-
Question 1
Correct
-
An elderly, diabetic man has firm, tender nodules at the base of his left middle and ring fingers, which he can't extend fully. What's the most likely diagnosis?
Your Answer: Fibromatosis
Explanation:This case is suggestive of Dupuytren’s contracture due to palmar fibromatosis. Its incidence is higher in men over the age of 45 years, and it increases in patients with diabetes, alcoholism, or epilepsy. These nodules are benign, usually appearing as a tender nodule in the palm which becomes painless. The disease has an aggressive clinical behaviour and recurs frequently.
-
This question is part of the following fields:
- Orthopaedics
- Pathology
-
-
Question 2
Incorrect
-
During an operation to repair an indirect inguinal hernia, it is noticed that the hernial sac is protruding out of the superficial inguinal ring. The superficial inguinal ring is an opening in which structure?
Your Answer: Scarpa’s fascia
Correct Answer: External abdominal oblique aponeurosis
Explanation:The superficial inguinal ring is an opening in the aponeurosis of the external oblique just above and lateral to the pubic crest. The opening is oblique and corresponds to the fibres of the aponeurosis. It is bound inferiorly by the pubic crest, on either side by the margins of the opening in the aponeurosis and superiorly by the curved intercrural fibres.
The inferior crus is formed by the portion of the inguinal ligament that is inserted into the pubic tubercle.
The falx inguinalis is made of arching fibres of the transversalis fascia and the internal abdominal oblique muscle. It forms the posterior wall of the inguinal canal.
The internal abdominal oblique forms the root of the inguinal canal.
Scarpa’s and Camper’s fascia are the membranous and fatty layers, respectively of subcutaneous fascia.
Transversalis fascia covers the posterior surface of the rectus abdominis muscle inferior to the arcuate line.
-
This question is part of the following fields:
- Abdomen
- Anatomy
-
-
Question 3
Correct
-
A computer tomography guided needle biopsy is done on a patient with a cystic swelling in the left chest. The radiologist inserted the biopsy needle into the 9th intercostal space along the mid axillary line to aspirate the swelling and obtain tissue for histological diagnosis. In which space is the swelling most likely to be?
Your Answer: Costodiaphragmatic recess
Explanation:The costodiaphragmatic recess is the lowest point of the pleural sac where the costal pleura becomes the diaphragmatic pleura. At the midclavicular line, this is found between ribs 6 and 8; at the paravertebral lines, between ribs 10 and 12 and between ribs 8 and 10 at the midaxillary line.
The cardiac notch: is an indentation of the heart on the left lung, located on the anterior surface of the lung.
Cupola: part of the parietal pleura that extends above the first rib.
Oblique pericardial sinus: part of the pericardial sac located posterior to the heart behind the left atrium.
Costomediastinal recess: a reflection of the pleura from the costal surface to the mediastinal surface, is on the anterior surface of the chest.
The inferior mediastinum: is the space in the chest occupied by the heart.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 4
Incorrect
-
Which of the following substances brings about a dilatation of the gastrointestinal resistance vessels?
Your Answer: Vasopressin
Correct Answer: Vasoactive intestinal peptide
Explanation:Gastric vasoconstrictors include catecholamines, angiotensin II and vasopressin. Vasodilators include vasoactive intestinal peptide and the hormones; gastrin, cholecystokinin and glucagon.
-
This question is part of the following fields:
- Gastroenterology
- Physiology
-
-
Question 5
Correct
-
The primary motor cortex is located in the:
Your Answer: Precentral gyrus
Explanation:The primary motor cortex is located in the dorsal part of the precentral gyrus and the anterior bank of the central sulcus. The precentral gyrus lies anterior to the postcentral gyrus and is separated from it by a central sulcus. Its anterior border is the precentral sulcus, while inferiorly it borders to the lateral fissure (Sylvian fissure).
-
This question is part of the following fields:
- Neurology
- Physiology
-
-
Question 6
Incorrect
-
An infant, 5 weeks and 6 days old born with a large sub-aortic ventricular septal defect, is prepared for pulmonary artery banding through a left thoracotomy (the child is not fit for a surgical closure). The surgeon initially passes his index finger immediately behind two great arteries in the pericardial sac to mobilise the great arteries in order to pass the tape around the pulmonary artery. Into which space is the surgeon's finger inserted?
