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Question 1
Correct
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Following a bee sting, a women develops a 2cm red, raised, swollen lesion at the site of the sting . Which of the following findings is likely to be seen in this lesion?
Your Answer: Vasodilation
Explanation:Inflammation is the immediate response of the body towards infections or irritations. The cardinal signs of inflammation are 1. redness/rubor, 2. tumour/swelling, 3.dolar/pain, 4.calor/heat and organ dysfunction (function laesa). Inflammation has 2 components; vascular and cellular. Blood vessels dilate upstream of the inflamed area leading to the rubor and calor and constrict downstream, increasing pressure and causing fluid to leak out of the capillary, resulting in swelling. The cellular component includes infiltration by neutrophils. Leukocyte arrival and functions include; 1. margination: cells marginated from the centre to the periphery of the vessel, 2. rolling: selectins are upregulated on the vessel walls, 3. adhesion: upregulation of the adhesion molecules ICAM and VCAM on the endothelium interact with integrins on the leukocytes resulting in adhesion, 4. diapedesis and chemotaxis: diapedesis is the transmigration of the leukocyte across the endothelium of the capillary and towards a chemotactic product and 5. phagocytosis: engulfing the offending substance/cell.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 2
Correct
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A 35-year old lady presents to her GP with vague abdominal symptoms. Examination reveals a normal size spleen. Which of the following is the likely diagnosis?
Your Answer: Idiopathic thrombocytopenic purpura
Explanation:Idiopathic thrombocytopenic purpura (ITP) is a disease caused due to development of an antibody against a platelet antigen (autoantibody). In childhood disease, the autoantibody gets triggered by binding of viral antigen to the megakaryocytes. Presentation includes unexplained thrombocytopenia, petechiae and bleeding from mucosal surfaces. The spleen usually does not enlarge in size. However, splenomegaly can occur due to coexisting viral infection. Marrow examination reveals normal or increased number of megakaryocytes. Diagnosis is by exclusion of other thrombocytopenic disorders.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 3
Correct
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A 45 year old female had a stroke and was diagnosed with a homonymous hemianopsia. Which of the following structures was likely affected?
Your Answer: Optic radiation
Explanation:Hemianopia or hemianopsia, is the loss of vision of half of the eye or loss of half the visual field. Homonymous hemianopia is the loss of vision or blindness on half of the same side of both eyes (visual field) – either both lefts of the eyes or both rights of the eyes. This condition is mainly caused by cerebrovascular accidents like a stroke that affects the optic radiation.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 4
Correct
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The pterion is clinically significant as it marks an area of weakness on the skull. What structure lies beneath it?
Your Answer: Anterior branches of the middle meningeal artery
Explanation:The pterion is the area where four bones, the parietal, frontal, greater wing of sphenoid and the squamous part of the temporal bone meet. It overlies the anterior branch of the middle meningeal artery on the internal aspect of the skull. The pterion is the weakest part of the skull. Slight trauma to this region can cause extradural hematoma.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 5
Correct
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The blood-brain barrier is a membrane that separates the circulating blood from the brain extracellular fluid in the central nervous system (CNS). Which of the following statements regarding the blood– brain barrier is CORRECT?
Your Answer: It breaks down in areas of brain that are infected
Explanation:The blood–brain barrier is a membrane that controls the passage of substances from the blood into the central nervous system. It is a physical barrier between the local blood vessels and most parts of the central nervous system and stops many substances from travelling across it. During meningitis, the blood–brain barrier may be disrupted. This disruption may increase the penetration of various substances (including either toxins or antibiotics) into the brain. A few regions in the brain, including the circumventricular organs, do not have a blood–brain barrier.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 6
Correct
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Prostatectomy carries a risk of loss of penile erection due to injury to the prostatic plexus responsible for an erection. From which nerves do these fibres originate?
Your Answer: Pelvic splanchnics
Explanation:Erection is a function of the parasympathetic nerves. Of the nerves listed, only the pelvic splanchnic nerves have parasympathetic fibres that innervate the smooth muscles and glands of the pelvic viscera.
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This question is part of the following fields:
- Anatomy
- Pelvis
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Question 7
Incorrect
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What are the derivatives of the first brachial arch?
