USMLE Physiology 3

Question 1

A patient with chronic kidney disease has metabolic acidosis, hyperphosphatemia, and hypocalcemia. What secondary complication develops due to low 1,25-dihydroxyvitamin D3?

Accepted Answer

Secondary hyperparathyroidism

Answer

Primary hyperparathyroidism

Answer

Hypoparathyroidism

Answer

Pseudohypoparathyroidism

Question 2

Which hormone directly stimulates osteoclast activity and increases serum calcium and phosphate reabsorption in the kidney?

Accepted Answer

PTH (increases calcium, decreases phosphate reabsorption)

Answer

Calcitonin

Answer

1,25-dihydroxyvitamin D3

Answer

PTHrP

Question 3

In the autonomic nervous system, which receptor mediates bradycardia when stimulated by the vagus nerve?

Accepted Answer

Muscarinic M2 receptor

Answer

Nicotinic receptor

Answer

Beta-1 adrenergic receptor

Answer

Alpha-1 adrenergic receptor

Question 4

A patient has a Cushing reflex (hypertension, bradycardia, and irregular respirations). What does this indicate?

Accepted Answer

Increased intracranial pressure threatening brainstem herniation

Answer

Normal physiological response to exercise

Answer

Autonomic dysreflexia

Answer

Neurogenic shock

Question 5

Which change in pulmonary vascular resistance occurs during lung hyperinflation in emphysema?

Accepted Answer

Increased pulmonary vascular resistance leading to cor pulmonale

Answer

Decreased pulmonary vascular resistance

Answer

No change in pulmonary vascular resistance

Answer

Increased pulmonary capillary wedge pressure

Question 6

Erythropoietin (EPO) is produced primarily by which cell type in response to hypoxia?

Accepted Answer

Peritubular fibroblasts of the renal cortex

Answer

Glomerular mesangial cells

Answer

Proximal tubular epithelial cells

Answer

Juxtaglomerular cells