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Ch19 Blood Sum 09

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    Ch19 Blood Sum 09 Ch19 Blood Sum 09 Presentation Transcript

    • Ch. 19 Blood The Cardiovascular System
      • A circulating transport system:
        • a pump (the heart)
        • a conducting system (blood vessels)
        • a fluid medium (blood)
      Functions of the Cardiovascular System
      • To transport materials to and from cells:
        • oxygen and carbon dioxide
        • nutrients
        • hormones
        • immune system components
        • waste products
    • Blood
      • Is specialized fluid of connective tissue
      • Contains cells suspended in a fluid matrix
      5 Functions of Blood
      • Transport of dissolved substances
        • Gases-O2 from lungs to tissues
        • Nutrients-from digestive tract, storage, or liver
        • Hormones-such as from endocrine glands to target cells
        • Waste products-from cells to kidneys
      • Regulation of pH and ions
      • Regulation of pH and ions
            • Ions – either add or subtract i.e. Ca or K by diffusion w/ interstitial fluid & blood
            • Absorbs & neutralize acid
          • - i.e lactic acid from skeletal muscles
      • Restriction of fluid losses at injury sites
        • - Clotting
      • Defense against toxins and pathogens
        • - WBC – transported by blood to fight infection & remove debris
      • Stabilization of body temperature
        • - Heat loss via skin if hot
        • - Heat retention to brain and other vital organs via shunting
    • Whole Blood
      • Plasma :
        • Fluid proteins in solution
        • Like interstitial fluid
      • Formed elements :
        • all cells and cell fragments
      Plasma
      • Water
      • Dissolved plasma proteins
      • Other solutes
      • similar to, & exchanges fluids with, interstitial fluid
      • Is matrix of formed elements
    • 3 Types of Formed Elements
      • Red blood cells ( RBCs ) or erythrocytes :
        • transport oxygen
      • White blood cells ( WBCs ) or leukocytes :
        • part of the immune system
      • Platelets : cell fragments involved in clotting
      Hemopoiesis
      • Process of producing formed elements
      • By myeloid and lymphoid stem cells
      Fractionation
      • Process of separating whole blood for clinical analysis:
        • into plasma and formed elements
    • 3 General Characteristics of Blood
      • 38°C (100.4°F) is normal temperature
      • High viscosity
      • Slightly alkaline pH (7.35–7.45)
      Blood Volume
      • Blood volume (liters) = 7% of body weight (kilograms):
        • adult male: 5 to 6 liters
        • adult female: 4 to 5 liters
    • Plasma
      • Makes up 50–60% of blood volume
      • More than 90% of plasma is water
      Figure 19–1b
    • Extracellular Fluids
      • Interstitial fluid (IF) and plasma
      • Materials plasma and IF exchange across capillary walls:
        • water
        • ions
        • small solutes
      Differences between Plasma and IF
      • Levels of O 2 and CO 2
      • Dissolved proteins:
        • plasma proteins do not pass through capillary walls
    • 3 Classes of Plasma Proteins
      • Albumins (60%)
      • Globulins (35%)
      • Fibrinogen (4%)
      Albumins
      • Transport substances:
        • fatty acids
        • thyroid hormones
        • steroid hormones
      Fibrinogen
      • Molecules form clots
      • Produce long, insoluble strands of fibrin
      • If remove clotting proteins, = serum
    • Globulins
      • Antibodies , also called immunoglobulins
        • - Attack foreign bodies
      • Transport globulins (small molecules):
        • hormone-binding proteins – thyroid binding protein binds thyroid hormones; transcortin binds acth (adrenocorticoytropic hormone), stimulates thyroid
        • Metalloproteins- i.e. transferrin for Fe
        • apolipoproteins ( lipoproteins )
        • steroid-binding proteins – i.e. testosterone binding hormone binds & transports testosterone
    • Serum
      • Liquid part of a blood sample in which dissolved fibrinogen has converted to solid fibrin
      Other Plasma Proteins
      • 1% of plasma:
