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Question 1
Correct
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Work of breathing (WOB) is the energy expended to inhale and exhale a breathing gas. Normally, maximal amount of work of breathing is required to overcome:
Your Answer: Elastic lung compliance
Explanation:The forces of elastance (compliance), frictional resistance and inertia have been identified as the forces that oppose lung inflation and deflation. The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work. Inhalation is an active process requiring work. About 60–66% of the total work performed by the respiratory muscles is used to overcome the elastic or compliance characteristics of the lung–chest cage, 30–35% is used to overcome frictional resistance and only 2–5% of the work is used for inertia.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 2
Correct
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Which nuclei of the posterior grey column of the spinal cord are likely affected in a patient who has lost the sensation of pain and temperature?
Your Answer: Substantia gelatinosa
Explanation:Substantia gelatinosa is one of the nuclei in the posterior grey column along side other posterior grey column nuclei like the nucleus dorsalis, nucleus proprius, and posteromarginal nucleus. These nuclei are a collection of cells in the posterior grey area found in throughout the spinal cord. The substantia gelatinosa receives direct input from the dorsal nerve roots (sensory), especially from thermoreceptors and nociceptors (receptors for temperature and pain).
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This question is part of the following fields:
- Anatomy
- Neurology
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Question 3
Incorrect
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A sexually active 21 year old man presents with the history of dysuria for the past 3 days. Urine culture confirmed Neisseria gonorrhoeae and smear showed abundant neutrophils. Which of the following mediators is responsible for causing diapedesis of the neutrophils to reach the site of infection?
Your Answer: Hageman factor
Correct Answer: Complement C5a
Explanation:C5a is part of the complement cascade and is released frim the complement C5. It acts as a chemotactic factor for neutrophils. Other chemotactic mediators are TNF, leukotrienes and bacterial products.
Bradykinin is associated with the production of pain and vasodilation.
Hageman factor is a clotting factor.
Histamine causes vasodilation.
C3B causes opsonisation.
IL-6 and IL-12 are inflammatory mediators causing B cell maturation and mediating inflammation and prostaglandins are involved with pain, increasing cell permeability and vasodilation.
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This question is part of the following fields:
- Inflammation & Immunology; Urology
- Pathology
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Question 4
Correct
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The specialist registrar, while performing the repair of an infrarenal abdominal aortic aneurysm, decides not to re-implant the inferior mesenteric artery into the repaired abdominal aorta. She says that an anastomotic artery running along the border of the large intestine is good enough to supply blood to the territory of the inferior mesenteric artery. Which vessel is she referring to?
Your Answer: Marginal
Explanation:The marginal artery is a key anastomosis for the large intestine that runs around the border of the large intestine and is formed by the anastomosis of the branches of the ileocolic artery, right colic artery, middle colic artery, left colic artery and sigmoid artery. If a small artery is occluded, these branches allow blood to reach all segments of the colon.
The arcades are anastomotic loops between the arteries that provide alternative pathways for blood flow. They are more prominent in the small intestine than the large intestine.
Arteriae rectae are small branches that run from the marginal artery to reach the colon.
The ileocolic artery is the branch of the superior mesenteric artery that supplies the caecum, appendix and terminal part of the ileum.
The coronary arteries supply blood to the heart.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 5
Correct
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A 44-year old man, who was euthyroid underwent thyroidectomy following neoplastic cells found on fine-needle aspiration. Frozen section of multiple thyroid masses showed malignant neoplasm of polygonal cells in nests. The neoplasm also showed presence of amyloid which was positive with Congo-red staining. Immunoperoxidase staining for calcitonin was also positive. Chest X-ray revealed no abnormality. However, his blood pressure was found to be raised, and his serum ionised calcium was high. What is the likely diagnosis?
