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  • Question 1 - When does the heart rate decrease? ...

    Incorrect

    • When does the heart rate decrease?

      Your Answer: On inspiration

      Correct Answer: Pressure on the eyeball

      Explanation:

      Various vagotonic manoeuvres (e.g. Valsalva manoeuvre, carotid sinus massage, pressure on eyeballs, ice-water facial immersion, swallowing of ice-cold water) result in increased parasympathetic tone through the vagus nerve which results in a decrease in heart rate. These manoeuvres may be clinically useful in terminating supraventricular arrhythmias.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      49
      Seconds
  • Question 2 - The accumulation of eosinophils within tissues is mostly regulated by which of the...

    Incorrect

    • The accumulation of eosinophils within tissues is mostly regulated by which of the following cytokines?

      Your Answer: Tumour necrosis factor (TNF)

      Correct Answer: Interleukin-5

      Explanation:

      IL-5 is produced by TH2 helper cells and by mast cells. They stimulate increased secretion of immunoglobulins and stimulate B cell growth. They are the major regulators in eosinophil activation and control. They are also released from eosinophils and mast cells in asthmatic patients and are associate with a many other allergic conditions.

    • This question is part of the following fields:

      • Inflammation & Immunology
      • Pathology
      21.2
      Seconds
  • Question 3 - The presence of oval fat bodies in the urine is most likely to...

    Correct

    • The presence of oval fat bodies in the urine is most likely to be seen in which of the following conditions?

      Your Answer: Nephrotic syndrome

      Explanation:

      Nephrotic syndrome is associated with the presence of oval fat bodies on urinalysis due to increased proteinuria and lipiduria.

    • This question is part of the following fields:

      • Pathology
      • Renal
      35
      Seconds
  • Question 4 - QT interval in the electrocardiogram of a healthy individual is normally: ...

    Incorrect

    • QT interval in the electrocardiogram of a healthy individual is normally:

      Your Answer: 0.20 s

      Correct Answer: 0.40 s

      Explanation:

      QT interval extends from beginning of the QRS complex till the end of he T-wave and normally lasts for 0.40 s. It is important in the diagnosis of long-QT and short-QT syndrome. The QT interval varies on the basis of heart rate and may need to be corrected.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      15.3
      Seconds
  • Question 5 - Which of the following diseases is caused by intra-articular and/or extra-articular deposition of...

    Correct

    • Which of the following diseases is caused by intra-articular and/or extra-articular deposition of calcium pyrophosphate dihydrate (CPPD) crystals, due to unknown causes?

      Your Answer: Pseudogout

      Explanation:

      Pseudogout or chondrocalcinosis is a rheumatological disease caused by the accumulation of crystals of calcium pyrophosphate dihydrate (CPPD) in the connective tissues. It is frequently associated with other conditions, such as trauma, amyloidosis, gout, hyperparathyroidism and old age, which suggests that it is secondary to degenerative or metabolic changes in the tissues. The knee is the most commonly affected joint. It causes symptoms similar to those of rheumatoid arthritis or osteoarthritis.

    • This question is part of the following fields:

      • Orthopaedics
      • Pathology
      100.2
      Seconds
  • Question 6 - Calculate the resistance of the artery if the pressure at one end is...

    Incorrect

    • Calculate the resistance of the artery if the pressure at one end is 60 mmHg, pressure at the other end is 20 mm Hg and the flow rate in the artery is 200 ml/min.

      Your Answer: 0.05

      Correct Answer: 0.2

      Explanation:

      Flow in any vessel = Effective perfusion pressure divided by resistance, where effective perfusion pressure is the mean intraluminal pressure at the arterial end minus the mean pressure at the venous end. Thus, in the given problem, resistance = (60 − 20)/200 = 0.2 mmHg/ml per min.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      140.9
      Seconds
  • Question 7 - A 30-year old lady presented to her GP with complaints of tremors, excessive...

    Correct

    • A 30-year old lady presented to her GP with complaints of tremors, excessive emotional outbursts, weight loss and increased sweating over 20 days. On examination, she had warm and moist skin, a fine tremor of the fingers and hyperreflexia. Her vital signs were normal. What is the likely diagnosis?

