All are true about renal circulation except
High-Yield Explanation
In a resting adult, the kidneys receive 1.2-1.3 L of blood per minute, or just under 25% of the cardiac output. When the mean systemic aerial pressure is 100 mm Hg, the glomerular capillary pressure is about 45 mm Hg. The main function of the renal coex is filtration of large volumes of blood through the glomeruli, hence, renal coical blood flow is relatively great and little oxygen is extracted from the blood. When the kidney is perfused at moderate pressures (90-220 mm Hg in the dog), the renal vascular resistance varies with the pressure so that renal blood flow is relatively constant. Autoregulation occurs by a direct contractile response to stretch of the smooth muscle of the afferent aeriole. NO may also be involved. Maintenance of a relatively constant renal blood flow and GFR is the ability of individual blood vessels to resist stretching during increased aerial pressure, a phenomenon referred to as the myogenic mechanism.