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The Cardiovascular System. The Blood. Fluids of the Body . blood composed of plasma and a variety of cells transports nutrients and wastes. interstitial fluid bathes the cells of the body. Cells of the body are serviced by 2 fluids:.
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The Cardiovascular System The Blood
Fluids of the Body • blood • composed of plasma and a variety of cells • transports nutrients and wastes • interstitial fluid • bathes the cells of the body • Cells of the body are serviced by 2 fluids: • Nutrients and oxygen diffuse from the blood into the interstitial fluid & then into the cells • Wastes move in the reverse direction
Functions of Blood • Transportation • O2, CO2, metabolic wastes, nutrients, heat & hormones • Regulation • pH through buffers • body temperature • coolant properties of water • vasodilatation of surface vessels dump heat • water content of cells by interactions with dissolved ions and proteins • Protection from disease & loss of blood
Physical Characteristics of Blood • Denser and more viscous than water • Temperature of 38oC (100.4oF) • pH range 7.35-7.45 • 8 % of total body weight (20% of extracellular fluid) • Blood volume • 5 to 6 liters in average male • 4 to 5 liters in average female • hormonal negative feedback systems maintain constant blood volume and osmotic pressure
Plasma Water (~91%) Proteins (~7%) albumins globulins fibrinogen Other Solutes (~1.5%) electrolytes nutrients gases regulatory substances waste products
Hematocrit • Percentage of total blood volume occupied by red blood cells • female normal range: 38 - 46% (average of 42%) • male normal range: 40 - 54% (average of 47%) • Anemia • not enough RBCs or not enough hemoglobin • Polycythemia • too many RBCs (over 65%) • Dehydration, blood doping in athletes
Red Blood Cells O2 / CO2 transport Provides RBCs their ability to carry oxygen No nucleus Biconcave shape
Control of Erythropoiesis
White Blood Cells Characteristics Nucleus lobed round Granules granular agranular
Lymphocyte Functions: Immune response Direct attack Antibodies Characteristics: Agranular Round nucleus Pale blue cytoplasm
Monocyte Functions: Phagocytosis Become macrophages Characteristics: Large Agranular U-shaped nucleus
Neutrophil Functions: Phagocytize bacteria Characteristics: Nucleus multi-lobed Inconspicuous granules
Eosinophil Functions: Kills parasitic worms Destroys antigen-antibody complexes Characteristics: Nucleus bilobed Red granules
Basophil Functions: Release histamine Contain heparin Characteristics: Nucleus lobed Blue-purple granules
Emigration of WBCs • WBCs roll along endothelium, stick to it & squeeze between cells. • adhesion molecules (selectins) help WBCs stick to endothelium • displayed near site of injury • molecules (integrins) found on neutrophils assist in movement through wall • Neutrophils & macrophages phagocytize bacteria & debris • chemotaxis of both • kinins from injury site & toxins
WBC Physiology • Less numerous than RBCs • 5000 to 10,000 cells per drop of blood • 1 WBC for every 700 RBC • Leukocytosis is a high white blood cell count • microbes, strenuous exercise, anesthesia or surgery • Leukopenia is low white blood cell count • radiation, shock or chemotherapy • Only 2% of total WBC population is in circulating blood at any given time • rest is in lymphatic fluid, skin, lungs, lymph nodes & spleen
Differential WBC Count • Detection of changes in numbers of circulating WBCs (percentages of each type) • indicates infection, poisoning, leukemia, chemotherapy, parasites or allergy reaction • Normal WBC counts • neutrophils 60-70% (up if bacterial infection) • lymphocyte 20-25% (up if viral infection) • monocytes 3 -- 8 % (up if fungal/viral infection) • eosinophil 2 -- 4 % (up if parasite or allergy reaction) • basophil <1% (up if allergy reaction or hypothyroid)
Complete Blood Count • Screens for anemia and infection • Total RBC, WBC & platelet counts; differential WBC; hematocrit and hemoglobin measurements • Normal hemoglobin range • infants have 14 to 20 g/100mL of blood • adult females have 12 to 16 g/100mL of blood • adult males have 13.5 to 18g/100mL of blood
Platelets • Myeloid stem cells develop eventually into a megakaryocyte • Splinters into 2000-3000 fragments • Each fragment enclosed in a piece of plasma membrane • Disc-shaped with many vesicles but no nucleus • Help stop blood loss by forming platelet plug • Granules contain blood clot promoting chemicals • Short life span – 5-9 days
Hemostasis - sequence of responses to stop bleeding 1. Vascular spasm 2. Platelet plug formation 3. Coagulation (clotting)
Clotting Cascade
Rh Factor Rh+ has Rh antigen no Rh antibody Rh- no Rh antigen no Rh antibody exposure of Rh- to Rh+ will produce antibody
Anemia - reduced oxygen carrying capacity of the blood. 1. Insufficient number of RBCs a. hemorrhagic anemia b. hemolytic anemia c. aplastic anemia 2. Decreased hemoglobin content a. iron-deficiency anemia b. pernicious anemia 3. Abnormal hemoglobin a. thalassemia b. sickle-cell anemia
Sickle-Cell Disease (SCD) • Genetic defect in hemoglobin molecule (Hb-S) that changes 2 amino acids • at very low O2 levels, RBC is deformed by changes in hemoglobin molecule within the RBC • sickle-shaped cells rupture easily = causing anemia & clots • Person with only one sickle cell gene • increased resistance to malaria because RBC membranes leak K+ & lowered levels of K+ kill the parasite infecting the red blood cells
Hemophilia • Inherited deficiency of clotting factors • bleeding spontaneously or after minor trauma • subcutaneous & intramuscular hemorrhaging • nosebleeds, blood in urine, articular bleeding & pain • Hemophilia A lacks factor VIII (males only) • most common • Hemophilia B lacks factor IX (males only) • Hemophilia C (males & females) • less severe because alternate clotting activator exists • Treatment is transfusions of fresh plasma or concentrates of the missing clotting factor
Leukemia • Acute leukemia • uncontrolled production of immature leukocytes • crowding out of normal red bone marrow cells by production of immature WBC • prevents production of RBC & platelets • Chronic leukemia • accumulation of mature WBC in bloodstream because they do not die • classified by type of WBC that is predominant---monocytic, lymphocytic