Your Answer: Gives rise to the styloid process and hyoid bone
Correct Answer: Gives rise to the sphenomandibular ligament
Explanation:The first brachial arch (mandibular) gives rise to the mandibular and maxillary processes. Muscles and bones of this process originate within the arch’s mesoderm. The first arch cartilage (Meckel’s) ossifies to form the incus and malleus of the middle ear. Its perichondrium gives rise to he sphenomandibular ligament and through intermembraneous ossification after the mandible forms, the rest of the cartilage disappears. Muscles of the first arch include: mylohyoid, tensor tympany and palati, temporalis, masseter and lateral pterygoids and the anterior belly of the epigastric. This first arch is supplied by the trigeminal nerve.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 8
Correct
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A 65-year old patient with altered bowl movement experienced the worsening of shortness of breath and exertional chest pains over the course of 8 weeks. Examination shows pallor and jugular venous distension. Furthermore, a test of the stool for occult blood is positive. Laboratory studies show:
Haemoglobin 7.4 g/dl
Mean corpuscular volume 70 fl Leukocyte count 5400/mm3
Platelet count 580 000/mm3 Erythrocyte sedimentation 33 mm/h
A blood smear shows hypochromic, microcytic RBCs with moderate poikilocytosis. Which of the following is the most likely diagnosis?Your Answer: Iron deficiency anaemia
Explanation:Iron deficiency anaemia is the most common type of anaemia. It can occur due to deficiency of iron due to decreased intake or due to faulty absorption. An MCV less than 80 will indicated iron deficiency anaemia. On the smear the RBC will be microcytic hypochromic and will also show piokilocytosis. iron profiles tests are important to make a diagnosis. Clinically the patient will be pale and lethargic.
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This question is part of the following fields:
- General
- Physiology
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Question 9
Correct
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The posterior boundary of the carotid triangle is bounded by which of the following muscles?
Your Answer: Sternocleidomastoid
Explanation:The carotid triangle is a portion of the anterior triangle of the neck. It is bounded superiorly by the posterior belly of the digastric muscle, antero-inferiorly by the superior belly of omohyoid and posteriorly by the sternocleidomastoid. The floor is formed by the thyrohyoid, hyoglossus, middle and inferior pharyngeal constrictors and the roof is formed by the skin, superficial fascia, platysma and deep fascia.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 10
Correct
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A 35 year-old man presents with high grade fever for 7 days after returning from a trip to India. He tested positive for widal test. What is the most likely organism that caused his fever?
Your Answer: Salmonella typhi
Explanation:Typhoid fever is caused by virulent bacteria called Salmonella typhi. Salmonella typhi spread through contaminated food or water and occasionally through direct contact with someone who is infected.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 11
Correct
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Which of the following brings about a reduction in gastric blood flow?
Your Answer: Vasopressin
Explanation:Gastric blood flow is increased by vagal stimulation, gastrin, histamine and acetylcholine as they stimulate gastric section and the production of vasodilator metabolites. Acetylcholine and histamine also have a direct action on the gastric arterioles. Similarly, gastric blood flow is reduced by inhibitors of secretion – catecholamines, secretin and vasopressin.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 12
Correct
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A tumour growing in the posterior mediastinum is found in a 40-year-old man who presented to the out patient clinic with chest pain. Such a tumour is likely to compress the following structure:
Your Answer: Oesophagus
Explanation:The boundaries of the posterior mediastinum are: the superiorly through the sternal angle and T4/5, inferiorly, the diaphragm, anteriorly, by the middle mediastinal structures and posteriorly by the spinal cord. Structures in the posterior mediastinum include the descending thoracic aorta, the azygos system, oesophagus, thoracic duct and lymph nodes. The great vessels and structures at the root of the lung are part of the middle mediastinum. The oesophagus is the only structure in the posterior mediastinum among the choices.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 13
Incorrect
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Inside the palatoglossal arch is a muscle. Which nerve innervates this muscle?
Your Answer: IX
Correct Answer: X
Explanation:The palatoglossal arch contains the palatoglossal muscle which is innervated by the vagus nerve which is the tenth cranial nerve. So the correct answer is X
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 14
Correct
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A 34-year-old woman with severe burns, presented to casualty with a blood pressure of 75/40 mmHg and pulse of 172/minute. Obviously the patient is in shock. Which type of shock is it more likely to be?
Your Answer: Hypovolaemic shock
Explanation:Shock is a life-threatening condition that occurs when the organs and tissues of the body are not receiving a sufficient flow of blood. Lack of blood flow, oxygen and nutrients results in the inability to function properly and damage to many organs. Shock requires immediate treatment because, if left untreated the impaired tissue perfusion and cellular hypoxia can cause irreversible tissue injury, collapse, coma or even death. There are various types of physiological shock, including: cardiogenic (due to heart damage), hypovolaemic (due to low total volume of blood or plasma), neurogenic (due to nervous system damage), septic (due to infections) and anaphylactic shock (due to allergic reactions). Hypovolaemic shock can be caused by blood loss due to trauma, internal bleeding or other fluid loss due to severe burns, prolonged diarrhoea, vomiting and sweating.
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This question is part of the following fields:
- Cardiovascular
- Pathology
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Question 15
Correct
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A 39-year old female patient was diagnosed with a tumour of the left adrenal gland. The tumour, which is metastasizing to the adjacent tissues, has already extended to the left suprarenal vein. If the tumour is still spreading, which of the following veins will most likely be affected after the involvement of the left suprarenal vein?