Your Answer: Multiple endocrine neoplasia type IIA
Explanation:MEN (Multiple Endocrine Neoplasia) syndromes are a group of three separate familial disease which consists of adenomatous hyperplasia and neoplasia in several endocrine glands. All three conditions are inherited as an autosomal dominant trait, with a single gene producing multiple effects. MEN IIA is characterized by medullary carcinoma of the thyroid, pheochromocytoma and hyperparathyroidism. It should be suspected in patients with bilateral pheochromocytoma, a familial history of MEN, or at least two characteristic endocrine manifestations. Genetic testing is used to confirm the diagnosis. Early diagnosis is crucial to aid in complete excision of the localized tumour. Pheochromocytomas can be detected by plasma free metanephrines and fractionated urinary catecholamines, particularly adrenaline (epinephrine).
Imaging studies such as computed tomography or magnetic resonance imaging might also prove useful. Hyperparathyroidism is diagnosed by the standard finding of hypercalcaemia, hypophosphatemia and an increased parathyroid hormone level. Once MEN IIA syndrome is identified in any patient, it is recommended that his or her first-degree relatives and any other symptomatic also undergo genetic testing. Relatives should be subjected to annual screening for hyperparathyroidism and pheochromocytoma beginning in early childhood and continue indefinitely. Serum calcium levels help in screening for hyperparathyroidism. Similarly, screening for pheochromocytoma is by history, measurement of the blood pressure and laboratory testing.
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This question is part of the following fields:
- Endocrine
- Pathology
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Question 6
Incorrect
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Which of the following is a fact worth noting about the development of the spleen?
Your Answer: It develops in the ventral mesogastrium
Correct Answer: It develops in the dorsal mesogastrium
Explanation:The spleen in the human embryo arises in week 5 of intrauterine life. It appears as a proliferating mesenchyme above the pancreas. The spleen is one the organs that develops in the dorsal mesogastrium. When the stomach changes its position during development, the spleen is made to move behind the stomach and stays in contact with the left kidney. The spleen is found within the peritoneum of the abdominal cavity thus it is an intraperitoneal organ.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 7
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 8
Incorrect
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Which of the following veins empties into the left renal vein?
Your Answer: Left phrenic
Correct Answer: Left suprarenal
Explanation:The left suprarenal vein empties into the left renal vein which crosses the vertebral column to reach the inferior vena cava. The left renal vein also receives the left gonadal vein.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 9
Correct
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A 40-year old Caucasian male came to the hospital with complaints of fatigue and lethargy. On examination, he was found to have raised blood pressure. Urine examination showed >300 mg/dl proteinuria (4+) and 24-hour urine protein 3.5g. No glucose, blood, nitrites, urobilinogen or casts were present in urine. What is the most likely diagnosis?
Your Answer: Membranous glomerulonephritis
Explanation:Membranous glomerulonephritis or nephropathy, is a renal disorder with insidious course and usually affects people aged 30-50 years. 85% cases are primary (or idiopathic). The other 15% are secondary to autoimmune conditions like SLE, infections like malaria or hepatitis B, drugs like captopril and NSAIDs, or malignancies (particularly lung or colonic carcinoma). This disease is caused due to circulating immune complexes which are said to form by binding of antibodies to antigens in glomerular basement membrane. This antigens could be endogenous or derived from systemic circulation. This immune complex triggers the complement system, resulting in formation of membrane attack complex (MAC) on glomerular epithelial cells. This further results in release of proteases and oxidants which damage the capillaries making them ‘leaky’. Moreover, the epithelial cells also secrete a mediator to reduce nephron synthesis and distribution.
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This question is part of the following fields:
- Pathology
- Renal
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Question 10
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 11
Incorrect
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Which of the following is the most accurate test for the diagnosis of primary syphilis?
Your Answer: Microbiological culture
Correct Answer: Dark-field microscopy
Explanation:Primary syphilis is transmitted via sexual contact. Lesions on genitalia, called a chancre occur after an asymptomatic incubation period of 10-90 days (average 21 days) after exposure. This chancre is a typically solitary (can be multiple), firm, painless, ulceration over the skin at the point of exposure to spirochete, seen on penis, vagina or rectum. It heals spontaneously after 4-6 weeks. Local lymphadenopathy can be seen.