Your Answer: Oblique pericardial sinus
Correct Answer: Transverse pericardial sinus
Explanation:Cardiac notch: is an indentation on the left lung of the heart.
Coronary sinus: a venous sinus on the surface of the heart (the posterior aspect) that receives blood from the smaller veins that drain the heart.
Coronary sulcus: a groove on the heart between the atria and ventricles.
Transverse pericardial sinus: located behind the aorta and pulmonary trunk and anterior to the superior vena cava.
Oblique pericardial sinus: located behind the left atrium. Accessed from the inferior side (or the apex) of the heart upwards.
Horizontal pericardial sinus: this is a made-up term.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 7
Incorrect
-
Which of the following is true about myasthenia gravis?
Your Answer: The patient should be given α-bungarotoxin to determine the number of acetylcholine binding sites at the post junctional membrane
Correct Answer: Response of skeletal muscle to nerve stimulation is weakened
Explanation:An autoimmune disorder, myasthenia gravis leads to progressive muscle weakness. It occurs due to formation of antibodies against the nicotinic acetylcholine (ACh) receptor of the motor endplate, which leads to impaired neuromuscular transmission. Thus, nerve stimulation will lead to a weakened muscle response, but direct electrical stimulation will bring about a normal response. Diagnostic test includes improvement of muscle weakness by small doses of acetylcholinesterase inhibitors (physostigmine or edrophonium). However, a large dose of physostigmine worsens the weakness due to desensitisation of the endplate to persistent Ach. One of the investigative tools includes radiolabelled snake venom α-bungarotoxin. It is an in vitro study performed on muscle biopsy specimens and used to quantify the number of ACh receptors at the motor endplate.
-
This question is part of the following fields:
- Neurology
- Physiology
-
-
Question 8
Incorrect
-
A patient is unable to move their mandible to the left. Which muscle is affected in this case?
Your Answer: Left lateral pterygoid muscle
Correct Answer: Right lateral pterygoid muscle
Explanation:Patients with paralysis of the right pterygoid muscle are unable to move their mandible laterally to the left.
-
This question is part of the following fields:
- Anatomy
- Head & Neck
-
-
Question 9
Incorrect
-
Loperamide is a drug used to treat diarrhoea. What is the mechanism of action of loperamide?
Your Answer: Irreversibly inhibits H+/K+-ATPase
Correct Answer: Opiate agonist
Explanation:Loperamide is an opioid-receptor agonist and acts on the mu opioid receptors in the myenteric plexus of large intestine. It works by decreasing the motility of the circular and longitudinal smooth muscles of the intestinal wall. It is often used for this purpose in gastroenteritis, inflammatory bowel disease, and short bowel syndrome.
-
This question is part of the following fields:
- Pathology
- Pharmacology
-
-
Question 10
Incorrect
-
Which nerve mediates the sensation to itch from the skin that is just over the base of the spine of your scapula?
Your Answer: Dorsal root of T2
Correct Answer: Dorsal primary ramus of C7
Explanation:The first branches off spinal nerves are called the dorsal and ventral rami. The dorsal rami mediate sensation of the skin over the back and motor supply to the true muscles of the back whilst the ventral rami gives sensation to the skin over the limbs and the skin that is over the ventral side of the trunk. It also gives motor supply to the skeletal muscles of the neck, the trunk and extremities. Hence, itchiness of the part of the skin that is over the spine of the scapula would be mediated by the primary ramus of C7. Accessory nerve doesn’t have any sensory innervation.
-
This question is part of the following fields:
- Anatomy
- Neurology
-
-
Question 11
Incorrect
-
Which of the following physiological changes will you see in a young man who has been trekking in the Himalayas for 3 years?
