Flashcards on The Loop of Henle: Structure and Function
The Loop of Henle: Structure and Function Explained
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Loop of Henle Physiology
12 cards
Card 1
Question: What is the permeability profile of the descending limb of the loop of Henle?
Answer: Water permeable and solute (salt) impermeable.
Card 2
Question: Which membrane protein in the descending limb allows water movement?
Answer: Aquaporin-1 (AQP1).
Card 3
Question: What transports are present in the thick ascending limb of the loop of Henle?
Answer: The sodium-potassium-2-chloride (Na+-K+-2Cl−) cotransporter that pumps Na+, K+, and 2 Cl− out into the medullary interstitium.
Card 4
Question: What effect does active salt transport by the ascending limb have on the surrounding medullary interstitium?
Answer: It makes the medullary interstitium very salty (increases its salinity/tonicity).
Card 5
Question: How does the osmotic difference created by the ascending limb affect the descending limb?
Answer: The salty medullary interstitium pulls water out of the descending limb into the interstitium.
Card 6
Question: What is the overall mechanism called when the descending limb loses water while the ascending limb actively pumps out salt?
Answer: The countercurrent multiplier mechanism.
Card 7
Question: What role does the vasa recta play with respect to the medullary interstitium's salt concentration?
Answer: The vasa recta functions as a countercurrent exchanger that prevents rapid removal of sodium chloride from the medullary interstitium, helping maintai
Card 8
Question: Describe how the vasa recta handles solute and water as blood flows down and then up the vessel.
Answer: As it goes down, the vasa recta picks up salt and loses water; as it turns and goes up, it loses salt and gains water, thus minimizing net loss of int
Card 9
Question: Besides maintaining the medullary gradient, what is another function of the vasa recta?
Answer: It delivers oxygen and certain nutrients to medullary tissue cells.
Card 10
Question: Why is the vasa recta's blood flow described as 'sluggish,' and what is the significance?
Answer: The vasa recta has very slow blood flow, which helps it act as an effective countercurrent exchanger to avoid washing out the medullary gradient while