Circulatory System

Blood vessels Arteries, capillaries, veins are tube-like in construction They transport blood to and from the heart and then to various body tissues

Blood vessels Arteries –Thick-walled muscular and elastic tubes that carry oxygenated blood from heart to capillaries –Largest artery is the aorta

Blood vessels Capillaries –Minute, thin-walled vessels that connect smaller arteries to veins –Provide tissues with nourishment and elimination of waste products

Blood vessels Veins –Thin-walled blood vessels –Less elastic than arteries –Contain cup-like valves to prevent back flow, and carry blood containing waste products from capillaries back to heart –Located closer to outer surface off body than arteries

The Blood Nutritive fluid circulating through the circulatory system Approximately 80% water Composed of red and white corpuscles, platelets, plasma and hemoglobin

The Blood Sticky, salty fluid Normal temperature of 98.6 degrees F Makes up 1/20 of body weight About 8-10 pints fill adult vessels Bright red in arteries Dark red in veins (except pulmonary)

Blood Composition Red Corpuscles (red blood cells) –Also known as erythrocytes –Produced in red bone marrow –Contain hemoglobin (a complex iron protein that gives the blood its bright red color) –Carry oxygen to cells

Blood Composition White Corpuscles (white blood cells) –Also called leucocytes –Destroy disease-causing germs Blood Platelets –Smaller than red blood cells –Important to clotting Plasma –Fluid part of the blood –Straw-like in color –About 90% water and contains proteins, sugar and oxygen –Carries food and secretions to cells and carbon dioxide from cells

Chief functions of Blood Carries water, oxygen, food, secretions to cells Carries away carbon dioxide and waste –To be eliminated through lungs, skin, kidneys and large intestine Helps equalize body temperature Protects from harmful bacteria and infections –Through white blood cells Clotting –Which closes injured minute blood vessels and prevents excessive blood loss