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Question 1
Incorrect
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What is the chief ligament preventing posterior sliding of the tibia on the femur ?
Your Answer: Anterior cruciate
Correct Answer: Posterior cruciate
Explanation:The posterior cruciate ligament is attached to the posterior intercondyloid fossa of the tibia and the lateral and front part of the medial condyle of the femur. It resists sliding of the tibia posteriorly.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 2
Correct
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A 16 year old girl fractured a bone in her left foot. Upon examination the clinician discovered that the fracture affected the insertion of the peroneus brevis muscle. Which of the following bones was most likely affected?
Your Answer: Base of the fifth metatarsal
Explanation:The peroneus brevis muscle originates from the lower two-thirds of the lateral body of the fibula and has inserts at the base of the fifth metatarsal. Fractures to this bone are common and can be due to infection, trauma, overuse and repetitive use.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 3
Incorrect
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The basilar artery arises from the confluence of which two arteries?
Your Answer: Internal carotid
Correct Answer: Vertebral
Explanation:The basilar artery is part of the vertebrobasilar system. It is formed by the confluence of the two vertebral arteries which arise from the subclavian arteries. These two vertebral arteries merge at the level of cranial nerve VI at the junction between the pons and the medulla oblangata to form what is know as the basilar artery. This vertebrobasilar system supplies the upper spinal cord, brainstem, cerebellum, and posterior part of brain.
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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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An experiment is carried out to observe engulfment and phagocytosis of microbes. Strep pneumoniae are added to a solution of leukocytes with a substance added to enhance the process of phagocytosis. What is this substance?
Your Answer: Complement C3b
Explanation:C3b is cleaved from C3 complement with the help of the enzyme C3- convertase. It binds to the cell surface of the offending substance and opsonizes it. This makes it easy for the phagocytes to detect and eliminate them.
IgM does not act as an opsonin but igG does.
Selectins aid leukocytes to bind to the endothelial surfaces.
C5a is a chemo-attractant and histamine a vasodilator.
NADPH oxidises offending substance after phagocytosis within the macrophage.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 5
Incorrect
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A 35 year-old woman is undergoing thyroidectomy. The external laryngeal nerve may be injured whilst ligating this artery during the procedure due to its close relationship?
Your Answer: Inferior thyroid artery
Correct Answer: Superior thyroid artery
Explanation:The superior thyroid artery arises from the external carotid artery just below the level of the greater cornu of the hyoid bone and ends in the thyroid gland. This artery must be ligated at the thyroid when conducting a thyroidectomy. If the artery is severed, but not ligated, it will bleed profusely. In order to gain control of the bleeding, the surgeon may need to extend the original incision laterally to ligate the artery at its origin at the external carotid artery. The external laryngeal branch of the superior laryngeal nerve courses in close proximity to the superior thyroid artery, making it at risk for injury during surgery.
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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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A 7-year old child from a rural setting complains of recurrent abdominal pain. The child is found to have a heavy parasitic infestation and anaemia. Which type of anaemia is most likely seen in this patient?
Your Answer: Iron deficiency anaemia
Explanation:The most common cause of iron deficiency anaemia in children in developing countries is parasitic infection (hookworm, amoebiasis, schistosomiasis and whipworm).
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 7
Correct
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A 30-year old lady was admitted to the general surgical ward after a diagnosis of perforation of the first part of the duodenum that resulted from a long standing ulcer. If this perforation led to the expulsion of the gastric content that resulted to the erosion of an artery found in this part of the duodenum (the posterior of the first part of the duodenum). Which of the following arteries is this most likely to be?
