基医专外学lood and immunity160329.pptxVIP

Blood and immunity; Blood is composed of cells, or formed elements, suspended in a clear, straw- colored fluid called plasma. The cells include erythrocytes, leukocytes, and platelets or thrombocytes (clotting cells), and constitute about 45 percent of the total blood volume. ; The remaining 55 percent of blood is plasma. 90% of plasma is water. The remaining 10% contains nutrients, electrolytes, gases, wastes, albumin, clotting factors, antibodies, enzymes, and hormones. The pH of the plasma is steady at about 7.4. ; Oxygen from the lungs and nutrients from the digestive tract are absorbed into blood for transport to the tissues. And, carbon dioxide and other waste products of cellular metabolism are absorbed from the tissues for transport to the organs of elimination. The blood also transports hormones from endocrine glands to their target organs. ;Erythrocytes.;Erythrocytes.;Erythrocytes.;Erythrocytes.;Leukocytes;They total about 5,000 to 10,000 per cubic millimeter, but their number may increase during infection. There are five different types of leukocytes: three types of granulocytes (eosinophil, basophil, and neutrophil) and two types of agranulocytes (monocyte and lymphocyte).;Granulocytes are characterized by the presence of visible particle (granules) in their cytoplasm and by their multi-lobed nuclei. Because of their oddly shaped nuclei, granulocytes are sometimes called polymorphonuclear leucocytes (PMN). The three types of granulocytes are named for the types of dye they take up in laboratory tests.;Eosinophils take up a red acidic dye called eosin; their main function is to detoxify foreign proteins, especially those causing allergic reactions.;Basophils take up alkaline dyes; their main function is to release histamines and heparin at sites of injury. ;Neutrophils take up both acidic and alkaline dyes; they are phagocytic cells, responsible for ingesting and destroying bacteria and other foreign particles.;Unlike granulocytes, agranulocytes do