Your Answer:
Correct Answer: Increased renal excretion of HCO3 –
Explanation:The atmospheric pressure is lower at high altitudes as compared with sea level. This leads to a decrease in the partial pressure of oxygen. Once 2100 m (7000 feet) of altitude is reached, there is a drop in saturation of oxyhaemoglobin. The oxygen saturation of haemoglobin determines the oxygen content in the blood. The body physiological tries to adapt to high altitude by acclimatization. Immediate effects include hyperventilation, fluid loss (due to a decreased thirst drive), increase in heart rate and slightly lowered stroke volume. Long term effects include lower lactate production, compensatory alkali loss in urine, decrease in plasma volume, increased erythropoietin release and red cell mass, increased haematocrit, higher concentration of capillaries in striated muscle tissue, increase in myoglobin, increase in mitochondria, increase in aerobic enzyme concentration such as 2,3-DPG and pulmonary vasoconstriction.
-
This question is part of the following fields:
- Physiology
- Respiratory
-
-
Question 12
Incorrect
-
A 40 year old man suffered severe trauma following an MVA. His BP is 70/33 mmhg, heart rate of 140 beats/mins and very feeble pulse. He was transfused 3 units of blood resulting in his BP returning to 100/70 and his heart rate to 90 beats/min. What decreased following transfusion?
Your Answer:
Correct Answer: Total peripheral resistance
Explanation:The patient is in hypovolemic shock, he is transfused with blood to replace the volume lost. It is important not only to replace fluids but stop active bleeding in resuscitation. Fluid replacement will result in a decreased sympathetic discharge and adequate ventricular filling thus reducing total peripheral resistance and increasing cardiac output and cardiac filling pressures.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 13
Incorrect
-
Which of these nerves controls adduction of hand?
Your Answer:
Correct Answer: Ulnar nerve
Explanation:The adductors of the fingers are the palmer interossei. They are supplied by the ulnar nerve, which is a branch of the medical cord of the brachial plexus.
-
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 14
Incorrect
-
Which of the following conditions can present with multiple abscesses that may discharge sulphur granules?
Your Answer:
Correct Answer: Actinomycosis
Explanation:Actinomycosis is primarily caused by any of the several members of the bacterial genus Actinomyces. These bacteria are generally anaerobes. And can cause multiple abscesses that may discharge sulphur granules.
-
This question is part of the following fields:
- Microbiology
- Pathology
-
-
Question 15
Incorrect
-
A Jewish man was diagnosed with haemophilia C. Which of the following factors is deficient in this form of haemophilia?
Your Answer:
Correct Answer: Factor XI
Explanation:Haemophilia C, also known as plasma thromboplastin antecedent (PTA) deficiency or Rosenthal syndrome, is a condition caused by the deficiency of the coagulation factor XI. The condition is rare and it is usually found in Ashkenazi Jews.
-
This question is part of the following fields:
- Haematology
- Pathology
-
-
Question 16
Incorrect
-
A man in his sixties underwent surgery to remove a lump from his axilla. During removal, a nerve originating from the lateral cord of the brachial plexus was damaged. Which nerve is this referring to?
Your Answer:
Correct Answer: Lateral pectoral
Explanation:The only branch of the lateral cord of brachial plexus in the options given, is the lateral pectoral nerve. It supplies the pectoralis major muscle and sends a branch to join the medial pectoral nerve forming a loop in front of the first part of the axillary artery.
-
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 17
Incorrect
-
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:
Correct 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.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 18
Incorrect
-
What is the correct order of structures a needle must pass before it enters the pleural cavity?
Your Answer:
Correct Answer: External intercostals – internal intercostals – innermost intercostals – parietal pleura
Explanation:The correct order of structures from superficial to deep are: the skin and subcutaneous tissue, the external intercostals followed by internal intercostals, innermost intercostals and finally parietal pleura.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 19
Incorrect
-
After a severe asthma attack, a 26-year-old woman is left in a markedly hypoxic state. In which of the following organs are the arterial beds most likely to be vasoconstricted due to the hypoxia?
