BIOL 221 Lecture Notes - Lecture 4: Extracellular Fluid, Colloid, Nephron

• School: Towson University
• Department: Biology
• Course: BIOL 221
• Professor: Ellen Lathrop-Davis

Document Summary

Interstitial fluid hydrostatic pressure (ifp) is the physical pressure of the fluid in the interstitial space that tends to push interstitial fluid back into the capillary; that is, it opposes fluid movement into the if from the capillary. Because there is relatively less pressure in the interstitial space and because fluid is removed by the lymphatic system, ifp is normally very low, around 3 mm hg (amerman, 2019). Ifp does not normally change significantly from the arterial to the venous end of the capillary. Net hydrostatic pressure is the difference between the blood pressure (bp) and interstitial fluid hydrostatic pressure (ifp). It is calculated by subtracting interstitial fluid hydrostatic pressure (ifp) from blood pressure. At the arterial end it averages 27 mm hg; at the venous end, 7 mm hg. Osmotic pressure is the pressure needed to oppose water movement across a selectively permeable membrane.