Promptly on leaving the glomerulus they break up into capillaries and become part of a rich plexus of vessels surrounding the cortical portions of the renal tubules.

This rete is responsible for the osmotic isolation of the inner medulla from the rest of the kidney and so permits the excretion of a hypertonic urine when circumstances require.

Blood in this plexus and returning from the inner medulla finds its way to the renal vein and the general circulation by pathways similar to those providing drainage for the rest of the cortex.

When angiotensin II levels are increased due to activation of the renin–angiotensin–aldosterone system, most of the arteries in the body experience vasoconstriction, in order to maintain adequate blood pressure.

To compensate, the efferent arterioles constrict to a greater degree than the other arteries, in response to increased levels of angiotensin II.