Chapter 19: Blood Biology 141 A&P Brashear-Kaulfers

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Chapter 19 BloodBiology 141 APBrashear-Kaulfer
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What are the components of the cardiovascular
system, and their major functions?
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The Cardiovascular System

• A circulating transport system
• a pump (the heart)
• a conducting system (blood vessels)
• a fluid medium (blood)

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Functions of the Cardiovascular System

• To transport materials to and from cells
• oxygen and carbon dioxide
• nutrients
• hormones
• immune system components
• waste products

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What are the important components and major
functions of blood?BloodIs specialized fluid
of connective tissue -contains cells suspended in
a fluid matrix
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5 Functions of Blood

• Transport of dissolved substances
• Regulation of pH and ions
• Restriction of fluid losses at injury sites
• Defense against toxins and pathogens
• Stabilization of body temperature

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Whole Blood
Plasma Fluid-Water Dissolved plasma
proteins Other solutes Formed elements all
cells and solids
Figure 191a
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Plasma

• Is similar to, and exchanges fluids with,
  interstitial fluid
• Is matrix of formed elements

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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

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3 General Characteristics of Blood

• 38C (100.4F) is normal temperature
• High viscosity
• Slightly alkaline pH (7.357.45)
• Blood volume (liters) 7 of body weight
  (kilograms)
• adult male 5 to 6 liters
• adult female 4 to 5 liters

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Plasma
Makes up 5060 of blood volume More than 90 of
plasma is water
Figure 191b
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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 O2 and CO2
• Dissolved proteins
• plasma proteins do not pass through capillary
  walls

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3 Classes of Plasma Proteins

• Albumins (60)-Transport substances
• fatty acids
• thyroid hormones
• steroid hormones
• Globulins (35)- Antibodies, also called
  immunoglobulins
• Transport globulins (small molecules)
• hormone-binding proteins
• metalloproteins
• apolipoproteins (lipoproteins)
• steroid-binding proteins
• Fibrinogen (4)-Molecules form clots
• Produce long, insoluble strands of fibrin

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Other Plasma Proteins

• 1 of plasma
• changing quantities of specialized plasma
  proteins
• enzymes, hormones, and prohormones
• Origins of Plasma Proteins
• 90 made in liver
• Antibodies made by plasma cells
• Peptide hormones made by endocrine organs
• Serum -liquid part of a blood sample
• in which dissolved fibrinogen has converted to
  solid fibrin

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KEY CONCEPT

• Total blood volume (liters) 7 of body weight
  (kilograms)
• About 1/2 the volume of whole blood is cells and
  cell products
• Plasma resembles interstitial fluid, but contains
  a unique mixture of proteins not found in other
  extracellular fluids

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What are the characteristics and functions of
red blood cells?
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Red Blood Cells

• Red blood cells (RBCs) make up 99.9 of bloods
  formed elements
• Red blood cell count measurements
• reports the number of RBCs in 1 microliter whole
  blood
• RBC normal
• male 4.56.3 million
• female 4.5.5 million
• Hematocrit (packed cell volume, PCV)
• percentage of RBCs in centrifuged whole blood
• Hematocrit normal
• male 452
• female 347

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RBC Structure

• Small and highly specialized disc
• Thin in middle and thicker at edge

Lifespan of RBCs Lack nuclei, mitochondria, and
ribosomes Live about 120 days
Figure 192d
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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 µm RBC passes through 4 µm capillary

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Hemoglobin (Hb)

• Protein molecule, transports respiratory gases
• Normal hemoglobin (adult male)
• 1418 g/dl whole blood

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Hemoglobin Structure

• Complex quaternary structure

Figure 193
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Hemoglobin Structure

• 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)

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Fetal Hemoglobin

• Strong form of hemoglobin found in embryos
• Takes oxygen from mothers hemoglobin
• Carbaminohemoglobin
• With low oxygen (peripheral capillaries)
• hemoglobin releases oxygen
• binds carbon dioxide and carries it to lungs

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Anemia

• Hematocrit or hemoglobin levels are below normal
• Is caused by several conditions

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Recycling RBCs
Figure 194
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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)

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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

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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

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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

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RBC Maturation
Erythropoiesis - Red blood cell formation Occurs
only in red bone marrow (myeloid tissue) Stem
cells mature to become RBCs
Figure 195
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Hemocytoblasts

• Stem cells in bone marrow divide to produce
• myeloid stem cells
• become RBCs, some WBCs
• lymphoid stem cells
• become lymphocytes

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Stages of RBC Maturation

• Myeloid stem cell
• Proerythroblast
• Erythroblasts
• Reticulocyte
• Mature RBC
• Components for Building red blood cells
• amino acids
• iron
• vitamins B12, B6, and folic acid

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Stimulating Hormones

• Erythropoietin (EPO)
• Also called erythropoiesis-stimulating hormone
• secreted when oxygen in peripheral tissues is low
  (hypoxia)
• due to disease or high altitude

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RBC Tests
Table 191
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KEY CONCEPT- RBC

