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  NURS 6501: MIDTERM EXAM: Please contact Your Favorite Professor for help with NURS 6501: Midterm Exam or any other assignment. Email: professorrobertphd@gmail.com   A patient with normal renal function experiences a sudden decrease in the flow through the renal tubules. Which response will occur to normalize glomerular filtration rate (GFR)? Group of answer choices
  • Increased renin release leading to efferent arteriole constriction
  • Increased renin release leading to afferent arteriole dilation
  • Decreased renin release leading to afferent arteriole constriction
  • Decreased renin release leading to efferent arteriole dilation
  The correct answer is Increased renin release leading to efferent arteriole constriction. Explanation: When there is a sudden decrease in renal blood flow (for example, due to a drop in blood pressure), the kidneys sense this change, and one of the mechanisms they use to maintain a stable glomerular filtration rate (GFR) is the renin-angiotensin-aldosterone system (RAAS).
  • Increased renin release occurs in response to decreased renal blood flow, especially in the afferent arteriole. This stimulates the release of angiotensin II, which acts to constrict the efferent arteriole.
  • Constriction of the efferent arteriole increases pressure in the glomerulus, thereby helping to maintain the glomerular filtration rate (GFR) despite the reduced renal blood flow.
  • The afferent arteriole is typically dilated to increase blood flow into the glomerulus, but the most significant effect of RAAS activation to normalize GFR is the constriction of the efferent arteriole.
Thus, the correct response is increased renin release leading to efferent arteriole constriction.