        • changing quantities of specialized plasma proteins
        • enzymes, hormones, and prohormones
          • TSH, FSH, LH, insulin, prolactin
      Origins of Plasma Proteins
      • 90% made in liver
        • All albumin and fibrinogen
      • Antibodies made by plasma cells made by lymphocytes
      • Peptide hormones made by endocrine organs
    • Red Blood Cells
      • Red blood cells (RBCs) make up 99.9% of blood’s formed elements
      Measuring RBCs
      • Red blood cell count:
        • reports # of RBCs in 1 microliter whole blood
      • Hematocrit (packed cell volume, PCV):
        • percentage of RBCs in centrifuged whole blood
      Normal Blood Counts
      • RBC : male: 4.5–6.3 million, female: 4.–5.5 million
      • Hematocrit :
        • male: 40–54%, female: 37–47%
        • Why different? Males have androgens
        • that stimulate RBC production
    • RBC Structure
      • Small and highly specialized disc
      • Thin in middle and thicker at edge
      Figure 19–2d Importance of RBC - Shape and Size
      • High surface-to-volume ratio:
        • quickly absorbs and releases oxygen
      • Discs form stacks:
        • smoothes flow through narrow blood vessels
      • Discs bend and flex entering small capillaries:
        • 7.8 µ m RBC passes through 4 µ m capillary
    • Lifespan of RBCs
      • Lack nuclei, mitochondria, and ribosomes
      • Live about 120 days
      Hemoglobin (Hb)
      • Protein molecule, transports respiratory gases
      • Responsible for cells ability to transport O2 and CO2
      • Normal hemoglobin:
        • 14–18 g/dl whole blood - males
        • 12-16 g/dl “” - females
    • Hemoglobin Structure
      • Complex quaternary structure
      Figure 19–3
      • 4 globular protein subunits:
        • each with 1 molecule of heme
        • each heme contains 1 iron ion
      • Iron ions easily:
        • associate with oxygen ( oxyhemoglobin )
        • or dissociate from oxygen ( deoxyhemoglobin )
    • Fetal Hemoglobin
      • Strong form of hemoglobin found in embryo/fetus
      • Takes oxygen from mother’s hemoglobin at the placenta begins last 7 months in utero and continues over the first year
      • FH can be stimulated in adults with SCA or thalassemia – only adult from of hemaglobin is abnormal
      Hemoglobin Function
      • Each RBC has 280 million Hb molecules
      • Each Hb molecule has 4 heme units
      • So each RBC potentially has more 1 billion O 2 molecules
    • Carbaminohemoglobin
      • With low oxygen (peripheral capillaries):
        • hemoglobin releases oxygen which makes plasma CO2 elevated
        • Alpha and beta chains binds carbon dioxide and carries it to lungs
        • Carbaminohemoglobin is formed
        • RBC then absorb O2 and releases CO2
      Anemia
      • Hematocrit or hemoglobin levels are below normal
      • Is caused by several conditions
    • Recycling RBCs
      • 1% of circulating RBCs wear out per day:
        • about 3 million RBCs per second
      • Macrophages of liver, spleen, and bone marrow:
        • monitor RBCs
        • engulf RBCs before membranes rupture (hemolyze)
      Figure 19–4
    • Diagnosing Disorders
      • Hemoglobinuria :
        • hemoglobin breakdown products in urine due to excess hemolysis in blood stream
      • Hematuria :
        • whole red blood cells in urine due to kidney or tissue damage
      Hemoglobin Recycling
      • Phagocytes break hemoglobin into components:
        • globular proteins to amino acids
        • heme to biliverdin
        • iron
    • Iron Recycling
      • To transport proteins ( transferrin )
      • To storage proteins ( feritin and hemosiderin )
      Breakdown of Biliverdin
      • Biliverdin (green) is converted to bilirubin (yellow)
      • Bilirubin is:
        • excreted by liver (bile)
        • jaundice is caused by bilirubin buildup
        • converted by intestinal bacteria to urobilins and stercobilins
    • RBC Maturation
      • Red blood cell formation
      • Occurs only in red bone marrow (myeloid tissue)
      • Stem cells mature to become RBCs
      Figure 19–5 Erythropoiesis Hemocytoblasts
      • Stem cells in bone marrow divide to produce:
        • myeloid stem cells :
          • become RBCs, some WBCs
        • lymphoid stem cells :
