 Consists of blood cells & plasma  Blood cells = Erythrocytes (RBC’s), Leukocytes (WBC’s), & Thrombocytes (Platelets)  Blood is 55% plasma & 45% blood cells  Woman has ≈ 5 liters  Man has ≈ 6 liters

 Transport  Nutrients, waste, hormones, enzymes, O 2 & CO 2  Regulation of body temp due to high volume of H 2 O in plasma  Helps regulate body pH  Helps regulate water content of cells/Osmosis  Clotting: prevents fluid loss  Protection against pathogens (immune response, production of antibodies, destruction of bacteria/viruses, removal of cellular debris & allergic reactions)

 91% water  7% proteins: 1. Albumin: maintains osmotic pressure & water balance 2. Globulins: antibodies, complements (immune response) & transport molecules 3. Fibrinogens: important role in clotting  2% solutes:  Ions, nutrients, waste products, gases, enzymes & hormones

 95% of blood cell volume; biconcave disks  No nucleus, simple structures, don’t divide & live ≈ 120 days  Composed of a network of protein called stroma, cytoplasm, lipids (cholesterol) & hemoglobin (red pigment ≈ 33% of cell’s volume)

 Function:  Transport O 2 & CO 2 →→ Hemoglobin allows this  Hemoglobin:  Globin = protein  Heme = pigment containing 4 iron atoms  Iron combines with O 2 in the lungs & releases it in tissues; Bright red in color  Globin at tissues combines with CO 2 & releases it at lungs; Dark red in color

 2 subcategories: Granular & Nongranular  Have nuclei & no pigment; larger than RBC’s  General function in immune response:  Combat inflammation & infection  Can leave the blood stream & move into tissues via ameboid movement  Phagocytosis: “cell eating”

1. Neutrophils: 60% - 70% of WBC’s  Most active in WBC’s response to tissue destruction by bacteria  Stay in blood for 12 hours & then move to tissues where they phagocytize (eat) foreign substances  Secrete enzyme Lysozyme that destroys certain bacteria  Pus contains dead neutrophils, cell debris & fluids

2. Eosinophils: 2% - 4% of WBC’s  Combat irritants (pollen, dust, pet dander, etc) that causes allergies  Produce antihistamines 3. Basophils: 0.5% - 1% of WBC’s  Involved in allergic reactions  Releases heparin (anticoagulant), histamine (inflammatory substance) & serotonin (a vasoconstrictor)

1. Monocytes: 3% - 8% of WBC’s  Phagocytotic: eat bacteria, dead cells &/or cellular debris  Largest; after they leave blood & enter tissue, they increase in size & are called Macrophages 2. Lymphocytes: 20% - 25% of WBC’s  Production of antibodies & play important role in immune response  Smallest; several types: B & T lymphocytes  Control cancer cells, destroy microorganisms & reject foreign tissues

 Disk-shaped cellular fragments with a nucleus  Prevent fluid loss when blood vessels are damaged

 When larger blood vessels are damaged, clotting mechanism takes over  Cut vessel is rough & irregular shaped  3 stages to clotting/coagulation 1. Rough surface of vessel causes platelets to clump together at the site of the injury Tissue releases thromboplastin which produces prothrombin activator Requires Ca 2+, certain proteins & phospholipids

2. Ca 2+ & prothrombin activator converts prothrombin into thrombin 3. Soluble fibrinogen is converted into insoluble fibrin  Thrombin catalyzes the reaction  Fibrin forms long threads that act like a net = CLOT Clot forms & traps blood cells & platelets in the fibrin threads & bleeding stops

 Syneresis: clot retraction; tightening of clot so wound gets smaller & smaller  Serum (blood plasma minus clotting factors) surrounds wound under clot & hemorrhage is stopped  Blood vessel repairs itself  Fibronolysis occurs: blood clot dissolves

 Build up of cholesterol mass (Plaque) on smooth walls of UNDAMAGED blood vessels can cause clot formation  Called Thrombosis & clot is called a Thrombus  Thrombus may dissolve or a piece can dislodge & get transported in blood = Embolus  Embolus can get stuck in a vessel & cut-off circulation = Embolism  If tissues are killed = Infarction

 Agglutination: clumping of RBC’s, A.K.A transfusion reaction  Caused by reaction between antibodies in plasma & surface antigens on RBC’s  Caused by mismatched blood types  Headache, difficulty breathing, face flushed, pain in neck, chest & lower back, jaundice & kidney failure

 Presence or absence of antigens on RBC surface: antigen A & antigen B  Inherited; 4 possible antigen combinations:  A only: Type A  B only: Type B  A & B : Type AB  Neither A nor B: Type O  Antibodies are formed during infancy against the ABO antigens NOT present on our own RBC’s  Type A: antibody anti-B  Type B: antibody anti-A  Type AB: neither antibody →  Type O: both anti-A & anti-B Universal Recipient Universal Donor

 Inherited; named after Rhesus monkey where antigen 1 st discovered  If antigen D is found on RBC, the blood is Rh positive  If the RBC lacks the antigen, blood is Rh negative  Anti-Rh antibodies only develop after initial exposure to Rh-positive blood  Rh-negative person receives transfusion from Rh-positive person = no reaction (1 st time) but anti-Rh antibodies form  If 2 nd exposure happens, agglutination occurs