Your Answer: Left renal vein
Explanation:The suprarenal veins or also known as the veins of Warshaw, are the veins that receive blood from the suprarenal glands. These veins receive blood from the medullary venous plexus and the cortex of the adrenal glands (suprarenal glands). They are two in number – the left and the right suprarenal veins. The right suprarenal vein drains into the inferior vena cava while the left suprarenal vein drains into the left renal vein. This therefore means that in the case of a metastasizing tumour involving the left suprarenal vein, the tumour will most likely extend from the left suprarenal vein to the left renal vein into which it drains.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 16
Correct
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This structure divides the space between the lens and the cornea into the anterior and posterior chambers of the eye:
Your Answer: The iris
Explanation:The iris divides the space between the lens and the cornea into an anterior and a posterior chamber. The anterior cavity is filled with watery aqueous fluid, and the posterior cavity with a gel-like vitreous fluid. The anterior chamber of the eye is bounded in front by the posterior surface of the cornea; behind by the front of the iris and the central part of the lens. The posterior chamber is a narrow gap behind the peripheral part of the iris and in front of the suspensory ligament of the lens and the ciliary processes.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 17
Correct
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An alcoholic patient was found to have hypomagnesaemia on blood tests. Which of the following clinical features will have prompted the doctor to check the serum magnesium level in this patient?
Your Answer: Seizures
Explanation:Hypomagnesaemia is a condition characterised by a low level of magnesium in the blood. The normal range for serum magnesium level is 0.75-1.05 mmol/l. In hypomagnesaemia serum levels of magnesium are less than 0.75 mmol/l. The cardiovascular and nervous systems are the most commonly affected. Neuromuscular manifestations include symptoms like tremor, tetany, weakness, apathy, delirium, a positive Chvostek and Trousseau sign, nystagmus and seizures. Cardiovascular manifestations include electrocardiographic abnormalities and arrhythmias e.g. ventricular fibrillation.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 18
Incorrect
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A 42-year old woman presents to the doctor with jaundice. Her investigations show conjugated hyperbilirubinemia, raised urine bilirubin levels and low urine urobilinogen levels. What is the likely cause of her jaundice?
Your Answer: Deficiency of glucuronyl transferase
Correct Answer: Blockage of the common bile duct
Explanation:The description of the patient here fits the diagnosis of obstructive jaundice or cholestasis, which results in conjugated hyperbilirubinemia. Cholestasis occurs due to impairment of bile flow, which can be anywhere from the liver cell canaliculus to the ampulla of Vater. Causes can be divided into intrahepatic and extrahepatic.
– Intrahepatic causes include hepatitis, drug toxicity, alcoholic liver disease, primary biliary cirrhosis, cholestasis of pregnancy and metastatic cancer.
– Extrahepatic causes include common duct stone, pancreatic cancer, benign stricture of the common duct, ductal carcinoma, pancreatitis and sclerosing cholangitis.
There is absence of bile constituents in the intestine, which causes spillage in the systemic circulation. Symptoms include pale stools, dark urine, pruritus, malabsorption leading to steatorrhea and deficiency of fat-soluble vitamins. Chronic cases can result in osteoporosis or osteomalacia due to vitamin D deficiency and Ca2+ malabsorption. Cholesterol and phospholipid retention produces hyperlipidaemia despite fat malabsorption (although increased liver synthesis and decreased plasma esterification of cholesterol also contribute); triglyceride levels are largely unaffected. The lipids circulate as a unique, low-density lipoprotein called lipoprotein X.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 19
Correct
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A 30 year old male has a painless and transilluminant swelling at the upper pole of his left testi. There is a negative cough test. Which of the following is the likely diagnosis?
Your Answer: Spermatocoele
Explanation:Spermatocele, also known as a spermatic cyst is a cystic mass usually occurring at the upper pole of the testis. Differential diagnosis included hydrocele as both are cystic, painless and transilluminant. Ultrasound is a useful modality. If symptomatic or large, surgical excision can be done.
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This question is part of the following fields:
- Pathology
- Urology
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Question 20
Correct
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A patient presents with loss of fine touch and sense of proprioception in the lower part of the body (below T6). He is likely to have a lesion involving:
Your Answer: Gracile nucleus
Explanation:The gracile nucleus is located in the medulla oblongata and is one of the dorsal column nuclei involved in the sensation of fine touch and proprioception. It contains second-order neurons of the dorsal column–medial lemniscus system, that receive inputs from sensory neurones of the dorsal root ganglia and send axons that synapse in the thalamus.
The gracile nucleus and fasciculus carry epicritic, kinaesthetic and conscious proprioceptive information from the lower part of the body (below the level of T6 in the spinal cord). Similar information from the upper part of body (above T6, except for face and ear) is carried by the cuneate nucleus and fasciculus. The information from face and ear is carried by the primary sensory trigeminal nucleus.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 21
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 22
Correct
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Which of these HLA alleles is most likely to be present in ankylosing spondylitis?
Your Answer: HLA-B27
Explanation:Ankylosing spondylitis usually appears between the ages of 20-40 years old and is more frequent in men. It is strongly associated with HLA-B27, along with other spondyloarthropathies, which can be remembered through the mnemonic PAIR (Psoriasis, Ankylosing spondylitis, Inflammatory bowel disease, and Reactive arthritis).
