Answer: A fall in glomerular filtration rate from reduced blood flow.
- A A rise in glomerular filtration rate from higher blood flow
- B No change, since arteriole diameter does not affect filtration
- C A surge of glucose being secreted directly into urine
- D A fall in glomerular filtration rate from reduced blood flow
Correct answer: D. A fall in glomerular filtration rate from reduced blood flow
Explanation: Constriction of the afferent arteriole reduces blood flow and pressure within the glomerular capillaries, lowering the glomerular filtration rate.
Filtrate flows through four functionally distinct stages of the nephron: Bowman's capsule filters blood, the PCT reabsorbs most useful substances unconditionally, the Loop of Henle builds a concentration gradient via counter-current exchange, the DCT secretes selected substances, and the collecting duct performs the final ADH-controlled water reabsorption.
Concept context
Nitrogenous waste, kidney structure, urine formation in the nephron, and hormonal regulation of excretion.
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