Name the following:
$A$ loop of capillary running parallel to the Henle's loop.

(VASA RECTA) loop of capillary that runs parallel to the Henle's loop is known as the $Vasa$ $recta$.
The $Vasa$ $recta$ is a fine capillary network that arises from the efferent arteriole in juxtamedullary nephrons.
It runs parallel to the Henle's loop and plays a crucial role in the counter-current mechanism, which helps in maintaining a concentration gradient in the medullary interstitium for the concentration of urine.