Concepts of Human Anatomy & Physiology   5/e   Van De Graaff/Fox
	Student   Online Learning Center

I. Functions and Components of the Circulatory System

Concept: Blood serves numerous functions, including the transport of respiratory gases, nutritive molecules, hormones, and metabolic wastes. Blood is transported through the body in a system of vessels leading from and returning to the heart.

II. Composition of the Blood

Concept: Blood consists of formed elements that are suspended and carried in a fluid called plasma. The formed elements-erythrocytes, leukocytes, and platelets-function, respectively, in oxygen transport, immune defense, and blood clotting. Plasma contains various types of proteins and many water-soluble molecules.

III. Blood Clotting

Concept: When a blood vessel is injured, a number of physiological mechanisms are activated that promote hemostasis, or the cessation of bleeding. Breakage of the endothelial lining of a vessel exposes collagen proteins from the subendothelial connective tissue to the blood. This initiates separate but overlapping hemostatic mechanisms: vasoconstriction, the formation of a platelet plug, and the production of a web of fibrin proteins around the platelet plug.

IV. Acid-Base Balance of the Blood

Concept: The pH of blood plasma is maintained within a narrow range of values through the functions of the lungs and kidneys. The lungs regulate the carbon dioxide concentration of the blood, and the kidneys regulate the bicarbonate concentration.

Copyright ©1998 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use and Privacy Policy.
McGraw-Hill Higher Education is one of the many fine businesses of The McGraw-Hill Companies.
For further information about this site contact mhhe_webmaster@mcgraw-hill.com.