Your Answer:
Correct Answer: Lungs
Explanation:Hypoxic pulmonary vasoconstriction is a local response to hypoxia resulting primarily from constriction of small muscular pulmonary arteries in response to reduced alveolar oxygen tension. This unique response of pulmonary arterioles results in a local adjustment of perfusion to ventilation. This means that if a bronchiole is obstructed, the lack of oxygen causes contraction of the pulmonary vascular smooth muscle in the corresponding area, shunting blood away from the hypoxic region to better-ventilated regions. The purpose of hypoxic pulmonary vasoconstriction is to distribute blood flow regionally to increase the overall efficiency of gas exchange between air and blood.
-
This question is part of the following fields:
- Physiology
- Respiratory
-
-
Question 20
Incorrect
-
Which of the following tumours is very radiosensitive?
Your Answer:
Correct 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.
-
This question is part of the following fields:
- Neoplasia; Urology
- Pathology
-
-
Question 21
Incorrect
-
Skeletal muscle fibres are divided into two basic types, type I (slow-twitch fibres) and type II (fast-twitch fibres). Fast muscle fibres do which of the following:
Your Answer:
Correct Answer: Use anaerobic metabolism
Explanation:Skeletal muscles are divided into two types:
1) type I also known as the slow twitch fibres. They use oxygen for their metabolism and as a result they have a high endurance potential. To support this they have abundant mitochondria and myoglobin, so they appear red/dark.
2) type II fibres also called fast twitch fibres, are low endurance fibres used during anaerobic metabolism. They are required for short bursts of strength and cannot sustain contractions for long periods of time.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 22
Incorrect
-
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:
Correct 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.
-
This question is part of the following fields:
- Anatomy
- Head & Neck
-
-
Question 23
Incorrect
-
What is the nerve supply of the muscle that is inserted onto the crest of the lesser tubercle of the humerus?
Your Answer:
Correct Answer: Lower subscapular
Explanation:The muscle is the subscapularis muscle which is supplied by the lower subscapular nerve.
-
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 24
Incorrect
-
A chloride sweat test was performed on a 13-year-old boy. Results indicated a high likelihood of cystic fibrosis. This diagnosis is associated with a higher risk of developing which of the following?
Your Answer:
Correct Answer: Bronchiectasis
Explanation:Cystic fibrosis is a life-threatening disorder that causes the build up of thick mucus in the lungs, digestive tract, and other areas of the body. It is a hereditary autosomal-recessive disease caused by mutations of the CFTR gene. Cystic fibrosis eventually results in bronchiectasis which is defined as a permanent dilatation and obstruction of bronchi or bronchioles.
-
This question is part of the following fields:
- Pathology
- Respiratory
-
-
Question 25
Incorrect
-
A histology report of a cervical biopsy taken from a patient with tuberculosis revealed the presence of epithelioid cells. What are these cells formed from?
Your Answer:
Correct Answer: Macrophages
Explanation:Granulomas formed in tuberculosis are called tubercles and are made up polynuclear phagocytes, Langhans cells and epithelioid cells. Macrophages when enlarged, consist of abundant cytoplasm and have a tendency of arranging themselves very closely to each other representing epithelial cells. These enlarged macrophages are therefore termed as epithelioid cells.
-
This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
-
-
Question 26
Incorrect
-
A 7-year-old girl is given cephalexin to treat an infection and develops hives, with localised facial oedema. Which of the following conditions will cause localised oedema?
Your Answer:
Correct Answer: Angio-oedema
Explanation:Angio-oedema, is the rapid swelling of the skin, mucosa and submucosal tissues. The underlying mechanism typically involves histamine or bradykinin. The version related to histamine is to due an allergic reaction to agents such as insect bites, food, or medications. The version related to bradykinin may occur due to an inherited C1 esterase inhibitor deficiency, medications e.g. angiotensin converting enzyme inhibitors, or a lymphoproliferative disorder.
-
This question is part of the following fields:
- Physiology
- Renal
-
-
Question 27
Incorrect
-
The absence of which of the following components characterizes the grey platelet syndrome (GPS)?