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This question is part of the following fields:
- Orthopaedics
- Pathology
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Question 23
Correct
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Which of the following is the cause of flattened (notched) T waves on electrocardiogram (ECG)?
Your Answer: Hypokalaemia
Explanation:The T-wave is formed due to ventricular repolarisation. Normally, it is seen as a positive wave. It can be normally inverted (negative) in V1 (occasionally in V2-3 in African-Americans/Afro-Caribbeans). Hyperacute T-waves are the earliest ECG change of acute myocardial infarction. ECG findings of hyperkalaemia include high, tent-shaped T-waves, a small P-wave and a wide QRS complex. Hypokalaemia results in flattened (notched) T-waves, U-waves, ST-segment depression and prolonged QT interval.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 24
Correct
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The most likely cause of a low p(O2) in arterial blood is:
Your Answer: Hypoxic hypoxia
Explanation:Hypoxia is when the whole body or a region is deprived of adequate oxygen supply. Different types of hypoxia include the following:
– Hypoxic hypoxia, which occurs due to poor oxygen supply, as a result of low partial pressure of oxygen in arterial blood. This could be due to low partial pressure of atmospheric oxygen (e.g., at high altitude), sleep apnoea, poor ventilation because of chronic obstructive pulmonary disease or respiratory arrest, or shunts. The other types of hypoxia have a normal partial pressure of oxygen.
– Anaemic hypoxia occurs due to low total oxygen content of the blood, with a normal arterial oxygen pressure.
– Hyperaemic hypoxia occurs due to poor delivery of oxygen to target tissues, such as in carbon monoxide poisoning or methemoglobinemia.
– Histotoxic hypoxia results due to inability of the cells to use the delivered oxygen due to disabled oxidative phosphorylation enzymes.
– Ischaemic (or stagnant) hypoxia occurs due to local flow restriction of well-oxygenated blood, seen in cases like cerebral ischaemia, ischaemic heart disease and intrauterine hypoxia.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 25
Correct
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Evaluation of a 60-year old gentleman, who has been a coal miner all his life and is suspected to have pulmonary fibrosis reveals the following: normal FEV1, arterial oxygen saturation 92%, alveolar ventilation 6000 ml/min at a tidal volume of 600 ml and a breathing rate of 12 breaths/min. There are also pathological changes in lung compliance and residual volume. Which of the following is most accurate about his residual volume?
Your Answer: Cannot be measured directly with a spirometer
Explanation:Residual volume is the air left in the lungs after maximal expiration is done. Thus, this is not a part of vital capacity and cannot be measured with a spirometer directly. It can be measured by the methods such as body plethysmography or inert gas dilution. Expiratory reserve volume is vital capacity minus inspiratory capacity. Resting volume of lungs is he sum of residual volume and expiratory reserve volume. Lungs recoil inward until the recoil pressure becomes zero, which corresponds to a volume significantly lower than residual volume.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 26
Correct
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A 56-year-old woman complains of back pain, muscle spasms, weakness, and a burning sensation that radiates from her left hip to her toes. What's the most likely diagnosis?
Your Answer: Herniated nucleus pulposus
Explanation:A herniated disk will produce sensory disturbances, causing pain that radiates along the course of the sciatic nerve which is typically burning or stabbing, with or without back pain. The herniation is usually caused by age-related degeneration although trauma, injuries, or straining may also trigger it.
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This question is part of the following fields:
- Orthopaedics
- Pathology
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Question 27
Incorrect
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A 25 year-old male patient was brought to the hospital due to a vehicular accident. A skull x-ray was done which revealed a fracture along the base of the middle cranial fossa. The patient has no sense of touch over the skin over his cheek and chin. Injury to the maxillary and the mandibular nerves is suspected. In which foramina do these two affected sensory branches leave the cranial cavity.
Your Answer: Foramen ovale and the hiatus for the greater petrosal nerve
Correct Answer: Foramen rotundum and foramen ovale
Explanation:The patient’s clinical manifestations suggests an injury to the maxillary and mandibular nerves. The maxillary branch (V2) of the trigeminal nerve (CN V) passes through and exits the skull via the pterygopalatine fossa and the foramen rotundum. At the base of the skull the foramen ovale (Latin: oval window) is one of the larger of the several holes (the foramina) that transmit nerves through the skull. The foramen ovale is situated in the posterior part of the sphenoid bone, posterolateral to the foramen rotundum. The following structures pass through foramen ovale: mandibular nerve, motor root of the trigeminal nerve, accessory meningeal artery (small meningeal or paradural branch, sometimes derived from the middle meningeal artery), lesser petrosal nerve, a branch of the glossopharyngeal nerve and an emissary vein connecting the cavernous sinus with the pterygoid plexus of veins. Occasionally it will also carry the anterior trunk of the middle meningeal vein.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 28
Incorrect
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An anatomy instructor is giving a demonstration of the right lung. Which of the statements about the right lung made by the demonstrator is correct?
