The entrance into the kidney is called the

Correct Answer: C

Rationale: The hilum is the kidney's entry/exit point for vessels/ureter, not sinus (cavity), column (cortex), or pyramid (medulla). This defines renal gateway, vital for vascular connections, contrasting with structural terms.

Correct Answer: D

Rationale: External urethral sphincter is voluntary (skeletal muscle), unlike urethra (tube), detrusor (involuntary), or internal sphincter (smooth). This identifies micturition control, vital for continence, contrasting with involuntary structures.

Correct Answer: D

Rationale: Descending limb fluid becomes hypertonic as water exits into concentrated medullary interstitium, not isotonic/hypotonic. This describes countercurrent effect, vital for urine concentration, contrasting with initial states.

Correct Answer: C

Rationale: Capillary hydrostatic pressure (glomerulus) drives filtration, not filtrate pressure (opposes) or osmotic (retains). This identifies filtration force, key for GFR, contrasting with opposing pressures.

Correct Answer: D

Rationale: Urinary system regulates pH, pressure, volume not perspiration (skin). This excludes non-renal function, key for system roles, contrasting with sweat glands.