          • become lymphocytes
    • Stages of RBC Maturation
      • Myeloid stem cell
      • Proerythroblast
      • Erythroblasts
      • Reticulocyte
      • Mature RBC
      Components
      • Building red blood cells requires:
        • amino acids
        • iron
        • vitamins B 12 , B 6 , and folic acid
    • Pernicious Anemia
      • Low RBC production
      • Due to unavailability of vitamin B 12
      Stimulating Hormones
      • Erythropoietin (EPO)
      • Also called erythropoiesis-stimulating hormone:
        • secreted when oxygen in peripheral tissues is low ( hypoxia )
        • due to disease or high altitude
    • RBC Tests Table 19–1
    • Surface Antigens
      • Are cell surface proteins that identify cells to immune system
        • Triggers immune response
      • Normal cells are ignored and foreign cells attacked
        • Each cell has surface AG (antigens)
        • Allows for recognition of self
      Blood Types
      • Are genetically determined
      • By presence or absence of RBC surface antigens A , B , Rh
    • 4 Basic Blood Types
      • A (surface antigen A)
      • B (surface antigen B)
      • AB (antigens A and B)
      • O (neither A nor B)
      Figure 19–6a
    • Agglutinogens
      • Antigens on surface of RBCs
      • Screened by immune system
      • Plasma antibodies attack ( agglutinate ) foreign antigens
      Blood Plasma Antibodies
      • Type A: type B antibodies
      • Type B: type A antibodies
      • Type O: both A and B antibodies
      • Type AB: neither A nor B
    • The Rh Factor
      • Also called D antigen
      • Either Rh positive (Rh + ) or Rh negative (Rh — )
      • Only sensitized Rh — blood has anti-Rh antibodies
      • So . . .
        • Rh+ mom has Rh- baby - no problems ever
        • Rh- mom + Rh+ dad = Rh+ baby – no problem for pregnancy
        • Blood will mix around delivery & mom will make anti-Rh AB
        • Second baby that is Rh+ will be attacked by mom’s anti-Rh AB can cause death at or before delivery
      • Known as Hemolytic Disease of the Newborn or erythroblastalis fetalis
      • Newborn born with this is anemic and jaundiced
      • May have to have complete transfusion
      • RhoGam – to mom prevents production of anti-Rh AB last 3 months of pregnancy and before and after delivery
    • Cross-Reaction
      • Also called transfusion reaction
      • Plasma antibody meets its specific surface antigen
      • Blood will agglutinate and hemolyze
      • If donor and recipient blood types not compatible
      Figure 19–6b
    • White Blood Cells ( WBCs )
      • Also called leukocytes
      • Do not have hemoglobin
      • Have nuclei and other organelles
      WBC Functions
      • Defend against pathogens
      • Remove toxins and wastes
      • Attack abnormal cells
      WBC Movement
      • Most WBCs in connective tissue proper & lymphatic system organs
      • Small numbers in blood: 6000 to 9000 per microliter
    • Circulating WBCs
      • Migrate out of bloodstream
        • - Margination-activated WBCs adhere to vessel walls, then can squeeze thru (emigration or diapedesis)
      • Have amoeboid movement
        • - Gliding movement, needs ATP and Ca
        • - Movement of emigration
      • Attracted to chemical stimuli ( positive chemotaxis )
        • - Chemicals guide WBC to invading pathogens, damaged tissues, and other WBC
      • Some are phagocytic:
        • neutrophils, eosinophils (microphages), and monocytes (macrophage)
        • Engulf waste and pathogens
    • Types of WBCs
      • Neutrophils
      • Eosinophils
      • Basophils
      • Monocytes
      • Lymphocytes
      Figure 19–9
    • Neutrophils
      • Also called polymorphonuclear leukocytes
      • 50–70% of circulating WBCs
      • 12 um in dia
      • 10 hour life span - eats 12-24 bacteria first
      • Very dense 2-5 segment nucleus
      • Pale cytoplasm granules with lysosomal enzymes & bactericides (hydrogen peroxide and superoxide)
      Neutrophil Action
      • Very active, first to attack bacteria, fungi, and some viruses
      • Engulf pathogens
      • Digest pathogens
      • Release prostaglandins (hormones) and leukotrienes (calls other cells). Contributes to local inflammation