Your Answer: Its upper lobar bronchus lies behind and below the right pulmonary artery
Correct Answer: Its upper lobar bronchus lies behind and above the right pulmonary artery
Explanation:The root of the lungs on both sides are similar in that the pulmonary veins are anterior and inferior while the bronchus is posterior. However, on the right side, the pulmonary arteries are anterior to the bronchus while on the left side the pulmonary arteries are superior to the bronchus. The lingual is only found on the left lung. The mediastinum is the space in the thorax between the two pleural sacs and does not contain any lung. The right lung, having three lobes, is slightly larger than the left lung. On both sides, the phrenic nerves passes in front of the root of the lung.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 29
Incorrect
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What is the normal duration of the ST segment?
Your Answer: 0.02 s
Correct Answer: 0.08 s
Explanation:The ST segment lies between the QRS complex and the T-wave. The normal duration of the ST segment is 0.08 s. ST-segment elevation or depression may indicate myocardial ischaemia or infarction.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 30
Incorrect
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During an inguinal hernia repair, an incision is made parallel to and 5cm above the inguinal ligament. The registrar is warned to look out for the inferior epigastric vessels to avoid damage. Between which layers of the abdominal wall is the registrar likely to find these vessels?
Your Answer: External abdominal oblique and internal abdominal oblique muscles
Correct Answer: Transversus abdominis muscle and peritoneum
Explanation:The inferior epigastric vessels lie on the inner surface of the transversus abdominis muscle covered by the parietal peritoneum. This layer of peritoneum lies over the inferior epigastric vessels to make the lateral umbilical fold. Camper’s and Scarpa’s fascia are two layers of the superficial fascia, the fatty layer and the membranous layer respectively.
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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 medical intern wanting to perform her first thoracentesis (remove fluid from the pleural cavity) wishes to be reminded where to insert the needle to aspirate in order to avoid injuring the lung or neurovascular elements. Where is this place?
Your Answer: The bottom of interspace 9 in the midaxillary line
Explanation:Thoracentesis is performed in the costodiaphragmatic recess. The needle needs to be inserted below the level of the lungs to avoid injury to the lungs. At the paravertebral line, is between ribs 10 and 12, at the midaxillary line between ribs 8 and 10 and at the midclavicular line between interspaces 6 and 8. The needle should be inserted at the top of the rib (or the bottom of the interspace) to avoid damage to the neurovascular structures found below the rib running in the costal groove.
The recommended location for the needle insertion varies depending upon the source. It is critical that the patient hold his or her breath to avoid piercing of the lung.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 32
Incorrect
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A machine worker fractured the medial epicondyle of his right humerus resulting in damage to an artery running with the ulnar nerve posterior to the medial epicondyle. The artery injured is the?
Your Answer: Anterior ulnar recurrent
Correct Answer: Superior ulnar collateral
Explanation:The superior ulnar collateral artery runs posterior to the medial epicondyle of the humerus, accompanied by the ulnar nerve. This artery arises from the brachial artery near the middle of the arm and ends under the flexor carpi ulnaris muscle by anastomosing with two arteries: the posterior ulnar recurrent and inferior ulnar collateral.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 33
Incorrect
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Which of the following is true about a patient who has undergone total colectomy and ileostomy?
Your Answer: This patient is at increased risk of anaemia due to malabsorption of vitamin B12
Correct Answer: Following total colectomy and ileostomy, the volume and water content of ileal discharge decreases over time
Explanation:After a patient has undergone total colectomy and ileostomy, the volume of ileal discharge, along with its water content gradually decreases over time. Post surgery, most patients can live a normal life. Iron and vitamin B12 absorption do not take place in the colon and hence are not affected significantly by a colectomy.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 34
Correct
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During a normal respiratory exhalation, what is the recoil alveolar pressure?
Your Answer: +10 cmH2O
Explanation:To determine compliance of the respiratory system, changes in transmural pressures (in and out) immediately across the lung or chest cage (or both) are measured simultaneously with changes in lung or thoracic cavity volume. Changes in lung or thoracic cage volume are determined using a spirometer with transmural pressures measured by pressure transducers. For the lung alone, transmural pressure is calculated as the difference between alveolar (pA; inside) and intrapleural (ppl; outside) pressure. To calculate chest cage compliance, transmural pressure is ppl (inside) minus atmospheric pressure (pB; outside). For the combined lung–chest cage, transmural pressure or transpulmonary pressure is computed as pA – pB. pA pressure is determined by having the subject deeply inhale a measured volume of air from a spirometer. Under physiological conditions the transpulmonary or recoil pressure is always positive; intrapleural pressure is always negative and relatively large, while alveolar pressure moves from slightly negative to slightly positive as a person breathes.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 35
Correct
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During an anatomy revision session, medical students are told that the posterior wall of the rectus sheath ends in a thin curved margin whose concavity is directed downwards. What is the name of this inferior border of the rectus sheath?