Diagnosis is made by microscopy of fluid from lesion using dark-field illumination, taking care to not confuse with other treponemal disease. Screening tests include rapid plasma regain (RPR) and Venereal Diseases Research Laboratory (VDRL) tests. False positives are known to occur with these tests and can be seen in viral infections like hepatitis, varicella, Epstein-Barr virus, tuberculosis, lymphoma, pregnancy and IV drug use. More specific tests should therefore be carried out in case these screening tests are positive.
The Treponema pallidum hemagglutination assay (TPHA) and the fluorescent treponemal antibody absorption (FTAABS) test are based on monoclonal antibodies and immunofluorescence and are more specific. However, they can too show false positives with other treponemal diseases like yaws or pinta. Other confirmatory tests include those based on enzyme-linked immunoassays.
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This question is part of the following fields:
- Pathology
- Urology
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Question 12
Correct
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A drug abuser developed an infection which spread from the dorsum of the hand to the medial side of the arm along the course of the large cutaneous vein. Which vein is involved?
Your Answer: Basilic
Explanation:The basilic vein is one of two veins found in the forearm, the other is the cephalic vein. These veins originate from the deep venous arch of the hand. The cephalic vein ascends along the lateral side of the forearm, and the basilic vein runs up the medial side of the forearm.
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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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Signals pass through neuromuscular junctions via the neurotransmitter acetylcholine. After release from the skeletal neuromuscular junction, acetylcholine:
Your Answer: Causes postsynaptic depolarisation
Explanation:Acetylcholine is released from the presynaptic membrane into the cleft where it binds to the ion gated channels on the post synaptic membrane, causing them to open. This results in sodium entering into the fibre and further depolarizing it, creating an action potential.
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This question is part of the following fields:
- General
- Physiology
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Question 14
Correct
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Which of the following structures lying posterior to the ovary are at risk of injury in excision of a malignant tumour in the right ovary?
Your Answer: Ureter
Explanation:The ovaries are two nodular structures situated one on either side of the uterus in relation to the lateral wall of the pelvis and attached to the back of the broad ligament of the uterus, lying posteroinferiorly to the fallopian tubes. Each ovary has a lateral and medial surface. The ureter is at greater risk of iatrogenic injury at this location.
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This question is part of the following fields:
- Anatomy
- Pelvis
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Question 15
Correct
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Rapid eye movement (REM) sleep is likely to be affected by a lesion in the:
Your Answer: Pons
Explanation:Rapid eye movement (REM) sleep is also known as paradoxical sleep, as the summed activity of the brain’s neurons is quite similar to that during waking hours. Characterised by rapid movements of the eyes, most of the vividly recalled dreams occur during this stage of sleep. The total time of REM sleep for an adult is about 90–120 min per night.
Certain neurones in the brainstem, known as REM sleep-on cells, which are located in the pontine tegmentum, are particularly active during REM sleep and are probably responsible for its occurrence. The eye movements associated with REM are generated by the pontine nucleus with projections to the superior colliculus and are associated with PGO (pons, geniculate, occipital) waves.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 16
Correct
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Which of the following organs is an ectoderm derivative?
Your Answer: Adrenal medulla
Explanation:Ectoderm derivatives include the adrenal medulla, posterior pituitary, the epidermis of the skin, nails, hair, sweat glands, mammary glands, sebaceous glands, the central nervous system, the peripheral nervous system, the retina and lens of eye, the pupillary muscle of the iris, melanocytes, Schwann cells and odontoblasts.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 17
Correct
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A 30-year-old female was alarmed when she started to experience hair loss and balding, however, she also noted increased hair on her face and body and developed an acne breakout. Deepening of her voice also became prominent. She was referred to an oncologist and was diagnosed with a hormone-producing tumour. What is the most likely diagnosis ?
