This binding often is required to initiate the elimination of foreign microorganisms.Īlthough the different blood cells have distinct structures and functions, they are all produced at the same site, the bone marrow, in a complex process called hematopoiesis. B cells produce and secrete antibodies that can bind to foreign antigens. T cells also kill cells displaying foreign antigens on their surface (e.g., virus-infected or transplanted cells). T cells secrete messenger substances (i.e., cytokines) that activate and regulate the immune response. Lymphocytes, which mediate and regulate the immune response, consist of two main groups: T cells and B cells. In addition, these cells display foreign proteins and other molecules (i.e., antigens) on their surface and thereby help activate the body’s immune response. Monocytes (which circulate in the blood) and macrophages (monocytes that have entered the tissues) also ingest and destroy foreign organisms and substances. Cells of the most common type are called neutrophils. Granulocytes recognize and eliminate microorganisms, especially bacteria, by ingesting them. The WBC’s are subdivided further into three groups-granulocytes, monocytes and macrophages, and lymphocytes-each with specific functions. Through several intermediate stages, these precursors differentiate further and develop into the mature cells circulating in the blood or residing in the tissues. Under the influence of certain proteins (i.e., growth factors), this stem cell multiplies and differentiates into increasingly committed precursor cells. All types of circulating blood cells develop from a pluripotent stem cell. These proteins include those involved in blood clotting as well as immune proteins (i.e., antibodies or immunoglobulins).īlood cells fall into three major categories, each of which has specific functions, as follows:īlood cell development. In addition to water, plasma contains minerals nutrients regulatory substances, such as homones gases, such as oxygen and carbon dioxide and proteins.

The blood’s most important functions include transporting substances, such as oxygen, nutrients, waste products to be excreted, and chemical messengers defending the body against foreign organisms and substances, such as bacteria, viruses, and fungi and repairing injured blood vessels.īlood cells make up about 45 percent of the blood volume the remaining 55 percent consists of a watery liquid called plasma. Blood vessels reach every organ and tissue in the body, indicating that the blood and the integrity of the blood vessels are essential to maintaining the body’s health and functioning.

Test viscosity of hemoglobin in rbc