Your Answer:
Correct Answer: Alpha granules
Explanation:Grey platelet syndrome (GPS) is a rare inherited bleeding disorder associated with an almost total absence of α-granules and their contents. The syndrome is characterised by thrombocytopenia, enlarged platelets that have a grey appearance, myelofibrosis, and splenomegaly. Alpha granules store proteins and growth factors that promote platelet adhesiveness and wound healing. Patients with GPS develop symptoms and signs such as easy bruising, prolonged bleeding, and nose bleeds.
-
This question is part of the following fields:
- Haematology
- Pathology
-
-
Question 28
Incorrect
-
A 20-year old gentleman was brought to the emergency department with headache and nausea for 2 days. He also complained of intolerance to bright light and loud sounds. Lumbar puncture showed glucose < 45 mg/dl, protein > 5 mg/dl and neutrophil leucocytosis. The likely diagnosis is:
Your Answer:
Correct Answer: Meningitis
Explanation:Diagnosis of meningitis can be carried out with examination of cerebrospinal fluid (CSF) with a lumbar puncture (LP). In a case of bacterial meningitis, the CSF analysis will show:
– Opening pressure: > 180 mmH2O
– White blood cell count: 10–10 000/μl with neutrophil predominance
– Glucose: < 40 mg/dl – CSF glucose to serum glucose ratio: < 0.4 – Protein: > 4.5 mg/dl
– Gram stain: positive in > 60%
– Culture: positive in > 80%
– Latex agglutination: may be positive in meningitis due to Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Escherichia coli and group B streptococci
– Limulus, lysates: positive in Gram-negative meningitis
-
This question is part of the following fields:
- Neurology
- Physiology
-
-
Question 29
Incorrect
-
A 58-year-old woman presents with signs of inflammation in the first metatarsophalangeal joint: redness, swelling and pain. The analysis of synovial fluid reveals needle-shaped, strongly negatively birefringent crystals. What's the most likely diagnosis in this case?
Your Answer:
Correct Answer: Gout
Explanation:Gout is a rheumatic disease caused by the precipitation of monosodium urate crystals into tissues, usually joints. This causes acute or chronic pain; the acute illness initially affects only one joint, often the first metatarsophalangeal joint. The diagnosis of the disease requires the identification of crystal in the synovial fluid. These crystals are needle-shaped and strongly negatively birefringent.
-
This question is part of the following fields:
- Orthopaedics
- Pathology
-
-
Question 30
Incorrect
-
A 37-year-old woman with a history of rheumatic heart disease presents with 10 days recurrent low fever. Patient underwent laboratory work up and was diagnosed with infective endocarditis. What is the most likely organism that caused the infective endocarditis in this patient?
Your Answer:
Correct Answer: Streptococcus viridans
Explanation:Subacute bacterial endocarditis is often due to streptococci of low virulence, mainly streptococcus viridans. It is a mild to moderate illness which progresses slowly over weeks and months (>2weeks) and has low propensity to hematogenously seed to extracardiac sites.
-
This question is part of the following fields:
- Microbiology
- Pathology
-
-
Question 31
Incorrect
-
A surgeon ligates the left superior suprarenal artery whilst preforming a left adrenalectomy. Where does the left superior suprarenal artery originate?
Your Answer:
Correct Answer: Left inferior phrenic artery
Explanation:The superior suprarenal arteries arises from the inferior phrenic artery on either side.
-
This question is part of the following fields:
- Abdomen
- Anatomy
-
-
Question 32
Incorrect
-
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:
Correct 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.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 33
Incorrect
-
Injury to which of the following arteries is likely to affect the blood supply to the seminal vesicles?
Your Answer:
Correct Answer: Middle rectal
Explanation:Ligation of middle rectal artery is most likely to affect the blood supply of seminal vesicles since arteries supplying the seminal vesicles are derived from the middle and inferior vesical and middle rectal arteries.
-
This question is part of the following fields:
- Anatomy
- Pelvis
-
-
Question 34
Incorrect
-
After a cerebral infarction, which of these histopathogical findings is most likely to be found?
Your Answer:
Correct Answer: Liquefactive necrosis
Explanation:The brain has a high lipid content and typically undergoes liquefaction with ischaemic injury, because it contains little connective tissue but high amounts of digestive enzymes.
