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
Secretory component Secretory component The secretory component is a component of immunoglobulin A (IgA). Secretory component is a proteolytic cleavage product of the polymeric immunoglobulin receptor which remains associated with dimeric IgA in sero-mucus secretions. Polymeric IgA binds to the polymeric immunoglobulin receptor on the basolateral surface of epithelial cells and is taken up into the cell via transcytosis. The receptor-IgA complex passes through the cellular compartments before being secreted on the luminal surface of the epithelial cells, still attached to the receptor. Proteolysis of the receptor occurs and the dimeric IgA molecule, along with the secretory component, are free to diffuse