Your Answer: Arrhenoblastoma
Explanation:Arrhenoblastoma, known as ‘Sertoli–Leydig tumour’ is a rare ovarian stromal neoplasm that secretes testosterone. It is mostly seen in women in the reproductive years. The key clinical features of this tumour is due to excessive production of testosterone which leads to progressive masculinisation in a woman who was typical normal beforehand. The lesion tends to grow slowly and rarely metastasises. Treatment is surgical removal of the tumour and the prognosis is generally good.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 18
Correct
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Which of the following clinical signs will be demonstrated in a case of Brown-Séquard syndrome due to hemisection of the spinal cord at mid-thoracic level?
Your Answer: Ipsilateral spastic paralysis, ipsilateral loss of vibration and proprioception (position sense) and contralateral loss of pain and temperature sensation beginning one or two segments below the lesion
Explanation:Brown–Séquard syndrome results due to lateral hemisection of the spinal cord and results in a loss of motricity (paralysis and ataxia) and sensation. The hemisection of the cord results in a lesion of each of the three main neural systems: the principal upper motor neurone pathway of the corticospinal tract, one or both dorsal columns and the spinothalamic tract. As a result of the injury to these three main brain pathways the patient will present with three lesions. The corticospinal lesion produces spastic paralysis on the same side of the body (the loss of moderation by the upper motor neurons). The lesion to fasciculus gracilis or fasciculus cuneatus results in ipsilateral loss of vibration and proprioception (position sense). The loss of the spinothalamic tract leads to pain and temperature sensation being lost from the contralateral side beginning one or two segments below the lesion. At the lesion site, all sensory modalities are lost on the same side, and an ipsilateral flaccid paralysis.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 19
Correct
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A swimmer was struggling to finish his training following an injury to his right arm. On further examination it was found that any movements involving adduction, medial rotation and extension of her arm were particularly weak. Which nerve in this case was damaged?
Your Answer: Thoracodorsal
Explanation:Weakness on these particular movements indicate that there is a problem with the latissimus dorsi muscle. This muscle is very important particularly in swimming movements and is supplied by the thoracodorsal nerve.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 20
Correct
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Which of the following muscles may be affected by a fracture to the tuberosity on the medial surface of the right navicular bone?
Your Answer: Tibialis posterior
Explanation:The navicular bone is situated at the medial side of the tarsus, between the talus and the cuneiform bones. Its medial surface presents a rounded tuberosity, the lower part of which gives attachment to part of the tendon of the tibialis posterior.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 21
Correct
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A 65 year old man with a history of diabetes and hypertension presented with a stroke a few months ago severely affecting his speech and movement in the right arm and leg. A cerebral angiogram revealed a middle cerebral artery occlusion. A recent CT scan was done which revealed a 5 cm cystic space in his left parietal lobe. This lesion is a result of which of the following forms of resolution?
Your Answer: Liquefactive necrosis
Explanation:Characteristically, the brain will undergo liquefactive necrosis following ischaemic injury. This leaves a cystic space in that region which would show up on a CT scan. Atrophy would result in a generalized decrease in the brain size. Coagulative necrosis typically occurs in parenchymal organs e.g. the spleen or kidney which have a lower lipid content. Caseous necrosis is typical in granulomatous tuberculosis infection. Apoptosis will not form a cystic area as it is programmed cell death involving a individual cells. Gangrenous necrosis is characteristic of ischaemic injury of the lower limb and GI tract. Fibrinous necrosis results from necrotic damage to the blood vessels with the leaking of proteins into the vessel, appearing bright pink on H & E staining.
