Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Juxtamedullary nephrons are specialized structures in the kidneys that play a crucial role in the concentration of urine. They have long loops of Henle that extend deep into the renal medulla, enabling efficient water reabsorption.
5 Must Know Facts For Your Next Test
Juxtamedullary nephrons constitute about 15-20% of all nephrons in human kidneys.
They are essential for producing concentrated urine by creating a high osmolarity gradient in the medulla.
The longer loops of Henle in these nephrons allow more water to be reabsorbed back into the bloodstream.
Their function is critical in maintaining body fluid balance and regulating blood pressure.
Juxtamedullary nephrons work closely with vasa recta, which help maintain the osmotic gradient necessary for water reabsorption.
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Related terms
Cortical Nephron: These are nephrons with shorter loops of Henle located primarily in the renal cortex.
Loop of Henle: A structure within each nephron that plays a key role in concentrating urine and conserving water.
Vasa Recta: A network of blood vessels surrounding juxtamedullary nephron loops that helps maintain osmotic gradients necessary for water reabsorption.