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Question 1
Incorrect
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Which of the following mediators of inflammation requires arachidonic acid for synthesis?
Your Answer: Tumour necrosis factor
Correct Answer: Prostaglandins
Explanation:Arachidonic acid is normally present in the phospholipids that make up the cell membrane and is cleaved by phospholipase A2 from the phospholipid. Arachidonic acid is a precursor for the production of eicosanoids which include: 1) prostaglandins, prostacyclins and thromboxane, 2) leukotrienes and 3) anandamides. The production of these products along with their action on the body is called the arachidonic acid cascade.
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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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Which of the following is a likely cause of jaundice?
Your Answer: Hepatic disease if plasma albumin is low and serum aminotransferase elevations > 500 units
Explanation:Jaundice can occur due to any of the possible causes and treatment depends upon diagnosing the correct condition. Mild hyperbilirubinemia with normal levels of aminotransferase and alkaline phosphatase is often unconjugated (e.g., due to haemolysis or Gilbert’s syndrome rather than hepatobiliary disease). Moderate or severe hyperbilirubinemia along with increased urinary bilirubin (bilirubinuria), high alkaline phosphatase or aminotransferase levels suggest hepatobiliary disease. Hyperbilirubinemia produced by any hepatobiliary disease is largely conjugated. In this case, other blood tests include hepatitis serology for suspected hepatitis, prothrombin time (PT) or international normalised ratio (INR), albumin and globulin levels, and antimitochondrial antibody levels (suspected primary biliary cirrhosis). Low albumin and high globulin levels suggest chronic rather than acute liver disease. In cases where there is only a an elevation of alkaline phosphatase, γ-glutamyl transpeptidase (GGT) levels should be checked – the levels of which will be found high in hepatobiliary disease, but not in bone disorder which can also lead to elevated alkaline phosphatase levels. In diseases of hepatobiliary origin, aminotransferase elevations > 500 units suggest a hepatocellular cause, whereas disproportionate increases of alkaline phosphatase (e.g., alkaline phosphatase > 3 times normal and aminotransferase < 200 units) suggest cholestasis. Because hepatobiliary disease alone rarely causes bilirubin levels > 30 mg/dl, higher levels are suggestive of a combination of severe hepatobiliary disease and haemolysis or renal dysfunction. Imaging is best for diagnosing infiltrative and cholestatic causes of jaundice. Liver biopsy is rarely needed, but can be of use in intrahepatic cholestasis and in some types of hepatitis.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 3
Incorrect
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Which is the correct order of tendons passing from medial to lateral-posterior to the medial malleolus?
Your Answer: Flexor hallucis longus, flexor digitorum longus, posterior tibial
Correct Answer: Posterior tibial, flexor digitorum longus, flexor hallucis longus
Explanation:The correct order of structures is the tendon of tibialis posterior, tendon of flexor digitorum longus, posterior tibial artery (and vein), tibial nerve and tendon of flexor hallucis longus.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 4
Incorrect
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A 62-year-old woman presented to the doctor complaining of spine pain, fatigue and oliguria. She is diagnosed with chronic renal failure. Dipstick testing shows no protein, glucose, nitrite or ketones but a semi-quantitative sulphosalicylic acid test for urine protein is positive. Which of the following is the most probable cause of chronic renal failure in this patient.
Your Answer: Membranous glomerulonephritis
Correct Answer: Multiple myeloma
Explanation:Dipstick results are negative because the proteins found in the urine of this patient are not albumin but Bence Jones proteins. A Bence Jones protein is a monoclonal globulin protein commonly detected in patients affected by multiple myeloma. Multiple myeloma is a malignancy of plasma cells characterised by the production of monoclonal immunoglobulin. Symptoms include bone pain, bone fractures, bleeding, neurologic symptoms, fatigue, frequent infections and weight loss.
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This question is part of the following fields:
- Pathology
- Renal
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Question 5
Correct
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A 45 year-old female presents with a drooping eyelid. During examination, the same pupil of the patient is found to be dilated. Which nerve could be involve in this case?