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This question is part of the following fields:
- Cell Injury & Wound Healing; Neurology
- Pathology
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Question 22
Correct
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The mechanism of action of streptokinase involves:
Your Answer: Direct conversion of plasminogen to plasmin
Explanation:Streptokinase is an enzyme that is produced by group A beta haemolytic streptococcus and is an effective and cost efficient method for the dissolution of a clot used in cases of MI and pulmonary embolism. It works by directly converting plasminogen to plasmin which breaks down the blood components in the clot and fibrin, dissolving the clot. Streptokinase is a bacterial product and thus the body will develop immunity against it.
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This question is part of the following fields:
- General
- 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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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 25
Correct
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Which of the deep fasciae located in the anterolateral abdominal wall form the inguinal ligament?
Your Answer: External abdominal oblique aponeurosis
Explanation:The inguinal ligament is the inferior border of the aponeurosis of the external oblique abdominis and extends from the anterior superior iliac spine to the pubic tubercle from whence it is reflected backward and laterally to attach to the pectineal line and form the lacunar ligament.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 26
Correct
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To reach the oral vestibule, the parotid duct must pierce this muscle:
Your Answer: Buccinator muscle
Explanation:The parotid duct or Stensen duct is a duct and the route that saliva takes from the major salivary gland, the parotid gland into the mouth. The parotid duct is formed when several interlobular ducts—the largest ducts inside the parotid gland join. It emerges from the gland and runs forward along the lateral side of the masseter muscle. In this course, the duct is surrounded by the buccal fat pad. It takes a steep turn at the border of the masseter and passes through the buccinator muscle, opening into the vestibule of the mouth, between the cheek and the gums, at the parotid papilla, which lies across the second superior molar tooth.
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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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Which of the following morphological features is most characteristic of hyaline degeneration?
Your Answer: Pyknotic, densely stained nucleus
Correct Answer: Homogeneous, ground-glass, pink-staining appearance of cells
Explanation:The characteristic morphological features of hyaline degeneration is ground-glass, pinking staining cytoplasm with an intact cell membrane. The accumulation of lipids, calcium salts, lipofuscin and an amorphous cytoplasm with an intact cell membrane are all characteristically found in different situations.
Pyknotic nucleus and orphan Annie eye nucleus are not seen in hyaline degeneration.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 28
Incorrect
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Which of the following changes in the histology of the cell is most likely to be accompanied by disruption of the cell membrane following an injury?
Your Answer: Pyknosis
Correct Answer: Coagulative necrosis
Explanation:The process of necrosis ends with the rupture of the cell membrane and the consequent release of the cellular components into the surrounding tissue. Apoptosis, pyknosis and karyorrhexis are not reversible events but the cell membrane remains intact. Cloudy swelling and hydropic changes are also reversible but again the cell membrane remains intact and they are therefore different and distinct from necrosis.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 29
Correct
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A textbook of cardiac surgery explains that while doing a left pneumonectomy, a surgeon must be careful to avoid injury to a vital structure that leaves an impression on the mediastinal surface of the left lung. Which structure is it referring to?
Your Answer: Aortic arch
Explanation:Structures that leave an impression on the mediastinal surface of the left lung include: the oesophagus, subclavian artery, brachiocephalic vein, first rib, thymus, the heart, the diaphragm, descending aorta and arch of the aorta. The other structures form an impression on the mediastinal aspect of the right lung.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 30
Incorrect
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Which of the following malignancies is likely to have the best prognosis?
Your Answer: Anaplastic carcinoma of the thyroid
Correct Answer: Papillary carcinoma of the thyroid
Explanation:Papillary carcinoma accounts for 70-80% of all thyroid cancers and is seen commonly in people aged 30-60 years. It is more aggressive in elderly patients. 10-20% cases may have recurrence or persistent disease. More common in females with a female to male ratio of 3:1. Papillary carcinomas can also contain follicular carcinomas. The common route of spread is through lymphatics to regional nodes in one-third cases and pulmonary metastasis can also occur. Papillary carcinomas of the thyroid have the best prognosis, especially in patients less than 45 years of age with small tumours confined to the thyroid gland.
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This question is part of the following fields:
- Endocrine
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