• Red blood cells (RBCs) are the most numerous
  cells in the body
• RBCs circulate for approximately 4 months before
  recycling
• Several million are produced each second
• Hemoglobin in RBCs transports
• oxygen from lungs to peripheral tissues
• carbon dioxide from tissues to lungs

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Blood Typing -Surface Antigens

• Are cell surface proteins that identify cells to
  immune system
• Normal cells are ignored and foreign cells
  attacked

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4 Basic Blood Types
Blood types are genetically determined By
presence or absence of RBC surface antigens A, B,
Rh
Figure 196a
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4 Basic Blood Types

• A (surface antigen A)
• B (surface antigen B)
• AB (antigens A and B)
• O (neither A nor B)
• Agglutinogens
• Antigens on surface of RBCs
• Screened by immune system
• Plasma antibodies attack (agglutinate) foreign
  antigens

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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

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The Rh Factor

• Also called D antigen
• Either Rh positive (Rh) or Rh negative (Rh)
• Only sensitized Rh blood has anti-Rh antibodies

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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

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Blood Type Test

• Determines blood type and compatibility

Cross-Match Test Performed on donor and recipient
blood for compatibility Without cross-match, type
O is universal donor
Figure 197
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Based on structures and functions, what are the
types of white blood cells, and what factors
regulate the production of each type?
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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

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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
• Have amoeboid movement
• Attracted to chemical stimuli (positive
  chemotaxis)
• Some are phagocytic
• neutrophils, eosinophils, and monocytes

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5 Types of WBCs
Neutrophils Eosinophils Basophils Monocytes Lympho
cytes
Figure 199
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Neutrophils

• Also called polymorphonuclear leukocytes
• 5070 of circulating WBCs
• Pale cytoplasm granules with
• lysosomal enzymes
• bactericides (hydrogen peroxide and superoxide)

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Neutrophil Action

• Very active, first to attack bacteria
• Engulf pathogens
• Digest pathogens
• Release prostaglandins and leukotrienes
• Form pus

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Degranulation

• Removing granules from cytoplasm
• Defensins
• peptides from lysosomes
• attack pathogen membranes

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Eosinophils

• Also called acidophils
• 24 of circulating WBCs
• Attack large parasites
• Excrete toxic compounds
• nitric oxide
• cytotoxic enzymes

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Eosinophil Actions

• Are sensitive to allergens
• Control inflammation with enzymes that counteract
  inflammatory effects of neutrophils and mast cells

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Basophils

• Are less than 1 of circulating WBCs
• Are small
• Accumulate in damaged tissue
• Basophil Actions
• Release histamine
• dilates blood vessels
• Release heparin
• prevents blood clotting

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Monocytes

• 28 of circulating WBCs
• Are large and spherical
• Enter peripheral tissues and become macrophages
• Macrophage Actions
• Engulf large particles and pathogens
• Secrete substances that attract immune system
  cells and fibroblasts to injured area

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Lymphocytes

• 2030 of circulating WBCs
• Are larger than RBCs
• Migrate in and out of blood
• Mostly in connective tissues and lymphatic organs
• Lymphocyte Actions
• Are part of the bodys specific defense system

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3 Classes of Lymphocytes

• T cells -Cell-mediated immunity
• Attack foreign cells directly
• 2. B cells -Humoral immunity
• Differentiate into plasma cells
• Synthesize antibodies
• 3. Natural killer (NK) cells -Detect and destroy
  abnormal tissue cells (cancers)

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The Differential Count of Circulating WBCs

• Detects changes in WBC populations
• Infections, inflammation, and allergic reactions
• WBC Disorders
• Leukopenia
• abnormally low WBC count
• Leukocytosis
• abnormally high WBC count
• Leukemia
• extremely high WBC count

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KEY CONCEPT

• RBCs outnumber WBCs 10001
• WBCs defend against infection, foreign cells, or
  toxins
• WBCs clean up and repair damaged tissues
• The most numerous WBCs
• neutrophils engulf bacteria
• Lymphocytes-are responsible for specific defenses
  of immune response

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WBC Production
Origins and Differentiation of Formed Elements
PLAY
Figure 1910
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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

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Lymphocytes

• Are produced by lymphoid stem cells
• Lymphopoiesis
• the production of lymphocytes

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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

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4 Colony-Stimulating Factors (CSFs)

• Hormones that regulate blood cell populations
• 1. M-CSF-stimulates monocyte production
• 2. G-CSF-stimulates granulocyte production
• neutrophils, eosinophils, and basophils

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Summary Formed Elements of Blood
Table 193
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Platelets

• Cell fragments involved in human clotting system
• Nonmammalian vertebrates have thrombocytes
  (nucleated cells)
• Circulates for 912 days
• Are removed by spleen
• 2/3 are reserved for emergencies

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Platelet Counts

• 150,000 to 500,000 per microliter
• Thrombocytopenia
• abnormally low platelet count
• Thrombocytosis
• abnormally high platelet count

