MBBS Physiology 2

Question 1

Which segment of the nephron is impermeable to water under all conditions?

Accepted Answer

Thick ascending loop of Henle

Answer

Proximal convoluted tubule

Answer

Thin descending loop of Henle

Answer

Collecting duct

Question 2

What is the normal pH range of arterial blood?

Accepted Answer

7.35–7.45

Answer

7.25–7.35

Answer

7.45–7.55

Answer

7.30–7.40

Question 3

Which hormone causes water reabsorption in the collecting duct by inserting aquaporin-2 channels?

Accepted Answer

Antidiuretic hormone (ADH)

Answer

Aldosterone

Answer

Atrial natriuretic peptide

Answer

Parathyroid hormone

Question 4

Which phase of the cardiac action potential is responsible for the plateau in ventricular myocytes?

Accepted Answer

Phase 2 — plateau

Answer

Phase 0 — rapid depolarization

Answer

Phase 1 — early repolarization

Answer

Phase 3 — rapid repolarization

Question 5

What is the primary stimulus for erythropoietin (EPO) secretion?

Accepted Answer

Tissue hypoxia detected by renal peritubular cells

Answer

Low hemoglobin concentration

Answer

High altitude exposure

Answer

Low serum iron

Question 6

Which of the following best describes the role of surfactant in the lungs?

Accepted Answer

Reduces surface tension to prevent alveolar collapse

Answer

Increases surface tension to stabilize alveoli

Answer

Facilitates oxygen diffusion across the alveolar membrane

Answer

Neutralizes inhaled pathogens