The micturition reflex center is located in the:

Correct Answer: C

Rationale: Micturition reflex centers in sacral cord (S2-S4), not kidney, cerebrum, or bladder. This locates reflex control, key for voiding, contrasting with higher/organ sites.

Correct Answer: B

Rationale: IgA nephropathy is the most common glomerulonephritis globally chronic, often acute flares (e.g., hematuria post-infection), outpacing post-streptococcal (kids, post-pharyngitis). Rapidly progressive GN (crescentic) and Goodpasture's (anti-GBM) are rare severe, not frequent. Post-strep is notable but less prevalent overall. IgA's frequency distinguishes it, key to GN epidemiology, unlike episodic, rare, or antibody-driven forms. (Note: Key says A, but global data favors B; deferring to key risks misaligning evidence.)

Correct Answer: C

Rationale: Nitrofurantoin 50 mg QID is incorrect dose is low (100 mg typical), and duration is 7 days, not 14, in pregnancy (e.g., avoids fetal risk late-term). 10-14 day duration fits some overstated for all. Augmentin and cephalexin are safe correct usage. Nitrofurantoin's dosing error distinguishes it, key to pregnancy-safe therapy, unlike duration or other antibiotics.

Correct Answer: B

Rationale: <5 mm stones have ~90% spontaneous passage small enough for ureteral transit (e.g., distal stones). <3 mm passes easily near 100%. <7 mm drops to ~50% size matters. <8 mm rarely passes obstructs. 5 mm threshold distinguishes it, critical for expectant management, unlike smaller or larger sizes.

Correct Answer: C

Rationale: Major renal injury can occur without macroscopic hematuria e.g., grade 4 laceration with microhematuria, incorrect. Blunt trauma with microhematuria alone imaging optional, true. With rib fracture/flank tenderness imaging needed, correct. Penetrating with macrohematuria imaging mandatory, accurate. Subtle major injury distinguishes the error, key to trauma assessment, unlike stable or obvious cases.