- Blood consists of plasma and formed elements. Plasma, which makes up about 55% of blood, is the straw-colored clear liquid in which cellular elements and dissolved substances (solutes) are suspended.
- (Serum is the fluid portion of the blood that remains after fibrin and the formed elements have been removed with centrifugation.) Plasma is approximately 92% water and 8% a mixture of both organic and inorganic substances.
The components of plasma and their functions.
- WATER (92%): Carries formed elements and dissolved substances; absorbs heat.
- Major proteins: Albumin controls water movement across membranes; affects blood viscosity (thickness), pressure, and volume; transports substances such as drugs. Globulin forms antibodies to fight bacteria and viruses. Fibrinogen forms fibrin and, with platelets, coagulates blood.
- Nonprotein nitrogen: Products of metabolism: urea, uric add, creatine, creatinine, ammonium salts; toxic if not removed; carried in blood to organs of excretion.
- Products of digestion: Amino acids, glucose, fatty adds – all needed by cells for energy, repair, and reproduction
- Regulatory substances: Enzymes for cellular chemical reactions; hormones to regulate growth and development.
- Electrolytes: Sodium (Na+), potassium (K+), calcium (Ca++), magnesium (Mg+), chloride (Cl–), phosphate (PO4–), sulfate (SO4–), bicarbonate (HCO3–), and inorganic salts.
Components of Blood