Your Answer: Gastroduodenal
Explanation:The proximal part of the duodenum is supplied by the gastroduodenal artery. This artery is found descending behind the first part of the duodenum after branching from the hepatic artery. If gastric content was to be expelled in the posterior portion of the first part of the duodenum, then this artery would be most likely to be damaged. The common hepatic artery and the left gastric artery are branches of the coeliac trunk that are found superior to the duodenum. The proper hepatic artery is a branch of the common hepatic artery also found superior to the duodenum. The superior mesenteric artery is found behind the pancreas as a branch of the aorta that is at the bottom of the L1 level. The right gastric artery arises above the pylorus from the proper hepatic artery and supplies the lesser curvature of the stomach. The intestinal arteries supply the ileum and the jejunum.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 8
Incorrect
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In a cardiac cycle, what event does the closing of atrioventricular (AV) valves coincide with?
Your Answer: End of isovolumic relaxation
Correct Answer: First heart sound
Explanation:In the cardiac cycle, the closing of the atrioventricular (AV) valves coincides with the onset of ventricular systole. This event marks the beginning of the isovolumetric contraction phase, where the ventricles begin to contract, but the volume of blood in the ventricles remains the same because both the AV valves and the semilunar valves (aortic and pulmonary valves) are closed. The closing of the AV valves produces the first heart sound, known as “S1” or “lub.”
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 9
Correct
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Which tumour site is more commonly involved in adults than in children?
Your Answer: Lung
Explanation:In adults, the most common primary site of tumour is in the lungs, compared to children wherein the most common primary site is the blood.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 10
Incorrect
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A 38 year-old man falls on an outstretched hand. X-rays indicate an anterior dislocation of one of the carpal bones. Which carpal bone is most commonly dislocated?
Your Answer: Scaphoid
Correct Answer: Lunate
Explanation:The scaphoid bone is the most commonly fractured carpal bone and has an increased risk of avascular necrosis.
The lunate is the most commonly dislocated carpal bone. The displaced bone may compress the median nerve in the carpal tunnel.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 11
Correct
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When a patient that is less than 21 years of age develops a bone tumour. What is the most common benign bone tumour that would be considered in individuals below 21 years?
Your Answer: Osteochondroma
Explanation:Osteochondroma is a benign new bone growth that protrudes from the outer contour of bones and is capped by growing cartilage. Nearly 80% of these lesions are noted before the age of 21 years.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 12
Correct
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Which of the following tumours is very radiosensitive?
Your Answer: Seminoma
Explanation:Seminoma is the most radiosensitive tumour and responds well to radiation therapy after unilateral orchidectomy. The ipsilateral inguinal areas are routinely not treated however, depending on the stage, the mediastinum and the left supraclavicular regions may also be irradiated.
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This question is part of the following fields:
- Neoplasia; Urology
- Pathology
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Question 13
Incorrect
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A 58-year-old woman diagnosed with deep vein thrombosis had been using warfarin for 10 days. When she presented to the doctor she had haemorrhagic bullae and necrotic lesions in her lower limbs and buttocks. Deficiency of which of the following proteins may have caused the necrotic skin lesions?
Your Answer: Protein Z
Correct Answer: Protein C
Explanation:Warfarin-induced skin necrosis is a rare complication of anticoagulant therapy that requires immediate drug cessation. The most common cutaneous findings include petechiae that progress to ecchymoses and haemorrhagic bullae. Warfarin inactivates vitamin K-dependent clotting factors II, VII, IX, and X and vitamin K-dependent proteins C and S. The concentration of protein C falls more rapidly than other vitamin K-dependent factors because they have a shorter half-lives. Skin necrosis is seen mainly in patients with prior protein C deficiency.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 14
Correct
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After having donated a unit of blood. The blood bank will prefer to use which of the following anticoagulants to store the blood?
Your Answer: Citrate
Explanation:Calcium is necessary for coagulation to occur. Citrate being a chelator and combining with calcium ions to form un-ionised compound will prevent coagulation. Following transfusion the citrate is removed by the liver with in a few minutes. Oxalate also works on the same principle but it is toxic to the body.
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This question is part of the following fields:
- General
- Physiology
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Question 15
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 16
Correct
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Post-total gastrectomy, there will be a decreased production of which of the following enzymes?