Your Answer: Arcuate line
Explanation:The rectus sheath is a tendinous sheath that encloses the rectus abdominis muscle. It covers the entire anterior surface however on the posterior surface of the muscle the sheath is incomplete ending inferiorly at the arcuate line. Below the arcuate line, the rectus abdominis is covered by the transversalis fascia. The linea alba is a band of aponeurosis on the midline of the anterior abdominal wall, which extends from the xiphoid process to the pubic symphysis. It is formed by the combined abdominal muscle aponeuroses. This is a useful site for midline incision during abdominal surgery because it does not carry many blood vessels. All of the other answer choices are related to the inguinal canal.
The falx inguinalis (sometimes called the inguinal falx or conjoint tendon), is the inferomedial attachment of the transversus abdominis with some fibres of the internal abdominal oblique – it contributes to the posterior wall of the inguinal canal.
The inguinal ligament is the ligament that connects the anterior superior iliac spine with the pubic tubercle – it makes the floor of the inguinal canal.
The internal (deep) inguinal ring is the entrance to the inguinal canal, where the transversalis fascia pouches out and creates an opening through which structures can leave the abdominal cavity.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 36
Incorrect
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A 27 year-old male patient was admitted to the hospital due to recurrent fever for the past 2 weeks. The patient claimed that he is an intravenous drug user. Following work up, the patient was diagnosed with infective endocarditis. Which is the most likely organism responsible for this diagnosis?
Your Answer: Enterococcus
Correct Answer: Staphylococcus aureus
Explanation:Acute bacterial endocarditis is a fulminant illness lasting over days to weeks (<2weeks). It is most likely due to Staphylococcus aureus especially in intravenous drug abusers.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 37
Incorrect
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A 27 year old women works in a dry-cleaning shop. She was exposed to massive amounts of carbon tetrachloride on her skin as well as inhaled. Which of the following organs is most susceptible to damage?
Your Answer: Kidney
Correct Answer: Liver
Explanation:Carbon tetrachloride (CCl4) is a common agent used in the dry cleaning industry and is thought to cause the formation of free radicals. It causes rapid breakdown of the endoplasmic reticulum due to decomposition of lipids and severe liver cell injury. Within less than 30 mins, hepatic protein synthesis declines, lipid export is reduced due to lack of apoprotein and there is an influx of calcium and cell death.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 38
Correct
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A 50 year-old man, who sustained a head injury experienced sudden onset of horizontal double vision. He is diagnosed with lateral rectus palsy. Which of the following nerves is affected in this condition?
Your Answer: Abducent
Explanation:The lateral rectus muscle is one of the 6 extra-ocular muscles that control eye movements. It is responsible for abduction and is the only muscle that is innervated by the abducens nerve (CN VI).
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 39
Correct
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The fundus of the stomach receives blood supply from the same artery as the greater curvature of the stomach. Which of the following arteries when ligated will disrupt blood supply to the fundus of the stomach through this artery?
Your Answer: Splenic
Explanation:The fundus of the stomach along with the greater curvature of the stomach receive blood supply from the short gastric artery. The short gastric artery arises from the end of the splenic artery. The ligation of the splenic artery therefore would cause a disruption of blood supply to the fundus of the stomach.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 40
Correct
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After severe injury of the upper limb following an accident. The humerus is injured as well as the nerve which innervates the muscles of the anterior compartment of the arm. Which nerve is injured?
Your Answer: Musculocutaneous
Explanation:The musculoskeletal nerve supplies the muscles of the anterior compartment of the arm including the coracobrachialis, biceps brachii and the greater part of the brachialis. This nerve derives its fibres from the fifth, sixth and seventh cervical nerves and arises from the lateral cord of the brachial plexus. It also provides a branch to the elbow joint.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 41
Correct
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A 27-year-old woman, who had been taking a combined oral contraceptive for 6 months, presented with inguinal pain and oedema of the left leg. Which of the following investigations would you recommend to help confirm the diagnosis?
Your Answer: Duplex scan
Explanation:Oral combined contraceptive pill (OCCP) is a drug used for birth control and treating a number of other conditions. Women who take the OCP have a higher risk of developing deep vein thrombosis (DVT), usually in the legs. Duplex ultrasonography is a safe and non-invasive technique which is used for diagnosing the presence of lower extremity thrombi.
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This question is part of the following fields:
- Cardiovascular
- Pathology
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Question 42
Correct
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A 27-year-old woman has chronic low serum calcium levels. Which of the following conditions may be responsible for the hypocalcaemia in this patient?
Your Answer: Hypoparathyroidism
Explanation:Chronic hypocalcaemia is mostly seen in patients with hypoparathyroidism as a result of accidental removal or damage to parathyroid glands during thyroidectomy.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 43
Incorrect
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The bronchial circulation is a part of the circulatory system that supplies nutrients and oxygen to the pulmonary parenchyma. What percentage of cardiac output is received by bronchial circulation?
