Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 11 The Cardiovascular System: Blood 12 - 1 11-1: Blood Characteristics • Blood—connective tissue containing cells suspended in fluid matrix • Functions – Transport gases, nutrients, hormones & waste – Regulate pH & ions – Restrict fluid loss at injury sites – Defend against toxins & pathogens – Stabilize body temp 12 - 2 Composition of Blood • Made of plasma & formed elements • pH: 7.35 – 7.45; volume: males 5 – 6 L, females 4 – 5 L Blood Collection & Analysis • Blood collected through venipuncture • Blood can be used to prepare blood smear to show different formed elements 12 - 3 11-1 Checkpoint 1. List five major functions of blood. 2. What two components make up whole blood? 3. Why is venipuncture a common technique for obtaining a blood sample? 12 - 4 11-2: Plasma Composition of Plasma • Blood is 55% plasma – Composed of plasma proteins, solutes & water Plasma Proteins • Types of plasma proteins – Albumins—majority of plasma; maintain pressure – Globulins—antibodies & transport proteins – Fibrinogens—blood clotting 11-2 Checkpoint 1. List the three major types of plasma proteins. 2. What would be the effects of a decrease in the amount of plasma proteins? 12 - 6 11-3: Red Blood Cells (RBCs) Abundance of RBCs • Blood is 45% RBCs (erythrocytes) • Hematocrit—percentage of whole blood volume occupied by formed elements – 99.9% RBCs, <0.1% WBCs, <0.1% platelets Structure of RBCs • RBC is biconcave disc, lacks a nucleus 12 - 8 Hemoglobin Structure & Function • Hemoglobin in RBC transports O2 & CO2 – 4 heme subunits bind with iron • Hemoglobin binding process – Lungs: hemoglobin binds to O2, releases CO2 – Tissues: hemoglobin binds to CO2, releases O2 • Anemia—RBCs have reduced hemoglobin content – Iron-deficiency anemia more common in women 12 - 9 RBC Life Span & Circulation • RBCs last about 120 days • Hemoglobin recycling – Hemolysis: RBC ruptures – Phagocytosis: Macrophages in body engulf RBCs, hemoglobin broken apart into heme & recycled by body • Heme converted to bilirubin (yellow pigment) – Excess bilirubin causes jaundice RBC Formation • Erythropoiesis—formation of RBCs – Occurs in red bone marrow • Erythropoiesis requires amino acids, iron & vitamins • Erythropoietin (EPO) released during low O2 levels (hypoxia) – Stimulates cell division in bone marrow – Speeds RBC maturation 11-3 Checkpoint 1. Describe hemoglobin. 2. What effect does dehydration have on an individual’s hematocrit? 3. What effect does a reduction in oxygen supply to the kidneys have on levels of EPO in the blood? 12 - 12 11-4: ABO Blood Types • Surface antigens trigger immune response • Presence/absence of antigens determines blood type – Type A—antigen A only – Type B—antigen B only – Type AB—antigens A & B – Type O—no antigens – Rh positive—Rh antigen present – Rh negative—Rh antigen absent 12 - 14 Cross-Reactions in Transfusions • Antibodies attack foreign antigens on RBCs • Type A blood – Antigen: Antigen A – Antibody: Anti-B – Can receive type A & O blood, not B or AB • Type B blood – Antigen: Antigen B – Antibody: Anti-A – Can receive type B & O blood, not A or AB • Type AB blood – Antigen: Antigens A & B – Antibody: no antibodies – Can receive all types of blood—universal recipient • Type O blood – Antigen: no antigens – Antibodies: Anti-A & Anti-B – Can be given to people with any blood type— universal donor – Can only receive type O blood 12 - 17 • Surface antigens + antibodies from incorrect blood = cross-reaction (transfusion reaction) • Agglutination—clumping of antigens & antibodies CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. Rh Blood Group Interactions • Rh- person receives Rh+ blood: • Immune system produces anti-Rh antibodies • No reaction until next transfusion • Rh- mother delivers Rh+ baby • Placenta causes blood to mix • Anti-Rh antibodies formed • Next Rh+ baby attacked by anti-Rh antibodies—erythroblastosis fetalis 12 - 19 12 - 20 11-4 Checkpoint 1. Which blood type(s) can be safely transfused into a person with Type AB blood? 2. Why can’t a person with Type A blood safely receive blood from a person with Type B blood? 12 - 21 11-5: White Blood Cells (WBCs) • WBCs (leukocytes) larger than RBCs, have a nucleus • Defend the body against pathogens; remove toxins, wastes, abnormal or damaged cells • Compose <0.1% of hematocrit 12 - 22 WBC Circulation & Movement • Characteristics of WBC movement: – Amoeboid movement—extend cytoplasm to move – Diapedesis—squeeze through capillary cells to exit bloodstream – Positive chemotaxis—attracted to chemical stimuli – Capable of phagocytosis—engulf pathogens or other materials 12 - 23 Types of WBCs • Neutrophils – Most numerous WBC – Attack & digest bacteria • Eosinophils – Attack objects coated with antibodies • Basophils – Release heparin (blood clotting) & histamine (inflammation 12 - 24 • Monocytes – Attack large objects, release chemicals to attract other WBCs • Lymphocytes – Continuously migrate through body – Attack foreign cells (crucial in immunity) Differential Count of WBCs • Differential count—indicates number of each type of cell – Determines presence of infections, disorders • Leukopenia—reduced number of WBCs • Leukocytosis—excessive numbers of WBCs – Extreme leukocytosis indicates leukemia 12 - 26 11-5 Checkpoint 1. Identify the five types of WBCs. 2. Which type of cell would you find in elevated numbers in a person producing large amounts of circulating antibodies to combat a virus? 12 - 27 11-6: Platelets • Platelets—cell fragments – Compose <0.1% of hematocrit • Megakaryocytes release platelets into bloodstream – Initiate clotting process • Thrombocytopenia (low platelet number) & thrombocytosis (high platelet number) 11-6 Checkpoint 1. Explain how platelets form. 2. List the primary functions of platelets. 12 - 29 11-7: Hemostasis • Hemostasis—process that halts bleeding & prevents loss of blood Phases of Hemostasis • Vascular phase – Cut blood vessel triggers vascular spasm (contraction) – Blood flow from small vessels slowed or stopped • Platelet phase – Platelets attach to inner blood vessel & mesh of collagen fibers – Forms a platelet plug to close break • Coagulation phase (blood clotting) – Protein mesh grows, traps blood cells & platelets – Uses clotting factors to aid in clotting process – Blood clot seals off damaged vessel 12 - 31 12 - 32 Clot Retraction & Removal • Clot retraction—platelets contract to pull edges of wound closer together • Fibrinolysis—dissolves clot – Plasminogen & tissue plasminogen activator (t-Pa) digest protein strands • t-Pa used in treatment of strokes 12 - 33 Abnormal Hemostasis • Thrombus—large blood clot attached to vessel wall • Embolus—drifting blood clot in the bloodstream – Can result in an embolism—blockage of blood vessel due to embolus • Hemophilia—inadequate production of clotting factors 12 - 34 11-7 Checkpoint 1. If a sample of red bone marrow has fewer than normal megakaryocytes, what body process would you expect to be impaired as a result? 2. What are the phases of hemostasis? 3. How is a thrombus different from an embolus? 12 - 35