why is hydrostatic pressure in glomerular capillary so high?

[dakims]

why is this hydrostatic pressure as well as net filtration pressure so much higher than in capillaries of other tissues?

[mith]

efferent and afferent arterioles

[dakims]

what about it?

[mith]

well pressures from arteries are high right?

[MrMistery]

two factors:
1. what dave said(arterial vs venous blood)
2. the renal artery breaks right from the abdominal aorta. small distance from the heart => most of the pressure is still there..

[mcar]

maybe you ask for differences in pressures within blood vessels. capillaries are anatomically very thin structures and smaller components pass these vessels. larger vessels therefore have higher pressures within, since these are thicker.

[cracked_doc]

It's because the afferent arteriole is thicker then the efferent arteriole.

[dakims]

the afferent arteriole and efferent arteriole are both subject to regulation so that may be true at one time but not overall

[cracked_doc]

couldn't understand you...what do you mean by "regulation"?

[D_GILL911]

Perfusion and absorbtion are the primary purpose of the capillaries. The artery brings oxygenated blood and nutrients from the heart. The artery then breaks down into arterioles, then capillaries. Here hydrostatic pressure is increased to allow proper diffusion to take place. In the kidneys the afferent ateriole is where blood and other fluids enter the glomerolar capillaries. The hydrostatic is obviously increased at this point secondary to the fact that it just came from primary circulation. Once the blood has circulated through the kidney in then exits through the efferent arterioles. At this point hydrostatic pressure has been greatly reduced. The filtered blod then re-enters systemic circulation or is secreted into the ureters to be excreted from the body. The glomerolus is responsible mainly for reabsorbtion of protien (just FYI). When someone has extended an extended illness, leukocytes can accumulate in the glomerolus, resulting in glomerolonephritis. This can be detected by dysuria, flank pain, and increased protien output note in urine analysis. Just a little more relevant FYI. Any more questions. Just ask.