Your Answer: Oculomotor nerve
Explanation:The oculomotor nerve controls most of the eye muscles. It also controls the constriction of the pupils and thickening of the lens of the eye. This can be tested in two main ways. By moving a finger toward a person’s face to induce accommodation, their pupils should constrict or shining a light into one eye should result in equal constriction of the other eye. The neurons in the optic nerve decussate in the optic chiasm with some crossing to the contralateral optic nerve tract. This is the basis of the swinging-flashlight test. Loss of accommodation and continued pupillary dilation can indicate the presence of a lesion of the oculomotor nerve.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 6
Correct
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Chronic obstructive pulmonary disease (COPD) is likely to result in:
Your Answer: Respiratory acidosis
Explanation:COPD leads to respiratory acidosis (chronic). This occurs due to hypoventilation which involves multiple causes, such as poor responsiveness to hypoxia and hypercapnia, increased ventilation/perfusion mismatch leading to increased dead space ventilation and decreased diaphragm function.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 7
Correct
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What is the likely course of a pulmonary embolism arising from the leg veins and ending in the apical segmental pulmonary artery that supplies the superior lobe of left lung?.
Your Answer: Inferior vena cava – right atrium – tricuspid valve – right ventricle – pulmonary trunk – left pulmonary artery – left superior lobar artery – left apical segmental artery
Explanation:A clot originating in the leg vein will go to the inferior vena cava, into the right atrium, through the tricuspid valve, into the right ventricle, through the pulmonary trunk, into the left pulmonary artery, into the left superior lobar artery and then finally reach the left apical segmental artery.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 8
Incorrect
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Multiple cells were labelled using a fluorescent dye that doesn’t cross the cell membrane. One cell in the middle was bleached with a light that destroys the dye, but the cell soon recovers its stain. The presence of which structures best explains this?
Your Answer:
Correct Answer: Gap junctions
Explanation:Gap junctions are attachments between cells that permit intercellular communication e.g. they permit current flow and electrical coupling between myocardial cells. They allow direct electrical transmission among cells and also permit certain substance to pass through as well. They are either homotypic, formed by two identical hemichannels or heterotypic, formed by different hemichannels.
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This question is part of the following fields:
- General
- Physiology
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Question 9
Incorrect
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Which of the following is responsible for the maximum increase in total peripheral resistance on sympathetic stimulation?
Your Answer:
Correct Answer: Arterioles
Explanation:Arterioles are also known as the resistance vessels as they are responsible for approximately half the resistance of the entire systemic circulation. They are richly innervated by the autonomic nervous system and hence, will bring about the maximum increase in peripheral resistance on sympathetic stimulation.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 10
Incorrect
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From which source does the lingual artery originate?
Your Answer:
Correct 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 11
Incorrect
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A 65-year-old man complains of headaches, weakness, cramps, and confusion; blood tests reveal he has severe hyponatremia. The most likely cause is:
Your Answer:
Correct Answer: Severe diarrhoea or vomiting
Explanation:Hyponatraemia occurs when the sodium level in the plasma falls below 135 mmol/l. Hyponatraemia is an abnormality that can occur in isolation or, more commonly as a complication of other medical illnesses. Severe hyponatraemia may cause osmotic shift of water from the plasma into the brain cells. Typical symptoms include nausea, vomiting, headache and malaise. As the hyponatraemia worsens, confusion, diminished reflexes, convulsions, stupor or coma may occur. The cause of hyponatremia is typically classified by a person’s fluid status into low volume, normal volume, and high volume. Low volume hyponatremia can occur from diarrhoea, vomiting, diuretics, and sweating.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 12
Incorrect
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A 28-year old lady comes to the surgical clinic with a recently detected lump in her right breast. On examination, the lump is found to be 1cm, rubbery, mobile with no palpable axillary nodes. Mammography reveals no microcalcifications and the opposite breast appears normal. What is the likely diagnosis?