      Your Answer: Hyperthyroidism

      Explanation:

      Excess of circulating free thyroid hormones (thyroxine and/or triiodothyronine) leads to hyperthyroidism. Common causes include Graves’ disease, toxic thyroid adenoma and toxic multinodular goitre. Grave’s disease is the most common cause and is responsible for 70-80% cases of hyperthyroidism. Other causes include excess intake of thyroid hormone, amiodarone-related. It is important that hyperthyroidism is not confused with hyperthyroxinaemia (high levels of thyroid hormone in blood), which includes causes like thyroiditis. Both the conditions lead to thyrotoxicosis (symptoms due to hyperthyroxinemia). Symptoms include weight loss associated with increased appetite, anxiety, weakness, heat intolerance, depression, increased sweating, dyspnoea, loss of libido, diarrhoea, palpitations and occasionally arrhythmias. If there is an acute increase in metabolic rate, the condition is known as ‘thyroid storm’. Elderly sometimes present only with fatigue and weight loss and this is called apathetic hyperthyroidism. Neurological symptoms are also seen in hyperthyroidism and these are tremor, chorea, myopathy and periodic paralysis. One of the most serious complications of hyperthyroidism is stroke of cardioembolic origin due to coexisting atrial fibrillation.

    • This question is part of the following fields:

      • Endocrine
      • Pathology
      162.7
      Seconds
  • Question 8 - Calculate the stroke volume in a patient admitted for coronary bypass surgery, with...

    Correct

    • Calculate the stroke volume in a patient admitted for coronary bypass surgery, with the following parameters pre-operatively:

      Oxygen consumption = 300 ml/min

      Arterial oxygen content = 20 ml/100 ml blood

      Pulmonary arterial oxygen content = 15 ml/100 ml blood and Heart rate = 100 beats/min.

      Your Answer: 60 ml

      Explanation:

      By Fick’s principle, cardiac output can be calculated as follows: VO2 = CO × (CAO2– CVO2) where VO2= oxygen consumption, CO = cardiac output, CAO2 = arterial oxygen content and CvO2 = mixed venous oxygen content. Thus, in the given problem, 300 ml/min = CO × (20 – 15) ml/100 ml CO = 300 × 100/5 ml/min CO = 6000 ml/min. Also, cardiac output = stroke volume × heart rate. Thus, 6000 ml/min = stroke volume × 100 beats/min. Hence, stroke volume = 6000/100 ml/min which is 60 ml/min.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      219
      Seconds
  • Question 9 - A significantly elevated white cell count of 50 x 109/l with 5% blasts...

    Incorrect

    • A significantly elevated white cell count of 50 x 109/l with 5% blasts and raised leucocyte alkaline phosphatase is seen in which of the following conditions?

      Your Answer: Acute myelogenous leukaemia

      Correct Answer: Leukaemoid reaction

      Explanation:

      Non-neoplastic proliferation of leucocytes causes an increase in leukocyte alkaline phosphatase (LAP). This is referred to as ‘leukemoid reaction’ because of the similarity to leukaemia with an increased white cell count (>50 × 109/l) with immature forms. Causes of leukemoid reaction includes haemorrhage, drugs (glucocorticoids, all-trans retinoic acid etc), infections such as tuberculosis and pertussis, and as a paraneoplastic phenomenon. Leukemoid reaction can also be seen in infancy as a feature of trisomy 21. This is usually a benign condition, but can be a response to a disease state. Differential diagnosis include chronic myelogenous leukaemia (CML).

    • This question is part of the following fields:

      • Haematology
      • Pathology
      93.7
      Seconds
  • Question 10 - A 45-year old gentleman presented to the emergency department at 5.00 AM with...

    Correct

    • A 45-year old gentleman presented to the emergency department at 5.00 AM with pain in his left flank. The pain began suddenly and presented in waves throughout the night. Urine examination was normal except for presence of blood and few white blood cells. The pH and specific gravity of the urine were also found to be within normal range. What is the likely diagnosis?

