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Question 1
Incorrect
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Urine specific gravity allows the assessment of which of the following renal functions?
Your Answer: Filtration
Correct Answer: Concentration
Explanation:Concentrating ability of kidneys is assessed by measuring the urine specific gravity. Normal values of urine specific gravity fall between 1.002 and 1.030 g/ml.
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This question is part of the following fields:
- Pathology
- Renal
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Question 2
Correct
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A 26-year-old female patient had the following blood report: RBC count = 4. 0 × 106/μl, haematocrit = 27% and haemoglobin = 11 g/dl, mean corpuscular volume (MCV) = 90 fl, mean corpuscular haemoglobin concentration (MCHC) = 41 g/dl. Further examination of blood sample revealed increased osmotic fragility of the erythrocytes. Which of the following is the most likely cause of this patient’s findings?
Your Answer: Spherocytosis
Explanation:Spherocytes are small rounded RBCs. It is due to an inherited defect of the RBC cytoskeleton membrane tethering proteins. Membrane blebs form that are lost over time and cells become round instead of biconcave. As it is a normochromic anaemia, the MCV is normal. it is diagnosed by osmotic fragility test which reveals increased fragility in a hypotonic solution.
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This question is part of the following fields:
- General
- Physiology
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Question 3
Correct
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A 51-year old woman after undergoing a barium swallowing was discovered to be suffering from an oesophageal hiatal hernia. Which muscle fibres of the diaphragm border this hernia directly if the stomach herniates through an enlarged oesophageal hiatus?
Your Answer: Right crus
Explanation:The oesophageal hiatus is a natural fissure on the thoracic diaphragm that allows passage of the oesophagus and the vagal nerve. The oesophageal hiatus is located in one of the tendinous structures of the diaphragm that connect it to the spine which is known as the right crus. In case of an hiatal hernia, this diaphragmatic structure would be the one bordering the hernia as it is the structure that encircles the oesophageal hiatus.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 4
Incorrect
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A cyclist fell and sustained a laceration to his elbow which was shortly sutured in the emergency department. Which of the following factors will aid in the wound healing process?
Your Answer: Corticosteroid therapy
Correct Answer: Presence of sutures
Explanation:Foreign bodies including sutures will delay wound healing, however due to the net affect being helpful they are used. Secondary wound infection will delay healing and is a potential post op complication. Corticosteroids depresses the wound healing ability of the body. Poor nutrition will also delay healing leading to decreased albumin, vit D and vit C. Diabetic patients with atherosclerosis with poor perfusion of tissues have notoriously delayed/poor healing.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 5
Incorrect
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Which antibiotic acts by inhibiting protein synthesis?
Your Answer: Co-trimoxazole
Correct Answer: Erythromycin
Explanation:Penicillins and cephalosporins (e.g. cefuroxime, cefotaxime, ceftriaxone) inhibit bacterial cell wall synthesis through the inhibition of peptidoglycan cross-linking.
Macrolides (e.g. erythromycin), tetracyclines, aminoglycosides and chloramphenicol act by interfering with bacterial protein synthesis.
Sulphonamides (e.g. trimethoprim, co-trimoxazole) work by inhibiting the synthesis of nucleic acid
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This question is part of the following fields:
- Pharmacology; Microbiology
- Physiology
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Question 6
Correct
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An episiotomy is indicated for a woman during a difficult vaginal delivery. Whilst the registrar was performing this procedure she made a median cut too far through the perineal body cutting the structure immediately posterior. Which structure is this?
Your Answer: External anal sphincter
Explanation:An episiotomy is an incision that is made whenever there is a risk of a tear during vaginal deliver. A posterolateral incision, as opposed to a median incision is preferred. Of the options given, the external anal sphincter lies right posterior to the perineal body. The sacrospinous and the sacrotuberous ligaments are deep in the perineum that they should not be involved in this.
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This question is part of the following fields:
- Anatomy
- Pelvis
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Question 7
Correct
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During an exploratory laparotomy of an acute abdomen, the surgeon identified an inflamed Meckel's diverticulum. This is:
Your Answer: Is a site of ectopic pancreatic tissue
Explanation:Meckel’s diverticulum is an outpouching of the small intestine. It usually occurs about 0.6 m (2 feet) before the junction with the caecum. It can be lined with the mucosa of the stomach and may ulcerate. It may also be lined by ectopic pancreatic tissue. It represents the remains of the vitelline duct in early fetal life.
An abnormal persistence of the urachus is called a urachal fistula.
Failure of the midgut loop to return to the abdominal cavity is called an omphalocele.
