Venous blood is dark red or crimson and flows steadily from a cut vein. The plasma is mostly water and transports many materials. The leukocytes comprise neutrophils, eosinophils, basophils, lymphocytes, and monocytes. The pH of the blood is from 7.35 to 7.45. The specific gravity of blood varies from 1.048 to 1.066, the corpuscles being heavier and plasma lighter than this.
Blood is of slightly higher specific gravity in men than in women.
Specific gravity is higher after exercise and at night. The plasma transports nutrients, waste products, hormones, carbon dioxide, and other substances, and contributes to fluid-electrolyte balance and thermal regulation. Formation Red blood cells are produced at the rate of approximately 2,400,000 each second. Since each red blood cell lives for approximately 120 days, the number of red cells remains at a level concentration. Taber's Cyclopedic Medical Dictionary, Edition 18.