Your Answer:
Correct Answer: Fibroadenoma
Explanation:A benign breast tumour, fibroadenoma is common below the age of 30 years and occurs due to oestrogenic excess. It is characterised by proliferation of both glandular and stromal elements. Fibroadenomas are usually solitary and are mobile, not fixed to surrounding structures. The tumour is elastic, nodular and encapsulated with a grey-white cut surface. The two main histological types include intracanalicular and pericanalicular types, with both types often present in the same tumour. In the intracanalicular type, the stromal proliferation component predominates causing compression of ducts making them appear slit-like. In pericanalicular type, the fibrous stroma dominates around the ductal spaces so that they remain oval on cross section.
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This question is part of the following fields:
- Pathology
- Women's Health
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Question 13
Incorrect
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A 25-year old man presented to the clinic with swelling of the penis. His uncircumcised penis was erythematous and oedematous. The foreskin could not be retracted over the glans. Which of the following agents is the likely cause of his condition?
Your Answer:
Correct Answer: Staphylococcus aureus
Explanation:Inflammation of the glans penis is known as balanitis. Associated involvement of the foreskin is then known as balanoposthitis. More likely to occur in men who have a tight foreskin that is difficult to pull back, or poor hygiene.
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This question is part of the following fields:
- Pathology
- Urology
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Question 14
Incorrect
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Calculate the resistance of the artery if the pressure at one end is 60 mmHg, pressure at the other end is 20 mm Hg and the flow rate in the artery is 200 ml/min.
Your Answer:
Correct Answer: 0.2
Explanation:Flow in any vessel = Effective perfusion pressure divided by resistance, where effective perfusion pressure is the mean intraluminal pressure at the arterial end minus the mean pressure at the venous end. Thus, in the given problem, resistance = (60 − 20)/200 = 0.2 mmHg/ml per min.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 15
Incorrect
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In relation to the muscles of facial expression, It is true to say:
Your Answer:
Correct Answer: They are in the same subcutaneous plane as the platysma muscle
Explanation:The facial muscles generally originate from the facial bones and attach to the skin, in the same plane as the platysma muscle. They are all innervated by cranial nerve VII (the facial nerve). The occipitofrontalis muscle consists of two parts: The occipital belly, near the occipital bone, and the frontal belly, near the frontal bone.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 16
Incorrect
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In a young, sexually active male, what is the most common cause of non-gonococcal urethritis?
Your Answer:
Correct Answer: Chlamydia
Explanation:Non-gonococcal urethritis is most commonly caused by Chlamydia trachomatis (50% cases). Less common organisms include Mycoplasma genitalium, Urea urealyticum and Trichomonas vaginalis. Chlamydia is also the commonest cause of non-gonococcal cervicitis in women and proctitis in both sexes.
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This question is part of the following fields:
- Pathology
- Renal
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Question 17
Incorrect
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A 39-year-old man, after radiological evaluation and thoracentesis, was found to have chylothorax. What is the most probable cause of this diagnose?
Your Answer:
Correct Answer: Mediastinal malignant lymphoma
Explanation:Chylothorax is a potentially lethal condition characterized by fluid (chyle) accumulation in the pleural cavity, resulting from disruption of lymphatic drainage in the thoracic duct. Chyle is a fluid rich in triglycerides and chylomicrons and can originate from the thorax, the abdomen or both. Malignant tumours, especially lymphoma, are the most common causes of nontraumatic chylothorax. Bronchogenic carcinoma and trauma are the most common causes after lymphomas. Other rare causes of chylothorax are; granulomatous diseases, tuberculosis, congenital malformations, nephrotic syndrome, hypothyroidism, cirrhosis, decompensated heart failure and idiopathic chylothorax.
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This question is part of the following fields:
- Pathology
- Respiratory
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Question 18
Incorrect
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Mechanical distortion, and not K+ channels are responsible for distortion of which of the following structures?
Your Answer:
Correct Answer: Pacinian corpuscle
Explanation:Pacinian corpuscles are a type of mechanoreceptor, sensitive to deep pressure, touch and high-frequency vibration. The Pacinian corpuscles are ovoid and about 1 mm long. In the centre of the corpuscle is the inner bulb, which is a fluid-filled cavity with a single afferent unmyelinated nerve ending. Any deformation in the corpuscle causes the generation of action potentials by opening of pressure-sensitive sodium ion channels in the axon membrane. This allows influx of sodium ions, creating a receptor potential (independent of potassium channels).