Polyhydramnios is often caused by anencephaly or oesophageal fistula.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 8
Correct
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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: 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 9
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 10
Correct
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Muscles and tendons in the planter region of the foot mainly take blood supply from:
Your Answer: Posterior tibial artery
Explanation:The posterior tibial artery is the main source of blood supply to the posterior compartment of the leg.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 11
Correct
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Which of the following is involved in vitamin B12 absorption?
Your Answer: Intrinsic factor
Explanation:Absorption of vitamin B12 is by an active transport process and occurs in the ileum. Most cobalamins are bound to proteins and are released in the stomach due to low pH and pepsin. The cobalamins then bind to R proteins, i.e. haptocorrin (HC) secreted from salivary glands and gastric juice. Another cobalamin binding protein is Intrinsic factor (IF) secreted from the gastric parietal cells. The cobalamin-HC complex is digested by pancreatic proteases in the intestinal lumen, and the free cobalamin then binds to IF. The complex then reaches a transmembrane receptor in the ileum and undergoes endocytosis. Cobalamin is then released intracellularly and binds to transcobalamin II (TC II). The newly formed complex then exits the ileal cell and enters the blood circulation.
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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 45 year old women has a 4 cm non tender mass in her right breast which is fixed to the chest wall. Another 2cm non-tender mass is palpable in the left axilla. Chest x ray reveals multiple nodules ranging from 0.5 - 0.2 cm in both the lungs. What is the stage of her disease?
Your Answer: T4 N1 M1
Explanation:This woman has an invasive primary tumour mass with axillary node and lung metastases, making this stage T4 N1 M1. Looking at the other stems, T1 N1 M0 signifies a small primary cancer with nodal metastases but no distant metastases; T1 N0 M1 signifies a small primary cancer with no lymph node metastases but with distant metastases; T2 N1 M0 signifies a larger primary cancer with nodal metastases but no distant metastases; and T3 N0 M0 indicates a larger primary cancer with no metastases to either lymph nodes or to distant sites.
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This question is part of the following fields:
- Neoplasia; Female Health
- Pathology
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Question 13
Correct
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Injury to this nerve may result in loss of sensation of the mandibular teeth and bone:
Your Answer: Inferior alveolar nerve
Explanation:The inferior alveolar nerve (sometimes called the inferior dental nerve) is a branch of the mandibular nerve, which is itself the third branch of the trigeminal nerve. The inferior alveolar nerves supply sensation to the lower teeth of the mandible.
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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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Which of the following toxins most likely results in continuous cAMP production, which pumps H2O, sodium, potassium, chloride and bicarbonate into the lumen of the small intestine and results in rapid dehydration?
Your Answer: Cholera toxin
Explanation:The cholera toxin (CTX or CT) is an oligomeric complex made up of six protein subunits: a single copy of the A subunit (part A), and five copies of the B subunit (part B), connected by a disulphide bond. The five B subunits form a five-membered ring that binds to GM1 gangliosides on the surface of the intestinal epithelium cells. The A1 portion of the A subunit is an enzyme that ADP-ribosylates G proteins, while the A2 chain fits into the central pore of the B subunit ring. Upon binding, the complex is taken into the cell via receptor-mediated endocytosis. Once inside the cell, the disulphide bond is reduced, and the A1 subunit is freed to bind with a human partner protein called ADP-ribosylation factor 6 (Arf6). Binding exposes its active site, allowing it to permanently ribosylate the Gs alpha subunit of the heterotrimeric G protein. This results in constitutive cAMP production, which in turn leads to secretion of H2O, Na+, K+, Cl−, and HCO3− into the lumen of the small intestine and rapid dehydration. The gene encoding the cholera toxin was introduced into V. cholerae by horizontal gene transfer.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 15
Correct
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A nerve is injured during a surgical operation to repair an inguinal hernia. It passes through the superficial inguinal ring. Which nerve is it most likely to be?
Your Answer: Ilioinguinal
Explanation:The ilioinguinal nerve doesn’t pass through the deep inguinal ring but enters the inguinal canal from the side and leaves by passing through the superficial ring thus it is at risk of injury during inguinal hernia repair.
The femoral branch of genitofemoral nerve travels lateral to the superficial inguinal ring.
The iliohypogastric nerve and the subcostal nerve travel superior to the inguinal canal and superficial inguinal ring.
The obturator nerve is a branch of the lumbar plexus that innervates the muscles of the thigh.
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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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A 40-year-old woman is suspected to have an ovarian cancer. Which tumour marker should be requested to confirm the diagnosis?
