Medical MCQs: Boards, postgrad, license exams

Physiology MCQ:
A 45-year-old man with chest pain is found to have an elevated ST segment on ECG. This segment normally corresponds to which phase of the ventricular action potential?

A. Rapid depolarization (phase 0)
B. Early repolarization (phase 1)
C. Plateau phase (phase 2)
D. Rapid repolarization (phase 3)
E. Resting membrane potential (phase 4)

Physiology MCQ:

A 60-year-old man with long-standing hypertension develops left ventricular hypertrophy. Which of the following changes occurs in his heart as a result of increased afterload?

A. Decreased wall thickness and increased chamber size

B. Increased wall thickness and decreased compliance

C. Decreased wall stress and increased compliance

D. Increased chamber radius with thin walls

E. Decreased afterload with increased ejection fraction

Physiology MCQ:

A 55-year-old man with long-standing hypertension is started on an ACE inhibitor. Two weeks later, his serum creatinine rises significantly. Ultrasound reveals bilateral renal artery stenosis.

Which of the following best explains the rise in creatinine after starting the medication?

A. Increased efferent arteriolar constriction and GFR
B. Decreased efferent arteriolar tone leading to reduced glomerular filtration pressure
C. Increased sodium reabsorption in the proximal tubule
D. Increased aldosterone secretion from the adrenal cortex
E. Decreased renal blood flow due to afferent arteriole constriction