BIOL 1003 Lecture Notes - Pulmonary Vein, Tunica Media, Factor V
Document Summary
Spherical nucleus and shape, very little cytoplasm. Memory cells have specific antigen receptors on the cell surface. Only white blood cells that return to blood stream after migrating to tissues. Oval, horseshoe or kidney shaped nucleus; more cytoplasm than lymphocytes. Nucleus does not stain as darkly as lymphocytes in blood smears. After leaving circulatory system, they differentiate into macrophages in connective tissues. Different functions: some engulf bacteria; others are involved with allergies and inflammation. If blood vessels are damaged a series (cascade) of enzyme-control reactions occurs to form a clot: prevents further blood loss, prevents invasion by pathogens. Clotting depends on clotting factors which are plasma enzymes. They are present as an inactive form in blood plasma. They are named with roman numerals e. g. factor v. Serotonin causes smooth muscle of the arterioles to contract / narrows blood vessels, cutting off the blood flow to damaged area. Pulmonary artery: transport deoxygenated blood from the right ventricle into lungs.