      Your Answer: Ureteric calculus

      Explanation:

      A calculus in the ureter, if less than 5mm in diameter is likely to pass spontaneously. However, a larger calculus irritates the ureter and may become lodged, leading to hydroureter and/or hydronephrosis. Likely sites where the calculus might get lodged, include pelviureteric junction, distal ureter at the level of iliac vessels and the vesicoureteric junction. An obstruction can result in reduced glomerular filtration. There can be deterioration in renal function due to hydronephrosis and a raised glomerular pressure, leading to poor renal blood flow. Permanent renal dysfunction usually takes about 4 weeks to occur. Secondary infection can also occur in chronic obstruction.

    • This question is part of the following fields:

      • Pathology
      • Renal
      321.9
      Seconds
  • Question 11 - A 50-year old, obese gentleman with a compression fracture of T11 vertebra was...

    Incorrect

    • A 50-year old, obese gentleman with a compression fracture of T11 vertebra was admitted in the hospital. Examination revealed a raised blood pressure 165/112 mmHg and blood glucose 8.5 mmol/l. His abdomen had the presence of purplish striae. What condition is he likely to be suffering from?

      Your Answer: Pheochromocytoma

      Correct Answer: Adrenal cortical carcinoma

      Explanation:

      Adrenocortical carcinomas are rare tumours with reported incidence being only two in a million. However, they have a poor prognosis. These are large tumours and range from 4-10 cm in diameter. They arise from the adrenal cortex and 10% cases are bilateral. 50-80% are known to be functional, leading to Cushing syndrome. Even though the tumour affects both sexes equally, functional tumours are slightly commoner in women and non-functional tumours are commoner in men. As compared to women, men also develop this tumour at an older age and seem to have a poorer prognosis.

    • This question is part of the following fields:

      • Endocrine
      • Pathology
      89.3
      Seconds
  • Question 12 - Which of the following physiological changes will you see in a young man...

    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: Decreased myoglobin

      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
      20.4
      Seconds
  • Question 13 - A new-born was found to have an undeveloped spiral septum in the heart....

    Incorrect

    • A new-born was found to have an undeveloped spiral septum in the heart. This is characteristic of which of the following?

      Your Answer: Atrioventricular septal defect

      Correct Answer: Persistent truncus arteriosus

      Explanation:

      Persistent truncus arteriosus is a congenital heart disease that occurs when the primitive truncus does not divide into the pulmonary artery and aorta, resulting in a single arterial trunk. The spiral septum is created by fusion of a truncal septum and the aorticopulmonary spiral septum. Incomplete development of these septa results in incomplete separation of the common tube of the truncus arteriosus and the aorticopulmonary trunk.

    • This question is part of the following fields:

      • Cardiovascular
      • Pathology
      27.5
      Seconds
  • Question 14 - A 35-year old lady presents to her GP with vague abdominal symptoms. Examination...

    Incorrect

    • A 35-year old lady presents to her GP with vague abdominal symptoms. Examination reveals a normal size spleen. Which of the following is the likely diagnosis?

      Your Answer: Sickle cell anaemia

      Correct Answer: Idiopathic thrombocytopenic purpura

      Explanation:

      Idiopathic thrombocytopenic purpura (ITP) is a disease caused due to development of an antibody against a platelet antigen (autoantibody). In childhood disease, the autoantibody gets triggered by binding of viral antigen to the megakaryocytes. Presentation includes unexplained thrombocytopenia, petechiae and bleeding from mucosal surfaces. The spleen usually does not enlarge in size. However, splenomegaly can occur due to coexisting viral infection. Marrow examination reveals normal or increased number of megakaryocytes. Diagnosis is by exclusion of other thrombocytopenic disorders.

    • This question is part of the following fields:

      • Haematology
      • Pathology
      53.6
      Seconds
  • Question 15 - The periphery of a haematoma is infiltrated by fibroblasts, collagen and new vasculature....

    Correct

    • The periphery of a haematoma is infiltrated by fibroblasts, collagen and new vasculature. This process is best described as?

