Blood levels are regulated by hormone influences on the kidneys. V. Movement of Body Fluids A. Exchange Between Plasma and Interstitial Fluid - Occurs across capillary membranes, primarily by diffusion. Intracellular fluid has a higher osmotic pressure than interstitial, but there are forces to counteract this. Fluid imbalance may lead to overhydration, water intoxication, and circulatory shock. Homeostasis of pH is maintained by buffer systems, exhalation of carbon dioxide, an kidney excretion.
Buffers work within fractions of a second.
This acts much like the carbonic acid-bicarbonate system. This is the most abundant buffer in body cells and plasma. The pH of body fluids may be adjusted by a change in the rate and depth of respirations, which usually takes from 1 to 3 minutes. Alkalosis is a blood pH above 7.45. A change in blood pH that leads to acidosis or alkalosis can be compensated to return pH to normal.