tailieunhanh - Ebook Human anatomy & physiology (9th edition): Part 2

(BQ) Part 2 book "Human anatomy & physiology" presentation of content: The lymphatic system and lymphoid organs and tissues, the respiratory system, the digestive system, the urinary system, the reproductive system, pregnancy and human development, heredity,.and other contents. | 17 Blood Overview: Blood Composition and Functions  (pp. 632–633) Components  (p. 632) Physical Characteristics and Volume  (p. 632) Functions  (pp. 632–633) Blood Plasma  (p. 633) Formed Elements  (pp. 634–646) Erythrocytes (Red Blood Cells)  (pp. 634–640) Leukocytes (White Blood Cells)  (pp. 640–645) Platelets  (pp. 645–646) Hemostasis  (pp. 646–651) Step 1: Vascular Spasm  (p. 646) Step 2: Platelet Plug Formation  (pp. 646–647) Step 3: Coagulation  (pp. 647–649) Clot Retraction and Fibrinolysis  (p. 649) Factors Limiting Clot Growth or Formation  (p. 649) Disorders of Hemostasis  (pp. 650–651) Transfusion and Blood Replacement  (pp. 651–653) Transfusing Red Blood Cells  (pp. 651–653) Restoring Blood Volume  (p. 653) Diagnostic Blood Tests  (pp. 653–654) Developmental Aspects of Blood  (p. 654) B lood is the river of life that surges within us, transporting nearly everything that must be carried from one place to another. Long before modern medicine, blood was viewed as magical—an elixir that held the mystical force of life—because when it drained from the body, life departed as well. Today, blood still has enormous importance in the practice of medicine. Clinicians examine it more often than any other tissue when trying to determine the cause of disease in their patients. In this chapter, we describe the composition and functions of this life-sustaining fluid that serves as a transport “vehicle” for the organs of the cardiovascular system (cardio 5 heart, vasc 5 blood vessels). To get started, we need a brief overview of blood circulation, which is initiated by the pumping action of the heart. Blood exits the heart via arteries, which branch repeatedly until they become tiny capillaries. By diffusing across the capillary walls, oxygen and nutrients leave the blood and enter the body tissues, and carbon dioxide and wastes move from the tissues to the bloodstream. As oxygen-deficient blood leaves the capillary beds, it flows into veins, which return it to .