Renal Physiology · NEET PG Preparation Physiology
A decrease in renal arterial pressure triggers the myogenic mechanism of autoregulation. What is the immediate primary cellular event responsible for…
Practice question from Renal Physiology (NEET PG Preparation Physiology), with the correct answer and a step-by-step solution.
medium · MCQ · Q-13BFA7
A decrease in renal arterial pressure triggers the myogenic mechanism of autoregulation. What is the immediate primary cellular event responsible for this intrinsic renal response?
- A.Stretch-activated calcium channels in vascular smooth muscle cells open, causing contraction.Correct answer
- B.Macula densa cells sense increased chloride delivery and release adenosine.
- C.Renin release from juxtaglomerular cells is suppressed by cyclic AMP.
- D.Prostaglandins induce vasodilation of the efferent arteriole.
Solution
The myogenic mechanism is an intrinsic property of vascular smooth muscle. When renal arterial pressure drops, the stretch on the smooth muscle cells of the afferent arteriole decreases, causing stretch-activated cation channels to close, leading to membrane depolarization, calcium influx, and relaxation (vasodilation) to maintain GFR. Conversely, an increase in pressure causes stretch, opening stretch-activated calcium channels, leading to vasoconstriction.
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