The membranous urethra is lined with

Correct Answer: B

Rationale: Membranous urethra has stratified columnar epithelium not squamous (penile), transitional (bladder), or pseudostratified. This defines urethral histology, critical for anatomy, contrasting with adjacent regions.

Correct Answer: C

Rationale: Urine (filtrate) flows from the proximal convoluted tubule (PCT) into the loop of Henle not minor calyx (collecting system), distal convoluted tubule (post-loop), or papillary duct (end of collecting duct). The PCT reabsorbs most filtrate before it enters the loop for concentration, making it the correct pre-loop location. This traces nephron flow, critical for understanding urine formation, contrasting with post-loop or collecting structures.

Correct Answer: C

Rationale: The pronephric duct's caudal end opens into the cloaca not primitive/definitive urogenital sinus (later), vesicourethral canal (bladder), or coelom. The cloaca is the early common chamber, critical for pronephric regression and mesonephric transition, contrasting with later subdivisions.

Correct Answer: D

Rationale: Premature ureteric bud division causes duplex ureter (one kidney, two ureters) not hypertrophy, agenesis, cysts, or shared ureter. This reflects branching error, key for anomalies, contrasting with unrelated defects.

Correct Answer: B

Rationale: Urine from umbilicus is urachal fistula (patent allantois) not vitelline (gut), ectopia vesicae (exstrophy), or ectopic ureter/urethra. This identifies congenital leak, key for diagnosis, contrasting with other fistulae.