The middle layer of the urinary bladder is identified as ___________.

Correct Answer: B

Rationale: Bladder's middle layer is submucosa (connective) not mucosa (inner), muscularis (outer), or sphincter (none). This defines histology, critical for structure, contrasting with other layers.

Correct Answer: C

Rationale: Capillary hydrostatic pressure (~60 mmHg) drives filtration not filtrate (opposes), osmotic (retains), or all. This identifies filtration force, key for GFR, contrasting with opposing pressures.

Correct Answer: B

Rationale: The macula densa resides in the distal tubule within the juxtaglomerular apparatus chemoreceptors/osmoreceptors detect NaCl and osmolarity shifts, signaling renin release by juxtaglomerular cells (e.g., low NaCl triggers). The proximal tubule reabsorbs lacks this role. The Loop of Henle concentrates no renin link. The glomerulus filters unrelated. Its distal location and regulatory function distinguish it, key to tubuloglomerular feedback and blood pressure control, unlike proximal, loop, or filtration sites.

Correct Answer: C

Rationale: Net Filtration Pressure (NFP) = glomerular hydrostatic pressure (HPG) - (oncotic pressure [OPG] + capsular hydrostatic pressure [HPC]): 30 - (25 + 15) = -10 mmHg. Positive 10 mmHg ignores opposition incorrect. Zero miscalculates balance. 5 mmHg underestimates opposition. Negative NFP distinguishes it, indicating no filtration due to shock (e.g., low HPG), key to GFR collapse, unlike positive or neutral errors.

Correct Answer: C

Rationale: ADH-dependent reabsorption occurs in the medullary collecting duct ADH inserts aquaporins, reclaiming water (e.g., concentrates urine). Proximal tubule reabsorbs isotonically ADH-independent. Loop of Henle sets gradient not ADH-driven. Distal tubule starts ADH effect less medullary. Medullary site distinguishes it, key to urine concentration, unlike proximal or loop roles.