Biomedical Science practice questions

A 23-year-old man has recurrent episodes of muscle cramps during intense exercise. During an episode, plasma lactate rises from 1.2 to 1.5 mmol/L (reference 0.5…

A 54-year-old woman has progressive exertional dyspnoea. Spirometry shows a forced expiratory volume in one second of 2.4 L (reference greater than 2.0 L) and a…

A laboratory technician is found unconscious in a poorly ventilated garage. Arterial blood shows pH 7.39, PaO2 13.0 kPa (reference 10.7–13.3 kPa), and PaCO2 5.1…

A 68-year-old man develops sudden pleuritic chest pain and tachypnoea after prolonged immobility. Arterial blood gas analysis on room air shows pH 7.48, PaCO2 3…

A patient with profuse watery diarrhoea caused by enterotoxin receives an oral solution containing sodium and glucose. Before treatment, stool output is high an…

A 7-month-old infant becomes lethargic after an overnight fast during gastroenteritis. Blood glucose is 1.9 mmol/L (reference 3.5–6.0 mmol/L), beta-hydroxybutyr…

An enzyme catalyses conversion of substrate S to product P. Without inhibitor, Vmax is 120 μmol/min and the Michaelis constant is 4 mmol/L. In the presence of i…

A 35-year-old woman has palpitations and a 9 kg weight loss over 3 months. Her free thyroxine is 48 pmol/L (reference 10–22 pmol/L), TSH is less than 0.01 mIU/L…

A 41-year-old woman has progressive weight gain, proximal muscle weakness and easy bruising. Her 24-hour urinary free cortisol is 780 nmol/day (reference less t…

A 29-year-old woman has a plasma bicarbonate concentration of 15 mmol/L (reference 22–29 mmol/L) and a normal anion gap. Her urine pH is 6.2 during bicarbonate…

A healthy adult receives an intravenous glucose load. Plasma glucose is 12 mmol/L (reference 3.5–7.8 mmol/L), the measured glomerular filtration rate is 120 mL/…

A 48-year-old woman has a new holosystolic murmur and exertional dyspnoea. Echocardiography shows a regurgitant volume from the left ventricle into the left atr…