-
This question is part of the following fields:
- Neurology
- Pathology
-
-
Question 35
Incorrect
-
The tensor villi palatini muscle is a broad thin, ribbon-like muscle in the head that tenses the soft palate. Which of the following structures is associated with the tensor villi palatini muscle?
Your Answer:
Correct Answer: The hamulus of the medial pterygoid plate
Explanation:The pterygoid hamulus is a hook-like process at the lower extremity of the medial pterygoid plate of the sphenoid bone around which the tendon of the tensor veli palatini passes.
-
This question is part of the following fields:
- Anatomy
- Head & Neck
-
-
Question 36
Incorrect
-
Which of the following is a potential cause of a positive D-dimer assay?
Your Answer:
Correct Answer: Deep venous thrombosis
Explanation:A D-dimer test is performed to detect and diagnose thrombotic conditions and thrombosis. A negative result would rule out thrombosis and a positive result although not diagnostic, is highly suspicious of thrombotic conditions like a deep vein thrombosis, pulmonary embolism as well as DIC.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 37
Incorrect
-
What is the reason for a deranged thrombin clotting time?
Your Answer:
Correct Answer: Heparin therapy
Explanation:Thrombic clotting time is also known as thrombin time. It is clinically performed to determine the therapeutic levels of heparin. After plasma is isolated from the blood, bovine thrombin is added to it and the time it takes from the addition to clot is recorded. The reference interval is usually <21s. deranged results are indicative of heparin therapy, hypofibrinogenemia, hyperfibrinogenaemia or lupus anticoagulant.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 38
Incorrect
-
A 65-year-old smoker presents with painless haematuria, urinary frequency and urgency. He is diagnosed with bladder cancer. Which is the most likely type?
Your Answer:
Correct Answer: Transitional cell carcinoma
Explanation:90% of bladder cancers are transitional cell carcinomas derived from the bladder urothelium. Risk factors include industrial chemicals, smoking and infection. Schistosomiasis and bladder stones predispose to the squamous cell variety.
-
This question is part of the following fields:
- Neoplasia
- Pathology
-
-
Question 39
Incorrect
-
What is the normal amount of oxygen that is carried in the blood?
Your Answer:
Correct Answer: 20 ml oxygen/100 ml blood
Explanation:Normally, 100 ml of blood contains 15g haemoglobin and a single gram of haemoglobin can bind to 1.34 ml oxygen when 100% saturated. Thus, 15 × 1.34 = 20 ml O2/100 ml blood. The haemoglobin in venous blood that is leaving the tissues is about 75% saturated with oxygen, and hence it carries about 15 ml O2/100 ml venous blood. This implies that for each 10 ml of blood, 5 ml oxygen is transported to the tissues. With a p(O2) > 100 mm Hg, only 3 ml of oxygen is dissolved in every one litre of plasma. By increasing the pA(O2) by breathing 100% oxygen, one can add an extra amount of oxygen in the plasma, but the amount of oxygen carried by haemoglobin will not increase significantly as it is already > 95% saturated.
-
This question is part of the following fields:
- Physiology
- Respiratory
-
-
Question 40
Incorrect
-
The mechanism of action of streptokinase involves:
Your Answer:
Correct 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.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 41
Incorrect
-
Following an accident, a man was unable to extend the wrist and metacarpophalangeal joints, despite sensation being intact. Which nerve was likely damaged?
Your Answer:
Correct Answer: Posterior interosseous nerve
Explanation:The posterior interosseous nerve which causes, what is known as the posterior interosseous nerve syndrome. The nerve is compressed before it bifurcates to form the medial and lateral branches. The compression is beyond the origin of the branches to the radial wrist extensors and the radial sensory nerve. The result of such a case is paralysis of the digital extensors and the extensor carpi ulnaris, resulting in dorsoradial deviation of the wrist.
-
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 42
Incorrect
-
Driving pressure is considered to be a strong predictor of mortality in patients with ARDS. What is the normal mean intravascular driving pressure for the respiratory circulation?