      Your Answer: Organisation of the haematoma

      Explanation:

      Formation of granulation tissue at the periphery of the hematoma is a normal process leading to resolution. This granulation tissue is composed of new capillaries, fibroblasts and collagen. Lysis of a blood clot can occur, but the actual process of this response is known as organization, wherein the scar tissue will become part of the vessels. This is followed by recanalization and embolization which can lead to eventual complications. Proliferation of a clot will occur due to an imbalance in the clotting and lysing systems. Thrombosis has nothing to do with the process described above.

    • This question is part of the following fields:

      • Cell Injury & Wound Healing
      • Pathology
      42.4
      Seconds
  • Question 16 - A 38-year old woman presents to the clinic with a 2 cm eczema-like...

    Correct

    • A 38-year old woman presents to the clinic with a 2 cm eczema-like lesion on the areolar region of her left breast, for 5 months. Biopsy of the lesion showed large cells at the dermal-epidermal junction with positive staining for mucin. What is the likely diagnosis?

      Your Answer: Paget’s disease of the breast

      Explanation:

      Paget’s disease of the breast or nipple resembles eczema in appearance with an underlying carcinoma typically. The disease is usually unilateral and presents with inflammation, oozing and crusting along with a non-healing ulcer. Treatment is often delayed due to the innocuous appearance but can be fatal. It results due to spread of neoplastic cells from the ducts of the mammary gland to the epithelium.

    • This question is part of the following fields:

      • Pathology
      • Women's Health
      51.5
      Seconds
  • Question 17 - A 24-year old, lactating mother presents to the clinic with a tender, 1.5cm...

    Incorrect

    • 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: Fibroadenoma

      Correct 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.

    • This question is part of the following fields:

      • Pathology
      • Women's Health
      31.6
      Seconds
  • Question 18 - What percentage of the cardiac output is delivered to the brain? ...

    Correct

    • What percentage of the cardiac output is delivered to the brain?

      Your Answer: 15%

      Explanation:

      Among all body organs, the brain is most susceptible to ischaemia. Comprising of only 2.5% of total body weight, the brain receives 15% of the cardiac output. Oxygen extraction is also higher with venous oxygen levels approximating 13 vol%, and arteriovenous oxygen difference of 7 vol%.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      10.4
      Seconds
  • Question 19 - Langhans giant cells are characteristically seen in which type of inflammation? ...

    Correct

    • Langhans giant cells are characteristically seen in which type of inflammation?

      Your Answer: Granulomatous inflammation

      Explanation:

      Langhans giant cells are characteristically seen in granulomatous inflammation. They form when epithelioid cells fuse together. They usually contain a nuclei with a horseshoe-shaped pattern in the periphery of the cell.

    • This question is part of the following fields:

      • Inflammation & Immunology
      • Pathology
      27
      Seconds
  • Question 20 - What is the normal duration of PR interval on an electrocardiogram of a...

    Incorrect

    • What is the normal duration of PR interval on an electrocardiogram of a healthy individual?

      Your Answer: 0.01 0 0.10 s

      Correct Answer: 0.12–0.20 s

      Explanation:

      PR interval extends from the beginning of the P-wave until the beginning of the QRS complex. The normal duration of the PR interval is 0.12-0.20 s. It can be prolonged in first degree heart block, and reduced in Wolff-Parkinson-White syndrome.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      52.9
      Seconds
  • Question 21 - The patient who is diagnosed with bladder cancer asked his physician, what could...

    Correct

    • The patient who is diagnosed with bladder cancer asked his physician, what could have been the contributing factor in the development of his bladder cancer?

      Your Answer: Smoking

      Explanation:

      Tobacco smoking is the main known contributor to urinary bladder cancer. In most populations, smoking is associated with over half of bladder cancer cases in men and one-third of cases among women.

    • This question is part of the following fields:

      • Neoplasia
      • Pathology
      23.2
      Seconds
  • Question 22 - Which of the following morphological characteristic is a salient feature of a pure...

    Incorrect

    • Which of the following morphological characteristic is a salient feature of a pure apoptotic cell?