Your Answer: Pepsin
Explanation:Pepsin is a protease that is released from the gastric chief cells and acts to degrade proteins into peptides. Released as pepsinogen, it is activated by hydrochloric acid and into pepsin itself. Gastrin and the vagus nerve trigger the release of pepsinogen and HCl when a meal is ingested. Pepsin functions optimally in an acidic environment, especially at a pH of 2.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 17
Incorrect
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During uterogrowth, the second pharyngeal arch gives rise to which structures?
Your Answer: Malleus
Correct Answer: Stylohyoid muscle
Explanation:The second pharyngeal arch or hyoid arch, is the second of six pharyngeal arches that develops in fetal life during the fourth week of development and assists in forming the side and front of the neck. Derivatives:
Skeletal – From the cartilage of the second arch arises:
Stapes,
Temporal styloid process,
Stylohyoid ligament, and
Lesser cornu of the hyoid bone.
Muscles:
Muscles of face
Occipitofrontalis muscle
Platysma
Stylohyoid muscle
Posterior belly of Digastric
Stapedius muscle
Auricular muscles
Nerve supply: Facial nerve
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 18
Incorrect
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A patient presents with loss of pain and temperature sensation in the left leg. He is likely to have a lesion involving:
Your Answer: Right anterior spinothalamic tract
Correct Answer: Right lateral spinothalamic tract
Explanation:The spinothalamic tract is a sensory pathway originating in the spinal cord that transmits information to the thalamus. There are two main parts of the spinothalamic tract: the lateral spinothalamic tract transmits pain and temperature and the anterior spinothalamic tract transmits touch (crude touch). The decussation of this pathway occurs at the level of the spinal cord. Hence, a unilateral lesion of the lateral spinothalamic tract causes contralateral loss of pain and temperature.
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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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The specimen sent to the pathologist for examination was found to be benign. Which one of the following is most likely a benign tumour?
Your Answer: Warthin’s tumour
Explanation:Warthin’s tumour is also known as papillary cystadenoma lymphomatosum. It is a benign cystic tumour of the salivary glands containing abundant lymphocytes and germinal centres. It has a slightly higher incidence in males and most likely occur in older adults aged between 60 to 70 years. This tumour is also associated with smoking. Smokers have an eight-fold greater risk in developing the tumour compared to non-smokers.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 20
Correct
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A 59-year old gentleman admitted for elective cholecystectomy was found to have a haemoglobin 12.5 g/dl, haematocrit 37%, mean corpuscular volume 90 fl, platelet count 185 × 109/l, and white blood cell count 32 × 109/l; along with multiple, small mature lymphocytes on peripheral smear. The likely diagnosis is:
Your Answer: Chronic lymphocytic leukaemia
Explanation:CLL or chronic lymphocytic leukaemia is the most common leukaemia seen in the Western world. Twice more common in men than women, the incidence of CLL increases with age. About 75% cases are seen in patients aged more than 60 years. The blood, marrow, spleen and lymph nodes all undergo infiltration, eventually leading to haematopoiesis (anaemia, neutropenia, thrombocytopenia), hepatomegaly, splenomegaly and decreased production of immunoglobulin. In 98% cases, CD+5 B cells undergo malignant transformation.
Often diagnosed on blood tests while being evaluated for lymphadenopathy, CLL causes symptoms like fatigue, anorexia, weight loss, pallor, dyspnoea on exertion, abdominal fullness or distension. Findings include multiple lymphadenopathy with minimal-to- moderate hepatomegaly and splenomegaly. Increased susceptibility to infections is seen. Herpes Zoster is common. Diffuse or maculopapular skin infiltration can also be seen in T-cell CLL.