Your Answer: 7%
Correct Answer: 2%
Explanation:The bronchial circulation is part of the systemic circulation and receives about 2% of the cardiac output from the left heart. Bronchial arteries arise from branches of the aorta, intercostal, subclavian or internal mammary arteries. The bronchial arteries supply the tracheobronchial tree with both nutrients and O2. It is complementary to the pulmonary circulation that brings deoxygenated blood to the lungs and carries oxygenated blood away from them in order to oxygenate the rest of the body.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 44
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 45
Correct
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A 62-year-old male smoker, presented with shortness of breath, chronic cough and haemoptysis over the last three months. He has developed a fat pad in the base of his neck, rounded face, acne and osteoporosis. Which of the following is the most likely pulmonary disease that is causing these symptoms and findings?
Your Answer: Small-cell anaplastic carcinoma
Explanation:Small cell lung cancer is a highly aggressive form of lung cancer. It is thought to originate from neuroendocrine cells in the bronchus called Feyrter cells and is often associated to ectopic production of hormones like ADH and ACTH that result in paraneoplastic syndromes and Cushing’s syndrome.
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This question is part of the following fields:
- Pathology
- Respiratory
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Question 46
Correct
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Which of these conditions causes haematuria, hypertension and proteinuria in children, usually after a streptococcal infection?
Your Answer: Acute nephritic syndrome
Explanation:Nephritic syndrome (or acute nephritic syndrome) is a syndrome comprising of signs of nephritis. Children between 2 and 12 are most commonly affected, but it may occur at any age. Predisposing factors/causes include:
Infections with group A streptococcal bacteria (acute post-streptococcal glomerulonephritis).
Primary renal diseases: immunoglobulin A nephropathy, membranoproliferative glomerulonephritis, idiopathic rapidly progressive crescentic glomerulonephritis.
Secondary renal diseases: subacute bacterial endocarditis, infected ventriculo–peritoneal shunt, glomerulonephritis with visceral abscess, glomerulonephritis with bacterial, viral or parasitic infections.
Multisystem diseases.
By contrast, nephrotic syndrome is characterized by only proteins moving into the urine.
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This question is part of the following fields:
- Physiology
- Renal
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Question 47
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 48
Correct
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A surgeon performing a thymectomy to remove a malignant thymoma is careful to avoid damaging an important nerve lying around the arch of the aorta. Which nerve is the surgeon trying to preserve?
Your Answer: Left Vagus
Explanation:The left vagus nerve lies on the lateral surface of the aortic arch. The left recurrent laryngeal nerve arises from the vagus and loops around the arch of the aorta. This nerve is at risk of injury during surgery.
The right and left phrenic nerves, being lateral to the vagus, do not loop around the arch of the aorta.
The sympathetic trunks, both right and left, are located in the posterior chest; not near the aortic arch.
The right vagus: not involved with the aortic arch.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 49
Incorrect
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Which of the following muscles winds around the pterygoid hamulus?
Your Answer: Salpingopharyngeus
Correct Answer: Tensor veli palatini
Explanation:The tensor veli palatini tenses the soft palate and by doing so, assists the levator veli palatini in elevating the palate to occlude and prevent entry of food into the nasopharynx during swallowing. It arises by a flat lamella from the scaphoid fossa at the base of the medial pterygoid plate, from the spina angularis of the sphenoid and from the lateral wall of the cartilage of the auditory tube. Descending vertically between the medial pterygoid plate and the medial pterygoid muscle, it ends in a tendon which winds around the pterygoid hamulus, being retained in this situation by some of the fibres of origin of the medial pterygoid muscle. Between the tendon and the hamulus is a small bursa. The tendon then passes medialward and is inserted onto the palatine aponeurosis and the surface behind the transverse ridge on the horizontal part of the palatine bone.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 50
Incorrect
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The anatomical dead space in a patient with low oxygen saturation, is 125 ml, with a tidal volume of 500 ml and pa(CO2) of 40 mm Hg. The dead space was determined by Fowler's method. If we assume that the patient's lungs are healthy, what will his mixed expired CO2 tension [pE(CO2)] be?
Your Answer: 60 mmHg
Correct Answer: 30 mmHg
Explanation:According to Bohr’s equation, VD/VT = (pA(CO2) − pE(CO2))/pA(CO2), where pE(CO2) is mixed expired CO2 and pA(CO2) is alveolar CO2pressure. Normally, the pa(CO2) is virtually identical to pA(CO2). Thus, VD/VT = (pa(CO2)) − pE(CO2)/pa(CO2). By Fowler’s method, VD/VT= 0.25. In the given problem, (pa(CO2) − pE(CO2)/pa(CO2) = (40 − pE(CO2)/40 = 0.25. Thus, pE(CO2) = 30 mmHg. If there is a great perfusion/ventilation inequality, pE(CO2) could be significantly lower than 30 mm Hg, and the patient’s physiological dead space would exceed the anatomical dead space.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 51
Correct
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A 60-year old woman who has a left sided post-pneumonic effusion, was to have some pleural fluid aspirated for culture and sensitivity. If the medical intern in charge of the procedure decided to aspirate while the patient is sitting up on her bed, where in the pleural cavity would the fluid tend to accumulate?
