injury to an important structure immediately dorsal to it. To which structure is the consultant referring?
Your Answer: Left recurrent laryngeal nerve
Explanation:The left recurrent laryngeal nerve branches off the vagus and wraps around the aorta, posterior to the ductus arteriosus/ligamentum arteriosum from whence it courses superiorly to innervate the laryngeal muscles.
Accessory Hemiazygous vein is on the left side of the body draining the posterolateral chest wall and emptying blood into the azygos vein.
The left internal thoracic artery is branch of the left subclavian artery supplying blood to the anterior wall of the thorax.
Left phrenic nerve is lateral to the vagus nerve.
Thoracic duct: is behind the oesophagus, coursing between the aorta and the azygos vein in the posterior chest.
Right recurrent laryngeal nerve: loops around the right subclavian artery and is not in danger in this procedure.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 37
Correct
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Bloody discharge from the nipple of a 40-year old woman with no obvious lump or abnormality on mammography is suggestive of:
Your Answer: Intraductal papilloma
Explanation:A small benign tumour, namely intraductal papilloma is most common in women between 35-55 years of age. It is also the commonest cause of spontaneous discharge from a single duct. A lump below the nipple may be sometimes palpable. Ultrasound and ductography are useful investigations., along with cytology of discharge to assess the presence of malignant cells. Confirmation is by breast biopsy.
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This question is part of the following fields:
- Pathology
- Women's Health
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Question 38
Correct
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The Henderson–Hasselbalch equation describes the derivation of pH as a measure of acidity. According to this equation, the buffering capacity of the system is at maximum when the number of free anions compared with undissociated acid is:
Your Answer: Equal
Explanation:In 1908, Lawrence Joseph Henderson wrote an equation describing the use of carbonic acid as a buffer solution. Later, Karl Albert Hasselbalch re-expressed that formula in logarithmic terms, resulting in the Henderson–Hasselbalch equation. The equation is also useful for estimating the pH of a buffer solution and finding the equilibrium pH in acid–base reactions. Two equivalent forms of the equation are: pH = pKa + log10 [A–]/[HA] or pH = pKa + log10 [base]/[acid]. Here, pKa is − log10(Ka) where Ka is the acid dissociation constant, that is: pKa = –log10(Ka) = –log10 ([H3 O+][A–]/[HA]) for the reaction: HA + H2 O ≈ A– + H3 O+ In these equations, A– denotes the ionic form of the relevant acid. Bracketed quantities such as [base] and [acid] denote the molar concentration of the quantity enclosed. Maximum buffering capacity is found when pH = pKa or when the number of free anions to undissociated acid is equal and buffer range is considered to be at a pH = pKa ± 1.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 39
Correct
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Action potentials are used extensively by the nervous system to communicate between neurones and muscles or glands. What happens during the activation of a nerve cell membrane?
Your Answer: Sodium ions flow inward
Explanation:During the generation of an action potential, the membrane gets depolarized which cause the voltage gated sodium channels to open and sodium diffuses inside the neuron, resulting in the membrane potential moving towards a positive value. This positive potential will then open the voltage gated potassium channels and cause more K+ to move out decreasing the membrane potential and restoring the membrane potential to its resting value.
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This question is part of the following fields:
- General
- Physiology
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Question 40
Correct
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A 42 year old women presents with end stage renal failure and is prepared to receive a kidney from her husband. HLA testing showed that they are not a 100% match and she is given immunosuppressant therapy for this. Three months later when her renal function tests were performed she showed signs of deteriorating renal function, with decreased renal output, proteinuria of +++ and RBCs in the urine. She was given antilymphocyte globulins and her condition reversed. What type of graft did this patient receive?
Your Answer: Allograft
Explanation:Allograft describes a graft between two of the same species. As the donor and the recipients are history-incompatible, rejection of the graft is common and is controlled by immunosuppressive drug therapy. Isograft and syngraft are synonymous and referred to a graft transferred between genetically identical individuals e.g. identical twins. In this case rejection is rare as they are history-compatible.
Autograft refers to transfer of one part of the body to another location.
Xenograft is transfer of tissue from another species e.g. pig to human in valve replacement surgeries and rejection is very high.
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This question is part of the following fields:
- Inflammation & Immunology; Renal
- Pathology
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