Physiology
⏱ ~3-min readAceMark Guide
What this topic is really about
The descending and ascending limbs of the loop of Henle generate a hyperosmotic medullary interstitium by counter‑current multiplication, allowing the kidney to concentrate urine. It does not filter blood (glomerulus does), nor does it secrete renin or produce ADH; those functions belong to the juxtaglomerular apparatus and the posterior pituitary, respectively.
The rapid depolarization phase of an action potential is driven by sodium influx through voltage-gated channels, followed by repolarization via potassium efflux. Calcium influx is incorrect because it primarily triggers neurotransmitter release at the synaptic terminal rather than propagating the action potential along the axon.
See the mechanism
The descending and ascending limbs of the loop of Henle generate a hyperosmotic medullary interstitium by counter‑current multiplication, allowing the kidney to concentrate urine. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.
An exam-style question, fully explained
The function of the loop of Henle is to:
- Identify what the question tests: The function of the loop of Henle is to:.
- The descending and ascending limbs of the loop of Henle generate a hyperosmotic medullary interstitium by counter‑current multiplication, allowing the kidney to concentrate urine.
- It does not filter blood (glomerulus does), nor does it secrete renin or produce ADH; those functions belong to the juxtaglomerular apparatus and the posterior pituitary, respectively.
Traps the examiner sets
- Calcium influx is incorrect because it primarily triggers neurotransmitter release at the synaptic terminal rather than propagating the action potential along the axon.
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