Diagnosis is by examination of peripheral blood smear and marrow: hallmark being a sustained, absolute leucocytosis (>5 ×109/l) and increased lymphocytes in the marrow (>30%). Other findings can include hypogammaglobulinemia (<15% of cases) and, rarely, raised lactate dehydrogenase (LDH). Only 10% cases demonstrate moderate anaemia and/or thrombocytopenia.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 21
Incorrect
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Which of the following muscles aid in inspiration?
Your Answer: Abdominal muscles and external intercostals
Correct Answer: Diaphragm and external intercostals
Explanation:The diaphragm and external intercostals are muscles of inspiration as they increase the volume of thoracic cavity and reduce the intrathoracic pressure. Muscles of expiration include abdominal muscles and internal intercostals.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 22
Incorrect
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A 50 year old man was admitted to the surgical ICU following a hemicolectomy for carcinoma of the caecum. A full blood count revealed: haematocrit = 30%, erythrocytes = 4 × 106/μ, haemoglobin level = 8 g/dl. To determine the likely cause of his anaemia, red blood cell indices were calculated. Which RBC indices are correct?
Your Answer: MCHC = reticulocyte count/ haemoglobin conc.
Correct Answer: MCHC = haemoglobin concentration/haematocrit
Explanation:Mean corpuscular haemoglobin concentration (MCHC) is calculated simply by dividing the haemoglobin concentration (8 g/dl) by the haematocrit (0.3). The normal range is 31–36 g/dl. This patient has a hypochromic anaemia (MCHC = 8/0.3 = 26.7 g/dl). Dividing the haemoglobin concentration × 10 by erythrocyte number yields mean corpuscular haemoglobin (MCH). Normal range is 25.4–34.6 pg/cell and this patient has a significantly reduced cellular haemoglobin content (MCH = 8 × 10/4 = 20 pg/cell). Mean corpuscular volume (MCV) is calculated by dividing haematocrit × 1000 by erythrocyte number (4 × 106/μl). Normal range is 80–100 fl and this patient has a microcytic anaemia (MCV = 0.3 × 1000/4 = 75 fl). Microcytic, hypochromic anaemia is characteristic for iron-deficiency.
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This question is part of the following fields:
- General
- Physiology
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Question 23
Incorrect
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A 40-year old gentleman, known with a history of peptic ulcer disease, was brought to the clinic in a dehydrated state with persistent vomiting. His blood investigations revealed:
- sodium = 142 mmol/l
- potassium = 2.6 mmol/l
- chloride = 85 mmol/l
- pH = 7.55
- p(CO2) = 50 mmHg
- p(O2) = 107 mmHg
- standard bicarbonate = 40 mmol/l
Your Answer: Respiratory acidosis
Correct Answer: Metabolic alkalosis
Explanation:High pH with high standard bicarbonate indicates metabolic alkalosis. The pa(CO2) was appropriately low in compensation. This is hypokalaemic hypochloraemic metabolic acidosis due to prolonged vomiting. Treatment includes treating the cause and intravenous sodium chloride with potassium.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 24
Correct
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A 34-year-old woman has been suffering from headaches, fever, vomiting, and confusion for the last 5 days. A CT scan reveals an oedematous mass with ring enhancement in the left temporal region. It is biopsied, revealing glial cells, necrosis, neutrophils and lymphocytes. What is the most likely diagnosis?
Your Answer: Cerebral abscess
Explanation:A cerebral abscess can result from direct extension of cranial infections, penetrating head trauma, haematogenous spread, or for unknown causes. An abscess forms when an area of cerebral inflammation becomes necrotic and encapsulated by glial cells and fibroblasts. Oedema around the abscess can increase the intracranial pressure. Symptoms result from increased intracranial pressure and mass effects. It is most frequent in the third decade of life, and when it occurs in children, it is usually associated with congenital heart disease.
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This question is part of the following fields:
- Neurology
- Pathology
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Question 25
Incorrect
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There are several mechanisms involved in the transport of sodium ions from blood to interstitial fluid of the muscle cells. Which of the following mechanisms best describes this phenomenon?
