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FUNCTIONS OF BLOOD Transportation- O2 and CO2, nutrients, waste, hormones Regulation- pH (buffers), heat, osmotic pressure Protection- clotting, immune system Connective tissue: has no fibers The only fluid tissue in the body Composed of formed elements suspended in a nonliving fluid called plasma BLOOD CHARACTERISTICS Can be separated into layers with centrifuge Heavier, thicker, more viscous than H2O (5x) Temperature of 100.4 F pH of 7.4 8% body weight 5-6 liters (1.5 gallons) in males 4-5 liters (1.2 gallons) in females Plasma: Liquid matrix (ECF) (55% of total blood volume) Over 90% water Over 100 substances dissolved - Figure 10.1 Proteins (most abundant) Nutrients Lipids Electrolytes Respiratory gases Wastes Homeostatic mechanisms keep fairly constant Erythrocytes RBCs (45% blood volume) carry O2 No nucleus or organelles No mitosis/ metabolism Outnumber white blood cells 1,000 to 1 5 million RBC/mm3 Hemoglobin (4 protein complex)- 33% volume Responsible for color of blood 1 RBC contains~250 million hemoglobin molecules Erythrocytes RBCs (45% blood volume) Antigens on membrane determine ABO blood type and Rh factor Worn down RBCs destroyed in spleen and liver (macrophages)- 120 day life span Too few RBCs or hemoglobin= anemia Not enough O2 intake= hypoxia Leukocytes (WBCs): 1% of blood volume Have nucleus Defend against bacteria, viruses, parasites, tumor cells Separated into granulocytes (3 types) and agranulocytes (2 types) (Table 10.2) GRANULOCYTES Neutrophils (40-70%of WBCs)- phagocytic (small granules) Eosinophils (1-4%)- kill parasites/ controls inflammation/ release histaminases (fight allergic reaction) Basophils (<1%)- release heparin, histamine, serotonin AGRANULOCYTES Monocytes (4-8%)- phagocytic (large) Lymphocytes (20-45%)- provide immunity B and T cells produce antibodies Thrombocytes (platelets) Fragments of megakaryocytes Repair slightly damaged vessels Promote clotting link Occurs in red bone marrow 100 billion cells produced daily All arise from hemocytoblast (stem cell) NORMAL BONE MARROW nucleated erythroid precursors eosinophil normal megakaryocyte FORMATION OF RED BLOOD CELLS Process takes 3-5 days Rate of production controlled by erythropoietin (hormone) FORMATION OF WHITE BLOOD CELLS AND PLATELETS Stimulated by hormones Released bacteria) by chemical signals (inflammation, HEMOSTASIS: STOPPAGE OF BLEEDING Three phases a) b) c) Vascular spasms Platelet plug formation Coagulation Vascular spasms—smooth muscle contracts Vasoconstriction decreases blood loss Platelet plug formation– exposed collagen fibers cause platelets to adhere to damaged area Platelets cause nearby platelets to become sticky and form plug Coagulation—at the same time Formation of mesh of fibrin strands trap RBCs to make clot Process normally takes 3-6 minutes HUMAN BLOOD GROUPS Due to proteins (antigens) on plasma membranes of RBCs Antigens of one type are recognized as foreign by antibodies of another Antibodies bind to foreign RBCs and cause agglutination (clumping) and rupture (hemolysis) ABO and Rh blood groups are most important BLOOD TRANSFUSION Blood Group O A B AB • Prevalence Blood Rec. **** *** ** * Only O O or A O or B All If the wrong blood type is used the person’s own immune system immediately attacks the donor’s blood and causes clots and RBC destruction that can lead to total kidney failure and death. NO AGGLUTINATION REACTION • A person with blood type A can receive blood from a donor with blood type A. – The anti-B antibodies in the recipient do not combine with the type A antigens on the red blood cells of the donor. AGGLUTINATION REACTION A person with blood type B cannot receive blood from a donor with blood type A. The anti-A antibodies in the recipient will combine with the type B antigens on the red blood cells of the donor. Rh BLOOD TYPE Rh+: have Rh antigen and no antibodies Rh-: have no antigens and no antibodies Rh-negative people will develop antibodies to the Rh antigen if they are exposed to the Rh-positive blood If a Rh-negative woman becomes pregnant with a Rhpositive fetus she may make antibodies to the fetus’ RBCs This can be prevented with RhoGAM HEMOLYTIC DISEASE OF THE NEWBORN (HDN) HDN is the most common problem with Rh incompatibility. AGGLUTINATION REACTIONS