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This question is part of the following fields:
- Neurology
- Physiology
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Question 19
Incorrect
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As per the Poiseuille-Hagen formula, doubling the diameter of a vessel will change the resistance of the vessel from 16 peripheral resistance units (PRU) to:
Your Answer:
Correct Answer: 1 PRU
Explanation:Poiseuille-Hagen formula for flow in along narrow tube states that F = (PA– PB) × (Π/8) × (1/η) × (r4/l) where F = flow, PA– PB = pressure difference between the two ends of the tube, η = viscosity, r = radius of tube and L = length of tube. Also, flow is given by pressure difference divided by resistance. Hence, R = 8ηL ÷ Πr4. Hence, the resistance of the vessel changes in inverse proportion to the fourth power of the diameter. So, if the diameter of the vessel is increased to twice the original, it will lead to decrease in resistance to one-sixteenth its initial value.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 20
Incorrect
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Purkinje fibres in the heart conduct action potentials at the rate of:
Your Answer:
Correct Answer: 1.5–4.0 m/s
Explanation:Purkinje fibres control the heart rate along with the sinoatrial node (SA node) and the atrioventricular node (AV node). The QRS complex is associated with the impulse passing through the Purkinje fibres. These fibres conduct action potential about six times faster than the velocity in normal cardiac muscle.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 21
Incorrect
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A week after a renal transplant the patient received antilymphocyte globulins. Shortly after she developed fever and hypotension. Which of the following mechanisms is involved in this response?
Your Answer:
Correct Answer: Type III hypersensitivity
Explanation:Type III hypersensitivity is characterized by soluble immune complexes which are aggregations of IgG and IgM antibodies with antigens that deposit in different tissues e.g. the skin, joints, kidneys. They can then trigger an immune response by activating the complement cascade. This reaction can take hours to develop and examples include: immuno-complex glomerulonephritis, rheumatoid arthritis, SLE, subacute bacterial endocarditis, arthus reaction and serum sickness.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 22
Incorrect
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A 70-year old man who is suspected to have a perforated colonic diverticulum is explored in theatre through a midline incision. This incision will be through the:
Your Answer:
Correct Answer: Linea alba
Explanation:The linea alba is the point where this incision was made. It is a tendinous raphe in the midline of the abdomen extending between the xiphoid process and the symphysis pubis. It is placed between the medial borders of the recti and is formed by the blending of the aponeuroses of the external and internal obliques and transversi.
The linea aspera is a vertical ridge on the posterior surface of the femur.
The arcuate line is the inferior border of the posterior rectus sheath behind the rectus abdominis muscle.
The semilunar line is the lateral margin of the rectus abdominis.
The iliopectineal line is a line on the pelvic bones formed by the arcuate line of the ilium and the pectineal line of the pubis.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 23
Incorrect
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Epstein-Barr virus (EBV) is known to be a carcinogen for:
Your Answer:
Correct Answer: B-cell lymphoma
Explanation:EBV is known to be carcinogenic for B-cell lymphoma, nasopharyngel carcinoma and Hodgkin’s lymphoma.
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This question is part of the following fields:
- Microbiology; Neoplasia
- Pathology
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Question 24
Incorrect
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A 70-year-old male who has smoked since his teens complains of progressive shortness of breath and a persistent cough. He is diagnosed with COPD. Which of the following abnormalities is most likely to be present in his pulmonary function tests?