Your Answer: Active transport through endothelial cell membranes
Correct Answer: Diffusion through channels between endothelial cells
Explanation:Capillaries are the smallest of the body’s blood vessels, measuring 5–10 μm and they help to enable the exchange of water, oxygen, carbon dioxide, and many other nutrients and waste substances between the blood and the tissues surrounding them. The walls of capillaries are composed of only a single layer of cells, the endothelium. Ion channels are pore-forming proteins that help to establish and control the small voltage gradient that exists across the plasma membrane of all living cells by allowing the flow of ions down their electrochemical gradient. An ion channel is an integral membrane protein or more typically an assembly of several proteins. The archetypal channel pore is just one or two atoms wide at its narrowest point. It conducts a specific ion such as sodium or potassium and conveys them through the membrane in single file.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 26
Incorrect
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Which of the following is the most likely cause of massive splenomegaly in a 35-year old gentleman?
Your Answer: Haemochromatosis
Correct Answer: Myelofibrosis
Explanation:Causes of massive splenomegaly include chronic myelogenous leukaemia, chronic lymphocytic leukaemia, lymphoma, hairy cell leukaemia, myelofibrosis, polycythaemia vera, sarcoidosis, Gaucher’s disease and malaria.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 27
Incorrect
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You are asked to help a junior medical student studying anatomy to identify the left lung. Which of the following features found only in the left lung will you use the identify it?
Your Answer: Superior lobar bronchus
Correct Answer: Cardiac notch
Explanation:Oblique fissure: is found on both the left and the right lungs. It separates the upper from the lower lobes in both lungs and the middle lobe from the lower lobe in the right lung(which has three lobes.)
The superior lobar bronchus is found in both lungs.
Cardiac notch: found only on the left lung.
Horizontal fissure: a deep groove separating the middle lobe from the upper lobe of the right lung is absent on the left lung.
Diaphragmatic surface: refers to the part of the lung, both the left and the right, that is in contact with the diaphragm.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 28
Incorrect
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T lymphocytes that express the MCH type II antigen are most likely to produce which of the following cytokines?
Your Answer: Tumour necrosis factor
Correct Answer: Gamma interferon
Explanation:Interferon gamma is a soluble cytokine previously known as the macrophage activating factor. It is the only member belonging to the type II class of the interferons. It is secreted by a number of cells taking part in the immune reaction including: T-helper cells (CD-4), cells with immunological memory (CD45PA), killer cells (CD8), dendrite cells (CD23,35), natural killer cells (CD16) and B lymphocytes (CD22,CD23). It has both a defending as well as a pathological effect. It induces differentiation in the myeloid cell in the bone marrow. If macrophages are infected by parasites it activates the macrophages to destroy them. IFN-γ strengthens the anti-tumour activities of the cytotoxic lymphocytes. Together with CD4 or CD8 toxins, produced by lymphocytes, it suppresses the growth of the tumour cells. along with these functions it increases the non specific response of the natural killer cells, causing changes in the cell membrane surface to prevent adhesion and penetration of a virus. It can either increase or decrease B cell response and it activates osteoclasts which increases bone resorption.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 29
Incorrect
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A 50-year-old man is diagnosed with emphysema and cirrhosis of the liver. Which of the following condition may be the cause of both cirrhosis and emphysema in this patient?
Your Answer: Cystic fibrosis
Correct Answer: Alpha1-antitrypsin deficiency
Explanation:Alpha-1 antitrypsin (A1AT) deficiency is a condition characterised by the lack of a protein that protects the lungs and liver from damage, called alpha1-antytripsin. The main complications of this condition are liver diseases such as cirrhosis and chronic hepatitis, due to accumulation of abnormal alpha 1-antytripsin and emphysema due to loss of the proteolytic protection of the lungs.
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This question is part of the following fields:
- Pathology
- Respiratory
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Question 30
Incorrect
SESSION STATS - PERFORMANCE PER SPECIALTY