Your Answer:
Correct Answer: 10 mmHg
Explanation:Driving pressure is the difference between inflow and outflow pressure. For the pulmonary circulation, this is the difference between pulmonary arterial (pa) and left atrial pressure (pLA). Normally, mean driving pressure is about 10 mmHg, computed by subtracting pLA (5 mmHg) from pA (15 mmHg). This is in contrast to a mean driving pressure of nearly 100 mmHg in the systemic circulation.
-
This question is part of the following fields:
- Physiology
- Respiratory
-
-
Question 43
Incorrect
-
Which condition presents with a positive urine dipstick test for blood, but no blood cells on urine microscopy?
Your Answer:
Correct Answer: Myoglobinuria
Explanation:Myoglobinuria, or presence of myoglobulin in the urine is seen due to rhabdomyolysis (muscle destruction). Common causes of rhabdomyolysis include trauma, electrical injuries, burns, venom and drugs. Damaged muscle leads to release of myoglobin in the blood. Ideally, the released myoglobin gets filtered and excreted by the kidneys. However, excess myoglobin can occlude the renal filtration system leading to acute tubular necrosis and acute renal dysfunction.
-
This question is part of the following fields:
- Pathology
- Renal
-
-
Question 44
Incorrect
-
In which of the following conditions will the oxygen-haemoglobin dissociation curve shift to the right?
Your Answer:
Correct Answer: Exercise
Explanation:The oxygen-haemoglobin dissociation curve plots saturated haemoglobin against the oxygen tension and is usually a sigmoid plot. Each molecule of haemoglobin can bind to four molecules of oxygen reversibly. Factors that can influence the binding include: pH, concentration of 2,3-diphosphoglycerate (2,3-DPG), temperature, type of haemoglobin molecules, and presence of toxins, especially carbon monoxide. Shape of the curve is due to interaction of bound oxygen molecules with the incoming molecules. The binding of first molecule is difficult, with easier binding of the second and third molecule and increase in difficulty with the fourth molecule – partly as a result of crowding and partly as a natural tendency of oxygen to dissociate.
Left shift of curve indicates haemoglobin’s increased affinity for oxygen (seen at lungs). Right shift indicates decreased affinity and is seen with an increase in body temperature, hydrogen ions, 2,3-diphosphoglycerate (DPG), carbon dioxide concentration and exercise. Under normal resting conditions in a healthy individual, the normal position of the curve is at a pH of 7.4. A shift in the position of the curve with a change in pH is called the Bohr effect. Left shift occurs in acute alkalosis, decrease in p(CO2), decrease in temperature and decrease in 2,3-DPG. The fetal haemoglobin curve is to the left of the adult haemoglobin to allow for oxygen diffusion across the placenta. The curve for myoglobin is even further to the left. Carbon monoxide has a much higher affinity for haemoglobin than oxygen does. Thus, carbon monoxide poisoning leads to hypoxia.
-
This question is part of the following fields:
- Physiology
- Respiratory
-
-
Question 45
Incorrect
-
A butcher accidentally cut himself on his right index finger. Which of the following substances when in contact with the basement membrane of the injured vasculature will activate the coagulation cascade as well as the kinin system in a first response to this injury?
Your Answer:
Correct Answer: Hageman factor
Explanation:Hageman factor/factor XII in the intrinsic pathway activates prekallikrein and factor XI. Deficiency will not cause excessive bleeding as other coagulation factors will be utilized but the PTT will be greater than 200 seconds.
Thromboxane promotes platelet aggregation and causes vasoconstriction.
Plasmin, which is cleaved from plasminogen acts as an anticoagulant which breaks down thrombi.
Platelet activating factor promotes platelet aggregation and is also chemotactic to neutrophils.
Histamine acts as a vasodilator.
Platelet inhibiting factor acts an anticoagulant.
Renin is a hormone released from the kidney that causes vasoconstriction and water retention.
-
This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
-
-
Question 46
Incorrect
-
The middle meningeal artery is the largest among the arteries that supplies that dura mater of the brain. The middle meningeal artery is a branch of the?
Your Answer:
Correct Answer: Maxillary artery
Explanation:The middle meningeal artery is the largest of the three (paired) arteries that supply the meninges.