Your Answer:
Correct Answer: Increased residual volume
Explanation:Chronic obstructive pulmonary disease (COPD) is a type of obstructive lung disease characterized by long-term poor airflow. The main symptoms include shortness of breath and cough with sputum production. The best diagnostic test for evaluating patients with suspected chronic obstructive pulmonary disease (COPD) is lung function measured with spirometry. Key spirometrical measures may be obtained with a portable office spirometer and should include forced vital capacity (FVC) and the normal forced expiratory volume in the first second of expiration (FEV1). The ratio of FEV1 to forced vital capacity (FEV1/FVC) normally exceeds 0.75. Patients with COPD typically present with obstructive airflow. Complete pulmonary function testing may show increased total lung capacity, functional residual capacity and residual volume. A substantial loss of lung surface area available for effective oxygen exchange causes diminished carbon monoxide diffusion in the lung (DLco) in patients with emphysema. Tobacco smoking is the most common cause of COPD, with factors such as air pollution and genetics playing a smaller role.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 25
Incorrect
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A elderly patient with bulbar palsy is bed ridden. While swallowing he aspirates one of his tablets into his lungs. In which bronchopulmonary segments is it most likely to end up?
Your Answer:
Correct Answer: Superior segmental bronchus of the right inferior lobe
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 superior segmental bronchus branches posteriorly off the intermediate bronchus or the inferior lobe bronchus and is thus more likely to receive the foreign body that enters the right main bronchus. The lingula is only found on the left lung. The terminal bronchiole is a very small space almost impossible for the tablet to lodge here.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 26
Incorrect
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Injury to this nerve will affect the function of the palatoglossus and levator veli palatini muscles:
Your Answer:
Correct Answer: Cranial nerve X
Explanation:The vagus nerve (cranial nerve X) innervates both the palatoglossus and levator veli palatini muscles.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 27
Incorrect
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Infection to all of the following will lead to enlargement of the superficial inguinal lymph nodes, except for:
Your Answer:
Correct Answer: Ampulla of the rectum
Explanation:The superficial inguinal lymph nodes form a chain immediately below the inguinal ligament. They receive lymphatic supply from the skin of the penis, scrotum, perineum, buttock and abdominal wall below the level of the umbilicus.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 28
Incorrect
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A patient is diagnosed with a tumour of the parotid gland. During surgical removal of the gland, which artery is vulnerable to injury?
Your Answer:
Correct Answer: External carotid artery
Explanation:The external carotid artery is a major artery of the head and neck. It arises from the common carotid artery when it splits into the external and internal carotid artery. It supplies blood to the face and neck. The external carotid artery begins opposite the upper border of the thyroid cartilage and, taking a slightly curved course, passes upward and forward and then inclines backward to the space behind the neck of the mandible, where it divides into the superficial temporal and internal maxillary arteries. It rapidly diminishes in size in its course up the neck, owing to the number and large size of the branches given off from it. At its origin, this artery is more superficial and placed nearer the midline than the internal carotid and is contained within the carotid triangle. The external carotid artery is covered by the skin, superficial fascia, platysma, deep fascia and anterior margin of the sternocleidomastoid. It is crossed by the hypoglossal nerve, by the lingual, ranine, common facial and superior thyroid veins; and by the digastric and stylohyoid; higher up it passes deeply into the substance of the parotid gland, where it lies deep to the facial nerve and the junction of the temporal and internal maxillary veins. It is here that it is in danger during surgery of the parotid gland.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 29
Incorrect
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A 46-year old lady presents with chief complaints of a large mass in the left breast. Histopathology of the mass revealed a stromal component with an epithelial component. What is the likely lesion?
Your Answer:
Correct Answer: Phyllodes tumour
Explanation:Phyllodes tumours are large, quickly growing tumours which arise from the periductal stroma of the breast. These are fibroepithelial tumours and account for less than 1% of breast cancers. These tumours can be benign, borderline or malignant based on the histology. The tumour usually affects adult women, mostly between the age of 40 to 50 years. It can be confused with fibroadenoma, which however affects much younger patients.
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This question is part of the following fields:
- Pathology
- Women's Health
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Question 30
Incorrect
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The primary somatosensory cortex is located in the:
Your Answer:
Correct Answer: Postcentral gyrus
Explanation:The primary somatic sensory cortex is located in the postcentral gyrus and is the largest cortical receiving area for information from somatosensory receptors. Through corticocortical fibres, it then sends the information to other areas of the neocortex and further analysis takes place in the posterior parietal association cortex.
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This question is part of the following fields:
- Neurology
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