Your Answer: CA-125
Explanation:CA-125 is a protein that is used as a tumour marker. This substance is found in high concentration in patients with ovarian cancer. It is the only tumour marker recommended for clinical use in the diagnosis and management of ovarian cancer.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 17
Correct
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A 76-year-old man with a urinary tract obstruction due to prostatic hyperplasia develops acute renal failure. Which of the following physiological abnormalities of acute renal failure will be most life threatening for this patient?
Your Answer: Acidosis
Explanation:Acute renal failure (ARF) is a rapid loss of renal function due to damage to the kidneys, resulting in retention of nitrogenous (urea and creatinine) and non-nitrogenous waste products that are normally excreted by the kidney. This accumulation may be accompanied by metabolic disturbances, such as metabolic acidosis and hyperkalaemia, changes in body fluid balance and effects on many other organ systems. Metabolic acidosis and hyperkalaemia are the two most serious biochemical manifestations of acute renal failure and may require medical treatment with sodium bicarbonate administration and antihyperkalaemic measures. If not appropriately treated these can be life-threatening. ARF is diagnosed on the basis of characteristic laboratory findings, such as elevated blood urea nitrogen and creatinine, or inability of the kidneys to produce sufficient amounts of urine.
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This question is part of the following fields:
- Physiology
- Renal
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Question 18
Incorrect
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A young female in the 15th week of pregnancy presented to the emergency department with the passage of grape-like masses per vagina. Dilatation and curettage was done and microscopy revealed large avascular villi with trophoblastic proliferation. Which one of the following investigations is best recommended for her follow-up?
Your Answer: Endometrial biopsy
Correct Answer: Serum β-hCG
Explanation:Trophoblast is the layer of cells surrounding the blastocyst and that later develops into the chorion and amnion. Gestational trophoblastic disease is a tumour arising from this trophoblast. It can occur during or after either an intrauterine or ectopic pregnancy. If it occurs in a pregnant woman, it usually leads to spontaneous abortion, eclampsia or fetal death. It can be either malignant or benign.
In suspected cases, investigations include measurement of serum beta subunit of human chorionic gonadotrophin (β-hCG) and pelvic ultrasound. Confirmatory test is a biopsy. Post-removal, the disease is classified clinically to assess further treatment. To assess the presence of metastases, further work-up includes computed tomography of the brain, chest, abdomen and pelvis. Chemotherapy is usually needed for persistent disease. If at least three consecutive, weekly serum β-hCG measurements are normal, treatment is considered successful. Follow-up is also done by measuring β-hCG.
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This question is part of the following fields:
- Pathology
- Women's Health
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Question 19
Incorrect
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Regarding innervation to the peroneus brevis muscle:
Your Answer: Is by the same distal nerve that innervates the peroneus tertius muscle
Correct Answer: Could be damaged by a fracture of the neck of the fibula
Explanation:The peroneus brevis is supplied by the fourth and fifth lumbar and first sacral nerves through the superficial peroneal nerve which is one of the two terminal branches of the common peroneal nerve. The common peroneal nerve winds around the neck of the fibula and can be injured in cases of fractured neck of fibula.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 20
Correct
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An ECG of a 30 year old woman revealed low voltage QRS complexes. This patient is most probably suffering from?
Your Answer: Pericardial effusion
Explanation:The QRS complex is associated with current that results in the contraction of both the ventricles. As ventricles have more muscle mass than the atria, they result in a greater deflection on the ECG. The normal duration of a QRS complex is 10s. A wide and deep Q wave depicts myocardial infarction. Abnormalities in the QRS complex maybe indicative of a bundle block, ventricular tachycardia or hypertrophy of the ventricles. Low voltage QRS complexes are characteristic of pericarditis or a pericardial effusion.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 21
Correct
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Which of the following arteries, that runs on the superior aspect of the first part of the duodenum, forms the lower boundary of the epiploic foramen (also known as the foramen of Winslow)?
Your Answer: Hepatic
Explanation:The epiploic foramen is an important anatomical opening that allows for the communication between the greater peritoneal sac and the lesser peritoneal sac. Its boundaries are formed; superiorly by the caudate lobe of the liver, anteriorly by the hepatoduodenal ligament (containing the components of the portal triad), inferiorly by the first part of the duodenum and posteriorly by the peritoneum covering the inferior vena cava. The superior aspect of the first part of the duodenum, which forms the inferior boundary of the foramen of Winslow, forms the course of the hepatic artery before it ascends to the porta hepatis where it divides into its right and left branches.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 22
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 23
Correct
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The pterygoid plexus receives tributaries from which of the following veins?
