Compare the important physiological functions of the capillaries arising from the efferent arterioles of cortical nephrons to those arising from the efferent arterioles of juxtamedullary nephrons

 

The capillaries arising from the efferent arterioles of cortical nephrons are called peritubullar capillaries while those arising from the efferent arterioles of juxtamedullary nephrons are called vasa recta.

Step-by-step explanation

In other tissues, we know that arteries get to the tissue, they branch in arterioles and then get to the capillaries, however it is not like that in the kidneys. In the kidneys, the renal artery gets there and branches to give rise to the afferent arteriole that will form the glomerulus. After this, we have an efferent arteriole that will continue its way and it will form capillaries.

Peritubular capillaries are blood vessels that travel alongside the nephrons allowing the functions of REABSORPTION AND SECRETION between the blood and the tubular fluid of the nephron. So, when we talk about reabsorption of molecules such as proteins, glucose, amino acids, or secretion of hydrogen ions, potassium, we are talking about that those substances are being reabsorbed to the peritubular capillaries and being excreted from them.

The vasa recta arise from the efferent arteriole of the juxtamedullary nephrons. They are straight arterioles and straight venules of the kidney that enter the medulla as the straight arterioles and leave the medulla to ascend to the cortex as the straight venules. So, these vessels go into the medulla and are closer to the loop of Henle. Each atraight arteriole has a hairpin turn in the medulla and carries blood at a very slow rate and they are two important factors crucial in the maintenance of the countercurrent exchange that prevents washout of the concentration gradients established in the renal medulla and helps in water reabsorption and produce a concentrated urine. So, in the descending portion of the vasa recta, sodium chloride and urea are reabsorbed into the blood, while water is secreted, and on the ascending portion, sodium chloride and urea are secreted into the interstitium, while water is reabsorbed.