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3 Functions of Platelets

• Release important clotting chemicals
• Temporarily patch damaged vessel walls
• Actively contract tissue after clot formation
• Platelet production- called thrombocytopoiesis
• occurs in bone marrow

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Megakaryocytes

• Giant cells
• Manufacture platelets from cytoplasm
• Hormonal Controls
• Thrombopoietin (TPO)
• Inteleukin-6 (IL-6)
• Multi-CSF

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What mechanisms control blood loss after injury,
and what is the reaction sequence in blood
clotting?
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Hemostasis

• The cessation of bleeding
• vascular phase
• platelet phase
• coagulation phase

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The Vascular Phase

• A cut triggers vascular spasm
• 30-minute contraction

Figure 1911a
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3 Steps of the Vascular Phase

• Endothelial cells contract
• expose basal lamina to bloodstream
• Endothelial cells release
• chemical factors
• ADP, tissue factor, and prostacyclin
• local hormones
• endothelins
• stimulate smooth muscle contraction and cell
  division
• Endothelial cell membranes become sticky
• seal off blood flow

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The Platelet Phase

• Begins within 15 seconds after injury

Figure 1911b
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The Platelet Phase

• Platelet adhesion (attachment)
• to sticky endothelial surfaces
• to basal laminae
• to exposed collagen fibers
• Platelet aggregation (stick together)
• forms platelet plug
• closes small breaks

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Activated Platelets Release Clotting Compounds

• Adenosine diphosphate (ADP)
• Thromboxane A2 and serotonin
• Clotting factors
• Platelet-derived growth factor (PDGF)
• Calcium ions

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Platelet Plug Size Restriction

• Prostacyclin
• released by endothelial cells
• inhibits platelet aggregation
• Inhibitory compounds
• released by other white blood cells
• Circulating enzymes
• break down ADP
• Negative (inhibitory) feedback
• from serotonin
• Development of blood clot
• isolates area

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The Coagulation Phase

• Begins 30 seconds or more after the injury

Figure 1912a
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The Coagulation Phase

• 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

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Clotting Factors

• Also called procoagulants
• Proteins or ions in plasma
• Required for normal clotting

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Plasma Clotting Factors
Table 194
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Cascade Reactions

• During coagulation phase
• Chain reactions of enzymes and proenzymes
• Form 3 pathways

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3 Coagulation Pathways

• Extrinsic pathway
• begins in the vessel wall
• outside blood stream
• Intrinsic pathway
• begins with circulating proenzymes
• within bloodstream

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3 Coagulation Pathways

• Common pathway
• where intrinsic and extrinsic pathways converge

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The Extrinsic Pathway

• Damaged cells release tissue factor (TF)
• TF other compounds enzyme complex
• Activates Factor X

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The Intrinsic Pathway

• Activation of enzymes by collagen
• Platelets release factors (e.g., PF3)
• Series of reactions activate Factor X

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The Common Pathway

• Enzymes activate Factor X
• Forms enzyme prothrombinase
• Converts prothrombin to thrombin
• Thrombin converts fibrinogen to fibrin

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Functions of Thrombin

• Stimulates formation of tissue factor
• stimulates release of PF-3
• forms positive feedback loop (intrinsic and
  extrinsic)
• accelerates clotting
• Bleeding Time
• Normally, a small puncture wound stops bleeding
  in 14 minutes

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Clotting Area Restriction

• Anticoagulants (plasma proteins)
• antithrombin-III
• alpha-2-macroglobulin
• Heparin
• Protein C (activated by thrombomodulin)
• Prostacyclin

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Other Factors

• Calcium ions (Ca2) and vitamin K are both
  essential to the clotting process

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Clot Retraction

• After clot has formed
• Platelets contract and pull torn area together
• Takes 3060 minutes

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Fibrinolysis

• Slow process of dissolving clot
• thrombin and tissue plasminogen activator (t-PA)
  
• activate plasminogen
• Plasminogen produces plasmin
• digests fibrin strands

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KEY CONCEPT-Platelets

• Platelets are involved in coordination of
  hemostasis (blood clotting)
• Platelets, activated by abnormal changes in local
  environment, release clotting factors and other
  chemicals
• Hemostasis is a complex cascade that builds a
  fibrous patch that can be remodeled and removed
  as the damaged area is repaired

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SUMMARY (1)

• Functions of cardiovascular system
• 5 functions of blood
• Structure of whole blood
• plasma and formed elements
• Process of blood cell formation (hemopoiesis)
• 3 classes of plasma proteins
• albumins
• globulins
• fibrinogen

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SUMMARY (2)

• RBC structure and function
• Hemoglobin structure and function
• RBC production and recycling
• Blood types
• ABO and Rh
• WBC structure and function
• 5 types of WBCs
• neutrophils
• eosinophils
• basophils
• monocytes
• lymphocytes

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SUMMARY (3)

• Differential WBC counts and disease
• WBC production
• Platelet structure and function
• Platelet production
• 3 phases of hemostasis
• vascular
• platelet
• coagulation
• Fibrinolysis