The middle meningeal artery is a large arterial branch of the maxillary artery which is a terminal branch of the external carotid artery. Upon originating, the middle meningeal artery passes through the foramen spinosum. In the skull, it courses in the middle cranial fossa where it provides several branches.
-
This question is part of the following fields:
- Anatomy
- Head & Neck
-
-
Question 47
Incorrect
-
A 14 year old girl suffers from haemophilia A and chronic knee pain with progressive swelling and deformity over the last 4 years. Test results reveal a significantly reduced factor VIII activity. Which of the following is seen in the knee joint space after an acute painful episode?
Your Answer:
Correct Answer: Cholesterol crystals
Explanation:Due to breakdown of the red blood cell membrane in haemophilic patients, cholesterol crystals are formed by the lipids. On the other hand lipofuscin deposition does not occur in haemolysis or haemorrhage. Neutrophil accumulation suggests acute inflammation. Anthracotic pigment is an exogenous carbon pigment that deposits in the lung from dust. Russell bodies are intracellular accumulations of immunoglobins in plasma cells. Curschmann’s spirals and Charcot Leyden crystals are pathognomonic of asthma.
-
This question is part of the following fields:
- Cell Injury & Wound Healing; Haematology
- Pathology
-
-
Question 48
Incorrect
-
A 53 year old women with a history of atrial fibrillation developed an acute abdomen. On laparoscopic examination her bowels appeared to be dusky to red-purple in colour and her mesenteric veins appeared to be patent. Which of the following is most likely to occur in this situation?
Your Answer:
Correct Answer: Wet gangrene
Explanation:Infarction of the small bowel following a sudden and complete occlusion of the mesenteric artery can involve any portion of the bowel, whether small or a large. The splenic flexure is at most risk for infarction as it is the watershed area between the superior and inferior mesenteric vessels. Regardless of whether the arterial or the venous blood vessels are occluded, because of the blood reflow into the damaged portion, it will appear haemorrhagic. The bowel appearing congested at first and then becoming oedematous. If the artery is occluded then there will be a clear cut demarcation and in venous occlusion the dusky colour fades with the rest of the normal bowel. Wet gangrene is characteristic of ischaemic injury to the gut.
-
This question is part of the following fields:
- Cell Injury & Wound Healing; Gastrointestinal
- Pathology
-
-
Question 49
Incorrect
-
Pseudomonas aeruginosa is a multidrug resistant pathogen that causes hospital-acquired infections. It is usually treated with piperacillin or another antibiotic. Which of the following is the other antibiotic?
Your Answer:
Correct Answer: Azlocillin
Explanation:Azlocillin, like piperacillin, is an acylampicillin antibiotic with an extended spectrum of activity and greater in vitro potency than the carboxypenicillins. Azlocillin is similar to mezlocillin and piperacillin. It demonstrates antibacterial activity against a broad spectrum of bacteria, including Pseudomonas aeruginosa.
-
This question is part of the following fields:
- Pathology
- Pharmacology
-
-
Question 50
Incorrect
-
A patient who following 20 years of working in the asbestos industry develops malignant mesothelioma and is scheduled for pleuropneumonectomy to remove the entire pleura and lung on the affected side. Which layer would provide a natural cleavage plane for surgical separation of the costal pleura from the thoracic wall?
Your Answer:
Correct Answer: Endothoracic fascia
Explanation:The endothoracic fascia is connective tissue that is between the costal parietal pleura and the inner aspect of the chest wall. Removing this layer of connective tissue would make it easy to separate the costal pleura from the thoracic wall.
Deep fascia: is not found around the lungs. It is a layer of connective tissue that invests a muscle or a group of muscles.
Parietal pleura: part of the pleura that lines the inner surface of the chest/thoracic cavity.
Visceral pleura: is the serous membrane that lines the surface of the lungs.
Transversus thoracis muscle fascia is associated only with the muscle transversus thoracis.
Peritracheal fascia: a layer of connective tissue that invests the trachea. It is not associated with the thoracic wall or the costal pleura.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
SESSION STATS - PERFORMANCE PER SPECIALTY
