Components of Blood Circulatory System

Circulation

Types of Blood Vessels Arteries –Carry blood away from the heart –Have thick, muscular walls –Branch out into arterioles –Largest artery = Aorta

Veins (Contain valves – prevent backflow) –Carry blood back to the heart –Have thinner walls (less muscle) –Veins branch out into venules –Largest vein = Vena Cava

Capillaries –Connect arterioles to venules –Extremely thin walls (allow oxygen & carbon dioxide to pass through)

Components of Blood 1.Red blood cells (RBC) 2.White blood cells (WBC) 3.Plasma 4.Platelets (Thrombocytes)

Plasma –Made of mostly water –Transports nutrients, hormones, proteins, salts, & enzymes –Suspends solid components of blood

Types of Blood Cells Erythrocytes –RBCs –Carry oxygen to body cells / Return carbon dioxide to the lungs –Contain hemoglobin Heme = Iron compound Globin = Protein molecule

Leukocytes –WBCs –Fight infection –5 types of WBC

Thrombocytes –Known as platelets –Purpose is to clot RBC together –When a vessel is cut, platelets the site to form a sticky plug (then form scab)

Platelets

Types of WBC Neutrophils Most numerous Destroy bacteria (surround & consume = phagocytosis) Eosinophils Destroy parasites (release toxin to kill) Defends against allergic reactions

Basophils Produce histamine; participates in body’s inflammatory response Monocytes Destroy bacteria & foreign materials (dead cells) Largest type of WBC

Lymphocytes (Special type) Can multiply in tissues of tonsils, spleen, lymph nodes T-Cells (Helper T / Killer T) & B –Cells (create antibodies) T and B Cells fight viruses Protect against cancer cells

Circulation Facts About 4 to 6 quarts of blood in the average adult. Heart circulates the body’s blood supply about 1,000 times each day. At age 70, the heart has beat about 2 ½ billion times. Plasma is 90% water RBC / WBC / Platelets are made in the bone marrow