Your Answer: Maxillary vein
Explanation:The pterygoid plexus of veins is the main venous component associated with the infratemporal fossa. It receives tributaries corresponding to the branches of the internal maxillary artery. This plexus communicates freely with the anterior facial vein; it also communicates with the cavernous sinus, by branches through the foramen of Vesalius, foramen ovale and foramen lacerum. The (internal) maxillary vein is a short trunk which accompanies the first part of the (internal) maxillary artery. It is formed by a confluence of the veins of the pterygoid plexus and passes backward between the sphenomandibular ligament and the neck of the mandible and unites with the temporal vein to form the posterior facial vein. It carries blood away from the infratemporal fossa.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 24
Correct
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A cerebellar tremor can be differentiated from a Parkinsonian tremor in that:
Your Answer: It only occurs during voluntary movements
Explanation:Cerebellar disease leads to intention tremors, which is absent at rest and appears at the onset of voluntary movements. In comparison, Parkinson’s tremor is present at rest. Frequency of tremor is a less reliable means to differentiate between the two as the oscillation amplitude of the tremor is not constant throughout a voluntary action.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 25
Correct
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The gastrosplenic ligament also known as the gastrolienal ligament is the structure that connects the greater curvature of the stomach to the hilum of the spleen. Which of the following arteries would most likely be injured if a surgeon accidentally tore this ligament?
Your Answer: Short gastric
Explanation:The short gastric arteries arise from the end of the splenic arteries and form five to seven branches. The short gastric arteries inside the gastrosplenic ligament from the left to the right, supply the greater curvature of the stomach. The hepatic artery proper runs inside the hepatoduodenal ligament. The right gastric artery and the left gastric artery are contained in the hepatogastric ligament. The caudal pancreatic artery branches off from the splenic artery and supplies the tail of the pancreas. The middle colic artery supplies the transverse colon. The splenic artery does not travel in the gastrosplenic ligament and so it would not be damaged by a tear to this ligament.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 26
Correct
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On exploration of an axillary wound, a branch from the third part of the axillary artery was found to be transected. Which of the following arteries would have been likely injured?
Your Answer: Anterior circumflex humeral
Explanation:The axillary artery gives off many branches from the first, second, or third parts along its course. The third part of the axillary artery gives off 3 branches: the subscapular, anterior and posterior circumflex humeral arteries.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 27
Correct
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Which of the following substances will enhance the activity of antithrombin III?
Your Answer: Heparin
Explanation:Antithrombin III is a glycoprotein that inactivates multiple enzymes involved in the coagulation system. It inactivates factor X, factor IX, factor II, factor VII, factor XI and factor XII. Its activity is greatly increased by the action of heparin.
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This question is part of the following fields:
- General
- Physiology
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Question 28
Correct
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A 24-year old, lactating mother presents to the clinic with a tender, 1.5cm mass just below the right nipple, which shows multiple fissures. What finding is likely associated with her condition?
Your Answer: Staphylococcus aureus infection
Explanation:Breast abscess occur commonly in lactating mothers in the postpartum period due to cracking of the nipple. It is commonly caused due to Staphylococcus aureus infection. Fat necrosis usually results from trauma wherein an ill-defined mass is formed. Ductal carcinomas are malignant masses which are not tender usually, and rare in the young age group. Plasma cell mastitis affect women in an older age group. Sclerosing adenosis is a type of fibrocystic disease which can lead to a tender, cystic mass but no fissuring or cracks are seen in the nipple. Fibroadenoma and lipomas are non-tender, well-defined masses.
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This question is part of the following fields:
- Pathology
- Women's Health
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Question 29
Correct
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A man had noticed weakness in his left arm causing flexion of the elbow and supination of the forearm. Which nerve in this case was injured?
Your Answer: Musculocutaneous
Explanation:The musculocutaneous nerve supplies the biceps brachii and the brachialis muscles. The first one flexes the elbow and the shoulder. It is also involved in supination. The brachialis muscle flexes the forearm. The injury to the musculocutaneous nerve results in paralysis of these muscles.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 30
Incorrect
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A 75-year old patient is in atrial fibrallation but has never been on anticoagulation therapy. To reduce the risk of future emboli, she would benefit from starting on long-term warfarin. Arterial emboli leading to acute limb ischaemia most commonly lodge at which one of the following sites?
Your Answer: Popliteal artery
Correct Answer: Common femoral artery
Explanation:The common femoral artery is the commonest site of arterial emboli causing acute limb ischemia. The treatment of choice is urgent femoral embolectomy.
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This question is part of the following fields:
- Cardiovascular
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
