reason for high hydrostatic pressure in glomrulus
 

Hydrostatic pressure is the pressure exerted by fluid on the capillary walls of the glomerulus. Hydrostatic pressure in the glomerular capillaries is essentially the blood pressure in the glomerulus.

As blood pressure in the glomerulus goes up, hydrostatic pressure in the glomerulus also goes up. This helps in an increase in glomerular filtration rate because pressure forces more blood to be filtered by the glomerulus per unit time.

The first step in the formation of urine is ultrafiltration of the blood. This takes place in the renal capsule. Ultrafiltration is the filtration under pressure. The pressure comes from the blood pressure and is known as the hydrostatic pressure or pumping pressure. The blood enters at high pressure directly from the heart via the dorsal aorta, renal artery and finally an arteriole.
Glomerular hydrostatic pressure is the pressure exerted by fluids on the walls of glomerulus. The high glomerular hydrostatic pressure forces water and solutes out from glomerulus into filtrate during ultrafiltration.

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