      Your Answer: Nuclear stabilisation

      Correct Answer: Chromatin condensation

      Explanation:

      Apoptosis is the programmed death of cells which occurs as a normal and controlled part of an organism’s growth or development. The changes which occur in this process include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, chromosomal DNA fragmentation, and global mRNA decay. The cell membrane however remains intact and the dead cells are phagocytosed prior to any content leakage and thus inflammatory response.

    • This question is part of the following fields:

      • Cell Injury & Wound Healing
      • Pathology
      53.3
      Seconds
  • Question 23 - A 4-year-old child was brought to a paediatrician for consult due to a...

    Incorrect

    • A 4-year-old child was brought to a paediatrician for consult due to a palpable mass in his abdomen. The child has poor appetite and regularly complains of abdominal pain. The child was worked up and diagnosed with a tumour. What is the most likely diagnosis ?

      Your Answer: Gastrointestinal Stromal Tumour

      Correct Answer: Nephroblastoma

      Explanation:

      Nephroblastoma is also known as Wilms’ tumour. It is a cancer of the kidneys that typically occurs in children. The median age of diagnose is approximately 3.5 years. With the current treatment, approximately 80-90% of children with Wilms’ tumour survive.

    • This question is part of the following fields:

      • Neoplasia
      • Pathology
      43.9
      Seconds
  • Question 24 - A 34-year-old Asian male presents with cervical lymphadenopathy. The patient is suspected to...

    Correct

    • A 34-year-old Asian male presents with cervical lymphadenopathy. The patient is suspected to have tuberculous lymphadenopathy. Excision biopsy of one of the nodes showed granulomatous inflammation. Which histopathologic feature is most likely consistent with the diagnosis of tuberculosis?

      Your Answer: Caseation necrosis

      Explanation:

      The granulomas of tuberculosis tend to contain necrosis (caseating tubercles), but non-necrotizing granulomas may also be present. Multinucleated giant cells with nuclei arranged like a horseshoe (Langhans giant cells) and foreign body giant cells are often present, but are not specific for tuberculosis. A definitive diagnosis of tuberculosis requires identification of the causative organism by microbiological cultures.

    • This question is part of the following fields:

      • Microbiology
      • Pathology
      56.1
      Seconds
  • Question 25 - A 55 year-old construction worker is diagnosed with malignant mesothelioma. Exposure to which...

    Incorrect

    • A 55 year-old construction worker is diagnosed with malignant mesothelioma. Exposure to which substance increased his risk in developing mesothelioma?

      Your Answer: Nitrogen dioxide

      Correct Answer: Asbestos

      Explanation:

      Mesothelioma is a rare, aggressive form of cancer that develops in the lining of the lungs, abdomen or heart. It is linked to inhalation of asbestos commonly used in ship building and the insulation industry. It has no known cure and has a very poor prognosis.

    • This question is part of the following fields:

      • Neoplasia
      • Pathology
      32.6
      Seconds
  • Question 26 - An alcoholic patient was found to have hypomagnesaemia on blood tests. Which of...

    Incorrect

    • An alcoholic patient was found to have hypomagnesaemia on blood tests. Which of the following clinical features will have prompted the doctor to check the serum magnesium level in this patient?

      Your Answer: Vomiting

      Correct Answer: Seizures

      Explanation:

      Hypomagnesaemia is a condition characterised by a low level of magnesium in the blood. The normal range for serum magnesium level is 0.75-1.05 mmol/l. In hypomagnesaemia serum levels of magnesium are less than 0.75 mmol/l. The cardiovascular and nervous systems are the most commonly affected. Neuromuscular manifestations include symptoms like tremor, tetany, weakness, apathy, delirium, a positive Chvostek and Trousseau sign, nystagmus and seizures. Cardiovascular manifestations include electrocardiographic abnormalities and arrhythmias e.g. ventricular fibrillation.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Pathology
      36.7
      Seconds
  • Question 27 - Difficulty in retracting the foreskin of the penis in an uncircumcised male is...

