What is the correct sequence of events in bicarbonate buffering?

Correct Answer: C

Rationale: H binds HCO₃⁻ first forms H₂CO₃, then splits to CO₂/H₂O (e.g., buffering sequence). H₂CO₃ to CO₂ is second not initial. HCO₃⁻ to H₂CO₃ reverses H drives. All in order missequences false. Binding start distinguishes it, critical for buffer mechanics, unlike subsequent or reversed steps.

Correct Answer: B

Rationale: The loop of Henle concentrates urine via water (descending) and Na+ (ascending) reabsorption not filtration (glomerulus), hormones (endocrine), or digestion (gut). This defines its role, key for osmolarity, contrasting with other functions.

Correct Answer: A

Rationale: UTIs are bacterial (E. coli common) not viral, fungal (rare), or dietary. This identifies primary cause, key for treatment, contrasting with less common etiologies.

Correct Answer: A

Rationale: Aldosterone retains Na+, raising BP not insulin (glucose), thyroxine (metabolism), or oxytocin (labor). This specifies RAAS role, key for volume control, contrasting with unrelated hormones.

Correct Answer: D

Rationale: Podocytes have secondary processes (pedicels) contacting the basal lamina, form the visceral layer, and contain actin microfilaments all true. This comprehensively describes podocytes, key for filtration slits, contrasting with partial descriptions.