Blood plasma Plasma also serves as the protein reserve of the human body. It plays a vital role in an intravascular osmotic effect that keeps electrolyte concentration balanced and protects the body from infection and other blood disorders. Blood plasma is separated from the blood by spinning a tube of fresh blood containing an anticoagulant in a centrifuge until the blood cells fall to the bottom of the tube. The blood plasma is then poured or drawn off. Blood plasma has a density of approximately 1025 kg/m, or 1.025 g/ml. Blood serum is blood plasma without clotting factors. Plasmapheresis is a medical
Sweat test sodium chloride (salt). Secretion entails the movement of salt and water from sweat gland cells into the sweat duct. Reabsorption occurs in the duct with the movement of salt from the sweat back into sweat duct cells. What remains is sweat, a salt solution with a relatively finely tuned concentration of sodium and chloride. For normal salt reabsorption to occur, individual ions of sodium and chloride must be taken from the sweat and moved back into cells of the sweat duct. These ions are moved by transporters called ion channels. In the case of sodium, there is a sodium channel;