    Correct

    • Difficulty in retracting the foreskin of the penis in an uncircumcised male is known as:

      Your Answer: Phimosis

      Explanation:

      Phimosis is the inability to fully retract the foreskin of the penis in an uncircumcised male. It can be physiological in infancy, in which it could be referred to as ‘developmental non-retractility of the foreskin. However, it is almost always pathological in older children and men. Causes include chronic inflammation (e.g. balanoposthitis), multiple catheterisations, or forceful foreskin retraction. One of the causes is chronic balanitis xerotica obliterans. It leads to development of a ring of indurated tissue near the tip of the prepuce, which prevents retraction. Contributory factors include infections, hormonal and inflammatory factors. The recommended treatment includes circumcision.

    • This question is part of the following fields:

      • Pathology
      • Urology
      36.6
      Seconds
  • Question 28 - A 58-year-old woman has had a headache, fever, lethargy and nausea for the...

    Incorrect

    • A 58-year-old woman has had a headache, fever, lethargy and nausea for the last 10 days. He undergoes a CT scan which reveals a lesion in his frontal lobe, which, after a biopsy, is found to be formed by granulation tissue with collagenisation, gliosis and oedema. What's the most likely diagnosis?

      Your Answer: Progressive multifocal leukoencephalopathy

      Correct Answer: Chronic brain 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. In a CT scan, an abscess appears as an oedematous mass with ring enhancement.

    • This question is part of the following fields:

      • Neurology
      • Pathology
      49
      Seconds
  • Question 29 - Etoposide is a chemotherapeutic agent used in the treatment of different types of...

    Incorrect

    • Etoposide is a chemotherapeutic agent used in the treatment of different types of cancer. Which of the following is the correct indication for this drug?

      Your Answer: Hairy cell leukaemia

      Correct Answer: Lung cancer

      Explanation:

      Etoposide phosphate is an inhibitor of the enzyme topoisomerase II. It is used as a form of chemotherapy for malignancies such as lung cancer, testicular cancer, lymphoma, non-lymphocytic leukaemia and glioblastoma multiforme. Side effects are very common and can include low blood cell counts, vomiting, loss of appetite, diarrhoea, hair loss, and fever.

    • This question is part of the following fields:

      • Pathology
      • Pharmacology
      38.9
      Seconds
  • Question 30 - The anatomical dead space in a patient with low oxygen saturation, is 125...

    Correct

    • The anatomical dead space in a patient with low oxygen saturation, is 125 ml, with a tidal volume of 500 ml and pa(CO2) of 40 mm Hg. The dead space was determined by Fowler's method. If we assume that the patient's lungs are healthy, what will his mixed expired CO2 tension [pE(CO2)] be?

      Your Answer: 30 mmHg

      Explanation:

      According to Bohr’s equation, VD/VT = (pA(CO2) − pE(CO2))/pA(CO2), where pE(CO2) is mixed expired CO2 and pA(CO2) is alveolar CO2pressure. Normally, the pa(CO2) is virtually identical to pA(CO2). Thus, VD/VT = (pa(CO2)) − pE(CO2)/pa(CO2). By Fowler’s method, VD/VT= 0.25. In the given problem, (pa(CO2) − pE(CO2)/pa(CO2) = (40 − pE(CO2)/40 = 0.25. Thus, pE(CO2) = 30 mmHg. If there is a great perfusion/ventilation inequality, pE(CO2) could be significantly lower than 30 mm Hg, and the patient’s physiological dead space would exceed the anatomical dead space.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      46.7
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (2/7) 29%
Physiology (3/8) 38%
Inflammation & Immunology (1/2) 50%
Pathology (10/22) 45%
Renal (2/2) 100%
Orthopaedics (1/1) 100%
Endocrine (1/2) 50%
Haematology (0/2) 0%
Respiratory (1/2) 50%
Cell Injury & Wound Healing (1/2) 50%
Women's Health (1/2) 50%
Neoplasia (1/3) 33%
Microbiology (1/1) 100%
Fluids & Electrolytes (0/1) 0%
Urology (1/1) 100%
Neurology (0/1) 0%
Pharmacology (0/1) 0%
Passmed