Your Answer: Costodiaphragmatic recess
Explanation:The lowest part of the pleural cavity is the costodiaphragmatic recess and it the space in which the pleural fluid will accumulate when the patient sits up.
The cupola is part of the pleural cavity that extends into the root of the neck above the first rib.
The costomediastinal recess is the junction at which the costal pleura becomes the mediastinal pleura.
The middle mediastinum is the part of the mediastinum that is occupied by the heart.
The hilar reflection is the point where the mediastinal pleura is reflected to continue on as the visceral pleura.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 52
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 53
Correct
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A 29-year-old pregnant woman suffering from hyperemesis gravidarum is prescribed metoclopramide. What is the mechanism of action of metoclopramide?
Your Answer: Dopamine antagonist
Explanation:Metoclopramide is a potent dopamine-receptor antagonist with anti-emetic and prokinetic properties. It is therefore commonly used to treat nausea and vomiting, and to facilitate gastric emptying in patients with gastric stasis. The anti-emetic action of metoclopramide is due to its antagonist activity at D2 receptors in the chemoreceptor trigger zone (CTZ) in the central nervous system. Common adverse drug reactions associated with metoclopramide include restlessness (akathisia), and focal dystonia.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 54
Correct
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A 90-year-old man is prescribed spironolactone after his family notices his legs are swollen. What class of drugs does spironolactone belong to?
Your Answer: Potassium-sparing diuretics
Explanation:Spironolactone is a renal competitive aldosterone antagonist in a class of drugs called ‘potassium-sparing diuretics’, that is primarily used to treat fluid build-up due to heart failure, liver scarring, or kidney disease. It is also used in the treatment of high blood pressure, low blood potassium, early-onset puberty, and acne and excessive hair growth in women. Spironolactone inhibits the effect of aldosterone by competing for intracellular aldosterone receptors in the distal tubule cells. This increases the secretion of water and sodium, while decreasing the excretion of potassium.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 55
Correct
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Due to a plantarflexion–inversion ankle sprain, which is the first ligament to rupture?
Your Answer: Anterior talofibular ligament
Explanation:The anterior talofibular ligament passes from the anterior margin of the fibular malleolus. It is the most commonly injured ligament, as part of the lateral ligament of the ankle.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 56
Incorrect
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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 protein synthesis
Correct 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 57
Correct
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A 30 year old lawyer presented with a history of pleural effusions, pericarditis, arthralgia without joint deformity and episodes of myalgia for the past 12 months. Blood tests reveal a normocytic anaemia. Which of the following tests should be performed to investigate this condition further?
Your Answer: Antinuclear antibody test
Explanation:These non specific findings are suggestive of autoimmune disease. Antinuclear antibody (ANA) is the first test that should be performed when autoimmune diseases are suspected and later on more specific tests should be performed. This tests aids in the diagnosis of SLE, scleroderma, Sjogren’s syndrome, Raynaud’s disease, juvenile chronic arthritis, rheumatoid arthritis and antiphospholipid antibody syndrome etc. To confirm the disease a history, physical examination along with specific tests are required.
CPK is more specific for acute conditions.
ESR is a non specific test for inflammation.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 58
Correct
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Loperamide is a drug used to treat diarrhoea. What is the mechanism of action of loperamide?
Your Answer: Opiate agonist
Explanation:Loperamide is an opioid-receptor agonist and acts on the mu opioid receptors in the myenteric plexus of large intestine. It works by decreasing the motility of the circular and longitudinal smooth muscles of the intestinal wall. It is often used for this purpose in gastroenteritis, inflammatory bowel disease, and short bowel syndrome.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 59
Correct
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Point of entry of the vagal trunk into the abdomen:
Your Answer: Oesophageal hiatus
Explanation:The oesophageal hiatus is located in the muscular part of the diaphragm a T10 and is above, in front and a little to the left of the aortic hiatus. It transmits the oesophagus, the vagus nerves and some small oesophageal arteries.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 60
Correct
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The primary area involved in the pathology of Parkinson's disease is:
Your Answer: Substantia nigra
Explanation:Parkinson’s disease is a degenerative, movement disorder of the central nervous system, and is typically characterized by muscle rigidity, tremor and bradykinesia (in extreme cases, akinesia). Secondary symptoms include high-level cognitive dysfunction and subtle language problems.
Parkinson’s disease is also called ‘primary Parkinsonism’ or ‘idiopathic Parkinson’s disease and is the most common cause of Parkinsonism, a group of similar symptoms. The disorder is caused due to loss of pigmented dopaminergic cells in the pars compacta region of the substantia nigra.
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This question is part of the following fields:
- Neurology
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
