2. The vasa recta is a specialized capillary that branches from the arteriole. The blood flow in the vasa recta runs to the flow of tubular filtrate within the nephron loop.

Vasa recta

Explanation:

The vasa recta is a specialized capillary that branches from the efferent arteriole; The blood flow in the vasa recta runs parallel, but in the opposite direction to the flow of tubular filtrate within the nephron loop

The vasa recta capillaries are long, hairpin-shaped blood vessels that run parallel to the loops of HenleThe hairpin turns slow the rate of blood flow, which helps maintain the osmotic gradient required for water reabsorptionAbsorbed water is returned to the circulatory system via the vasa recta, which surrounds the tips of the loops of HenleBecause the blood flow through these capillaries is very slow, any solutes that are reabsorbed into the bloodstream have time to diffuse back into the interstitial fluid, which maintains the solute concentration gradient in the medulla; this passive process is known as counter-current exchange

Spherical shaped cell might increase the surface area and decrease the volume.