      • Form pus (dead neutrophils, cell debris and waste)
    • Eosinophils
      • Also called acidophils
      • 2–4% of circulating WBCs
      • 12 um dia
      • 2 lobed nucleus
      • Attack large parasites, then toxic compounds: nitric oxide & cytotoxic enzymes
      Eosinophil Actions
      • Are sensitive to allergens
      • Control inflammation with enzymes that counteract inflammatory effects of neutrophils and mast cells
    • Basophils
      • Are less than 1% of circulating WBCs
      • Are small - <8-10 um diameter
      • Migrate to site via capallaries
      • Accumulate in damaged tissue
      Basophil Actions
      • Release chemicals that attract basophils and eosinophils
      • Granuales discharged into interstitial fluid. They contain:
      • histamine :
        • dilates blood vessels
      • heparin :
        • prevents blood clotting
        • Both enhance inflammation
    • Monocytes
      • += 15 um diam
      • 2–8% of circulating WBCs
      • Are large and spherical
      • Large or kidney nucleus
      • Enter peripheral tissues and become macrophages after 24 hours – aggressive
      Macrophage Actions
      • Engulf large particles and pathogens
      • Secrete substances that attract immune system cells and fibroblasts to injured area
    • Lymphocytes
      • 20–30% of circulating WBCs
      • Very small, but larger than RBCs
      • Large round nucleus w/ thin cytopalmic halo
      • Migrate in and out of blood
      • Mostly in connective tissues & lymphatic organs
      Lymphocyte Actions
      • Are part of the body’s specific defense system
      • 3 classes
      • T cells
      • B cells
      • Natural killer (NK) cells
    • T cells
      • Cell-mediated immunity
      • Attack foreign cells directly
      • Coordinates immune response
      B cells
      • Humoral immunity
        • Produce and distribute AB
      • Differentiate into plasma cells
        • Synthesize and distribute antibodies
      Natural Killer Cells (NK)
      • Immune survelliance
      • Detect and destroy abnormal tissue cells (cancers)
    • WBC Disorders
      • Leukopenia : abnormally low WBC count
      • Leukocytosis : abnormally high WBC count
      • Leukemia : extremely high WBC count
      WBC Production
      • All blood cells originate from hemocytoblasts:
        • which produce myeloid stem cells and lymphoid stem cells
    • Myeloid Stem Cells
      • Differentiate into progenitor cells :
        • which produce all WBCs except lymphocytes
      Lymphocytes
      • Are produced by lymphoid stem cells
      • Lymphopoiesis : the production of lymphocytes
      WBC Development
      • WBCs, except monocytes: develop fully in bone marrow
      • Monocytes: develop into macrophages in peripheral tissues
    • Other Lymphopoiesis
      • Some lymphoid stem cells migrate to peripheral lymphoid tissues (thymus, spleen, lymph nodes)
      • Also produce lymphocytes
    • Summary: Formed Elements of Blood Table 19–3
    • Platelets
      • Cell fragments involved in human clotting system - 4um dia and 1 um thick – “sticky”
      • Nonmammalian vertebrates have t hrombocytes (nucleated cells)
      Platelet Circulation
      • Circulates for 9–12 days
      • Dead removed by phagocytosis in spleen
      • 2/3 are reserved for emergencies
      Platelet Counts
      • 150,000 to 500,000 per microliter
      • Thrombocytopenia : abnormally low platelet count
      • Thrombocytosis : abnormally high platelet count
    • 3 Functions of Platelets
      • Release important clotting chemicals
      • Temporarily patch damaged vessel walls
      • Actively contract tissue after clot formation
      Platelet Production
      • Also called thrombocytopoiesis : occurs in bone marrow
      Megakaryocytes
      • Giant cells
      • Manufacture platelets from cytoplasm
      • Each cell produces ~4000 platelets
    • Hemostasis
      • The cessation of bleeding:
        • vascular phase
        • platelet phase
        • coagulation phase
      • Endothelial cells contract
      • Contraction is due to
      • 1. Endothelial cells and
      • platelets releasing chemicals
      • 2. pain receptors initiate reflexes
        • stimulate smooth muscle contraction
      • Endothelial cell membranes become “sticky”:
      • - seal off blood flow
      • Von Willebrand factor (large plasma protein) synthesized by endothelial cells causes the stickiness by binding to proteins and cells
      The Vascular Phase
      • A cut triggers immediate response = vascular spasm
      • 20 to 30-minute contraction
    • The Platelet Phase
      • Begins within 15 seconds after injury
      Figure 19–11b
      • Platelet adhesion (attachment):
        • to sticky endothelial surfaces
        • to basal laminae
        • to exposed collagen fibers
      • Platelet aggregation (stick together):
        • forms platelet plug which closes small breaks
    • Activated Platelets Release Clotting Compounds
      • Granules in Platelets break down and release
        • Adenosine diphosphate (ADP) – aggregating agent (more platelets)
        • Thromboxane A 2 and serotonin – enhance vascular spasm
    • This is a positive feedback cycle that activates and attracts more and more platelets to the area. Within 1 minute a platelet plug is built Platelet Plug: Size Restriction
      • Prostacyclin :
        • released by endothelial cells
        • inhibits platelet aggregation
      • Inhibitory compounds:
        • released by other white blood cells
    • The Coagulation Phase
      • Begins 30 seconds or more after the injury
      Figure 19–12a
      • Blood clotting ( coagulation ):
        • Involves a series of steps
        • converts circulating fibrinogen into insoluble fibrin
      • Blood Clot
        • Fibrin network
        • Covers platelet plug
        • Traps blood cells
        • Seals off area
      • Clotting factors
        • Also called procoagulants
        • Proteins or ions in plasma
        • Required for normal clotting
    • Cascade Reactions
      • During coagulation phase
      • Chain reactions of enzymes and proenzymes
      • Form 3 pathways
      3 Coagulation Pathways
      • Extrinsic pathway :
        • begins in the vessel wall
        • outside blood stream
      • Intrinsic pathway :
        • begins with circulating proenzymes
        • within bloodstream
      • Common pathway:
        • where intrinsic and extrinsic pathways converge
    • 3 Coagulation Pathways The Extrinsic Pathway
      • Damaged cells release tissue factor (TF)
      • TF + other compounds = enzyme complex
      • Activates Factor X
      The Intrinsic Pathway
      • Activation of enzymes by collagen
      • Platelets release factors ( e.g., PF–3 )
      • Series of reactions activate Factor X
    • The Common Pathway
      • Enzymes activate Factor X
      • Forms enzyme prothrombinase
      • Converts prothrombin to thrombin
      • Thrombin converts fibrinogen to fibrin
        • Thrombin stimulates formation of tissue factor
          • stimulates release of PF-3:
          • forms positive feedback loop (intrinsic and extrinsic):
            • accelerates clotting
      Clotting: Area Restriction
      • Anticoagulants (plasma proteins): antithrombin-III & alpha-2-macroglobulin
      • Heparin
      • Protein C (activated by thrombomodulin )
      • Prostacyclin
    • Other Factors
      • Calcium ions (Ca 2+ ) and vitamin K are both essential to the clotting process
      Clot Retraction
      • After clot has formed:
        • Platelets contract and pull torn area together
      • Takes 30–60 minutes
      Fibrinolysis
      • Slow process of dissolving clot:
        • thrombin and tissue plasminogen activator (t-PA) : activate plasminogen
      • Plasminogen produces plasmin : digests fibrin strands
    • Disorders of Hemostasis
      • Thrombembolic disorders – clots too easily
        • Thrombus – clot that develops and persists in an unbroken blood vessel (may prevent blood flow and cause tissue death) - Coronary thrombosis
        • Embolus – thrombus that breaks away from the vessel wall and travels through bloodstream
        • Embolism – obstructs a vessel (pulmonary embolism)
        • Bedridden patients, long flights (slow moving blood)
      • Bleeding Disorders – prevent normal clotting
        • Thrombocytopenia – platelet numbers low
        • Impaired liver function – not able to synthesize coagulants
        • Hemophilias – several hereditary conditions (person doesn’t make the clotting factors correctly