The structure that controls urine release from the bladder is the:

Correct Answer: B

Rationale: Sphincters (internal involuntary, external voluntary) control release not ureter, loop, or duct (kidney). This defines continence mechanism, key for micturition, contrasting with renal structures.

Correct Answer: A

Rationale: DCT is ~5 mm long not 14 mm; other traits (diameter, portions, microvilli, mitochondria) are correct. This corrects DCT length, key for nephron mapping, contrasting with true histological features.

Correct Answer: C

Rationale: Macula densa is in DCT, tall/dark cells, has a basement membrane not near urinary pole (vascular pole). This corrects position, key for JGA function, contrasting with pole error.

Correct Answer: B

Rationale: Fossa navicularis (distal urethra) has stratified squamous epithelium not transitional (bladder), pseudostratified, or stratified columnar. This defines urethral lining, critical for histology, contrasting with proximal urethra.

Correct Answer: D

Rationale: Bladder has transitional epithelium, three muscle layers, and partial peritoneum not stratified columnar, two layers, or adventitia only. This corrects bladder anatomy, critical for histology, contrasting with listed errors.