By Dominique, Stephanie, Lauryn Chapter 11: 5-7 By Dominique, Stephanie, Lauryn

White Blood Cells 11-5 Circulate for only a short portion of their life-span. Travel through the loose and dense connective tissue. When an injury is detected the WBCs leave the bloodstream and immediately go to the injured area.

Types of White Blood Cells Neutrophils Eosinophils Basophils Monocytes Lymphocytes

Neutrophils 50%-70% of white blood cells A mature neutrophils has a very dense contorted nucleus with two - five lobes resembling beads on a string. These are the first white blood cells to reach an injury site. Life span of 10 hours when not activated. A mixture of dead neutrophils, cellular debris, and other waste products form the pus associated with infected wounds

Eosinophils They were named because of their granules that stain darkly with the red dye eosin Usually represents 2%-4%circulating white blood cells Similar in size to Neutrophils Attack objects coated with antibodies Numbers increase dramatically during a parasitic infection or an allergic reaction.

Basophils -Have numerous granules that stain darkly with basic dyes. In a standard blood smear the granules are purple or blue - The cells are smaller than eosinophils and neutrophils - They are relatively rare, accounting for less than 1% of the circulating white blood cell population. - Migrate to sites of injury and cross the capillary wall to accumulate within damaged tissue - The granules contain heparin which prevents blood clotting and histamine which enhances the local inflammation initiated by mast cells

Monocytes Nearly twice the size of a typical erythrocyte Normally account for 2%-8% of circulating white blood cells Remain in circulation for about 24 hours before entering peripheral tissues Active monocytes release chemicals that attract and stimulate neutrophils, additional monocytes, and other phagocytes

Lymphocytes Slightly larger than red blood cells Contain a relatively large nucleus surrounded by a thin halo of cytoplasm Account to 20%-40% of white blood cell population Antibodies of lymphocytes can attack foreign cells or proteins in distant parts of the body

Platelets 11-6 Thrombocytes The function is homeostasis They clump together and stick to vessel wall Activate an intrinsic pathway of coagulation phase Produced by megakaryocytes in red bone marrow Initiates the clotting process and helps close injured blood vessels These are found in nonmammalian vertebrate Are nucleated cells Megakaryocytes Red bone marrow containing enormous cells with large nuclei Continuously shed cytoplasm in small membrane enclosed packets These packets are the platelets that enter the bloodstream

Phases of Homeostasis 11-7 Stop bleeding and prevent blood loss Vascular phase Platelet phase Coagulation phase

Blood Clotting Process Cannot occur unless the plasma contains the necessary clotting factors which include calcium ions and 11 different plasma proteins During the coagulation phase, one protein is converted into an enzyme, activating other proteins causing a chain reaction.

Extrinsic Pathways Intrinsic Pathways Beings with the activation of protein enzymes exposed to collagen fibers at the injury site Proceeds with the assistance of a platelet factor released by aggregating platelets. Calcium ions and a single vitamin K affect almost every aspect of the blood clotting process. Inadequate amounts of vitamin K leads to breakdown of the common pathway, inactivating the clotting system. Begins the release of a lipoprotein called tissue factor by damaged endothelial cells or peripheral tissues. The greater the damage, the more tissue factor is released and the faster clotting occurs Common Pathways Begins when enzymes from either the extrinsic or the intrinsic pathway activate factor X, forming the enzyme prothrombinase.