NURSING 2LA2 Lecture Notes - Lecture 5: Posterior Pituitary, Asphyxia, Turgor Pressure
6 Apr 2018
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Document Summary
Fluid balance at the level of the capillary relies on a balance between opposing forces: the pushing force of hydrostatic pressure, and the pulling force of oncotic pressure. At the arterial end of the capillary, hydrostatic pressure is higher than oncotic pressure in the capillary so uid moves- or is pushed- out into the interstitial space. Current research shows that interstitial hydrostatic pressure has a small negative value and contributes slightly to the movement of uid from the capillary to the tissue. Towards the venous end of the capillary, much of the uid has moved to the interstitial space, leaving the solutes- in particular, the plasma proteins- behind. This creates higher capillary osmotic pressure which effectively pulls uid from the interstitial space back into the vessel. Some particles such as glucose and electrolytes move form the vessel into the interstitial space and create interstitial colloidal osmotic pressure, pulling a small amount of uid into the interstitial space.
