Onkotiska

Onkotiska refers to the oncotic pressure, also known as colloid osmotic pressure. It is a type of osmotic pressure exerted by large molecules, primarily plasma proteins like albumin, that are dissolved in a fluid. These large molecules are too big to pass through the semipermeable membranes of blood capillaries, so they tend to draw water towards them. In the context of blood, the oncotic pressure exerted by proteins in the plasma is crucial for regulating the movement of water between the blood and the interstitial fluid.

This pressure acts in opposition to the hydrostatic pressure, which is the pressure exerted by the blood itself due to the pumping action of the heart. Hydrostatic pressure tends to push fluid out of the capillaries into the surrounding tissues. Oncotic pressure, on the other hand, pulls fluid back into the capillaries. The balance between these two opposing forces, hydrostatic pressure and oncotic pressure, at the capillary level determines whether fluid moves into or out of the capillaries, a process vital for nutrient and waste exchange and maintaining fluid balance within the body. Changes in plasma protein concentration, such as those seen in liver disease or kidney disease, can significantly alter oncotic pressure and lead to fluid accumulation in tissues, a condition known as edema.