Biology · Excretory Products and Their Elimination · NEET
No, but they are closely linked. NCERT says the efferent arteriole forms a capillary network around the renal tubule called the peritubular capillaries. The vasa recta is one minute vessel of THIS network that runs parallel to Henle's loop and is U-shaped. So the vasa recta is a special part of the peritubular capillary system, not a separate vessel from a different source.
From the efferent arteriole. Blood enters the glomerulus through the afferent arteriole and leaves through the efferent arteriole. The efferent arteriole then forms the peritubular capillaries, and the U-shaped vasa recta is part of that network. NEET often traps students by swapping afferent and efferent here.
The vasa recta runs parallel to the loop of Henle deep in the medulla. Cortical nephrons have a very short loop of Henle that extends only a little into the medulla, so they do not need a long vasa recta. Juxtamedullary nephrons have long loops that dip deep into the medulla and have a well-developed vasa recta. This is why the vasa recta is well-developed only in juxtamedullary nephrons.
It is U-shaped (like the letter U). It runs down and then back up alongside the loop of Henle. This U-shape and its parallel path to the loop are important for the counter current mechanism that helps make concentrated urine.
This is a special feature of the kidney. After filtration in the glomerulus, the efferent arteriole breaks up into the peritubular capillaries so that useful substances (water, glucose, salts) filtered out earlier can be reabsorbed back into the blood around the tubule. Only after this second capillary bed does the blood return toward the renal vein.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
They are a fine capillary network formed by the efferent arteriole around the renal tubule. They allow reabsorbed water and useful solutes to re-enter the blood.
The vasa recta is a minute, U-shaped vessel of the peritubular capillary network that runs parallel to the loop of Henle. It is important for the counter current mechanism.
In juxtamedullary nephrons, because they have a long loop of Henle running deep into the medulla. It is absent or highly reduced in cortical nephrons.
The efferent arteriole. After leaving the glomerulus it forms the peritubular capillaries, and the vasa recta is part of that network.
It is directly named in NCERT and links to the counter current mechanism and urine concentration, both frequently tested topics. Confusing its source (efferent vs afferent) or its nephron type is a common exam mistake.
