Chapter 11The Cardiovascular System: Blood Anatomy & Physiology
“The living body is in constant communication with it’s external environment. Nutrients are absorbed through the lining of the digestive tract, gases move across the epithelium of the lungs, and wastes are excreted in the feces and urine. Even though these chemical exchanges occur at specialized sties, they affect every cell, tissue, and organ in a matter of moments because all parts of the body are linked by the cardiovascular system, an internal transport network.” (p. 365) Chapter 11The Cardiovascular System: Blood
Objective 6 • Categorize the various white blood cells on the basis of their structures and functions.
White Blood Cells • WBC’s are also known as leukocytes • Recognized and distinguished from RBC’s by • Larger size • Presence of a nucleus • Presence of other organelles • Lack hemoglobin • Help defend the body by • Removing pathogens, toxins, and waste • Removing abnormal or damaged cells • Capable of amoeboid movement (crawl) • Migrate out of bloodstream • Called diapedesis
Categories of WBC’s • Granulocytes • Contain abundant number of stained granules • neutrophils, eosinophils, & basophils • Agranulocytes • Have very few, if any, stained granules • monocytes & lymphocytes
Granulocyte: Neutrophil • Nucleus is contorted into 2-5 lobes • Phagocytic • First to arrive at injury • Specialize in eating bacteria • 50-70% of WBC’s After eating 1-2 dozen bacteria, they dies and burst open. Their “insides” attract more neutrophils to the site. Dead neutrophils and cell debris form pus.
Granulocyte: Eosinophil • 2-lobed nucleus • Attack object coated with antibodies • They like parasites and responding to allergic reactions • 2-4% of WBC’s
Granulocyte: Basophil • Filled with numerous granules • Rare – less than 1% of WBC’s • Attracted to tissue damage where they: • Release heparin • Prevents blood clotting • Release histamine • Enhances inflammation started by mast cells
Agranulocyte: Monocyte • Very large oval or kidney bean shaped nucleus • Migrate through tissues • Called macrophages • phagocytic • Very large, 2x bigger than RBC’s • 2-8% of WBC’s
Agranulocyte: Lymphocyte • Almost completely filled by large round nucleus • Migrate between blood and tissues • Attack foreign cells • Secrete antibodies • 20-30% of WBC’s
Changes in WBC Abundance • Leukopenia – indicates reduced numbers of WBC’s • Leukocytosis – refers to excessive numbers of WBC’s • May indicate leukemia, a cancer of blood-forming tissue • Sometimes indicated by abnormal or immature WBC’s • Can make skin look white and blood gray-ish in appearance • from SO MANY white blood cells….