Chapter 19: The Blood

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Chapter 19 The Blood

• BIO 211 Lecture
• Instructor Dr. Gollwitzer

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• Today in class we will discuss
• The primary functions of the blood
• List the physical characteristics and major
  components of the blood
• Plasma
• Describe the composition and functions of plasma
• Describe the roles of various plasma proteins
• Red Blood Cells (RBCs)
• List the characteristics and functions of RBCs
• Describe the structure and function of hemoglobin
• Explain the basis for ABO and Rh blood types and
  the cause of incompatibilities

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2 Major Fluid (Circulatory) Systems

• Cardiovascular system (CVS)
• Circulating fluid blood (Chapter 19)
• Pump heart (Chapter 20)
• Conducting pipes blood vessels (Chapter 21)
• Lymphatic system (Chapter 22)
• Interconnected and interdependent with CVS
• CVS (bloodstream) ? fluid ? tissues ? fluid
  ? lymphatic vessels ? CVS
• CVS assists lymphatic system (defense system)
  blood carries lymphatic cells, antibodies,
  cytokines, etc.

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Blood

• Specialized fluid connective tissue
• Contains
• Cells in fluid matrix
• Proteins
• Functions
• Transport of dissolved substances
• Regulation of pH and ion composition
• Restriction of fluid loss at injury sites
• Defense against toxins and pathogens
• Stabilization of body temperature

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Functions Transportation

• Dissolved gases
• Oxygen (O2) from lungs to tissues
• Carbon dioxide (CO2) from tissues to lungs
• Nutrients
• Absorbed from digestive tract, adipose tissue,
  liver
• Hormones
• From endocrine glands to target cells
• Metabolic wastes
• Absorbs and carries from tissue cells to liver
• Immune system cells
• Defend tissues from infection and disease

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Functions Regulation of pH and Ion Composition
of Interstitial Fluids

• Occurs via diffusion between blood and
  interstitial fluids
• Eliminates local deficiencies or excesses of ions
• e.g., increases/decreases calcium or potassium
• Absorbs and neutralizes acids
• e.g., lactic acid produced by skeletal muscles

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Functions Restriction of Fluid Loss at Injury
Sites

• Via blood clotting
• Enzymes and other substances in blood respond to
  breaks in vessel walls by initiating clotting
  process
• Blood clot
• Temporary patch which prevents further blood loss

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Functions Defense Against Toxins and Pathogens

• Transports white blood cells (WBCs)
• Fight infections
• Remove debris from peripheral tissues
• Delivers antibodies
• Special attack proteins against invading
  organisms or foreign compounds

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Functions Stabilization of Body Temperature

• Absorbs heat generated by active skeletal muscles
  (heat reservoir)
• Redistributes heat to other tissues
• If body temp high
• Heat lost through skin
• If body temp low
• Warm blood directed to brain and other
  temp-sensitive organs

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Physical Characteristics of Blood

• Temperature 100.4 F
• High viscosity
• 5 times thicker than water
• Cells are stickier (more cohesive), more
  resistant to flow than water
• pH 7.4 (slightly basic/alkaline)
• Volume
• 4 (female) - 6(male) quarts
• 7 of BW in kg

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Composition of Whole Blood

• Whole blood plasma formed elements
• Plasma matrix (fluid part of blood)
• Plasma proteins in solution (vs. insoluble fibers
  like other CT)
• Makes blood more dense than water
• Formed elements suspended blood cells/cell
  fragments

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Composition of Whole Blood

• Formed elements (formed through hematopoiesis)
• RBCs (erythrocytes)
• Most abundant
• Transport O2 and CO2
• WBCs (leukocytes)
• Part of immune system/defense mechanisms
• Platelets
• Small, non-cellular, membrane-bound packets of
  cytoplasm
• Contain enzymes, substances important in clotting

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Plasma

• H20 (gt 90) plasma proteins other solutes
• Watery characteristic allows plasma to function
  as transportation medium for materials needed and
  no longer needed by bodys cells
• Slightly more than half the blood volume
• Plasma interstitial fluid (IF) most of the
  fluid outside cells (ECF, extracellular fluid)
• Primary differences b/w plasma and IF
• More dissolved protein in plasma (large size and
  globular shapes cant cross capillary walls)
• Higher levels of respiratory gases (O2, CO2) in
  IF due to activities of tissue cells

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Classes of Plasma Proteins

• Albumins (60)
• Globulins (35)
• Fibrinogen (4)
• Other (1)

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Albumins

• Most abundant
• Contribute to osmotic pressure
• Transport
• Fatty acids
• Thyroid hormones
• Steroid hormones

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Globulins

• Antibodies (immunoglobulins, IGs)
• Attack foreign proteins and pathogens
• Transport
• Small metal ions (Fe)
• Thyroid hormones
• Other compounds that otherwise might be lost at
  the kidneys or have low solubility in water

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Fibrinogen

• Produces fibrin (long, insoluble, protein
  strands)
• Forms blood clots
• In a blood sample, if remove clot (with clotting
  proteins), remainder serum
• To prevent clot use anticoagulant, e.g., EDTA,
  citrate
• KNOW if sample is plasma or serum (for blood
  tests)

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Other Plasma Proteins

• Enzymes
• Prohormones (proteins)
• Hormones

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Plasma Protein Synthesis

• gt90 by liver
• Liver disease can lead to excess bleeding
  (inadequate fibrinogen and other clotting
  proteins) and other blood disorder
• Plasma cells make antibodies
• Endocrine organs make peptide hormones

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Formed Elements

• RBCs, WBCs, platelets
• Formed in red bone marrow in adult
  (hematopoiesis)
• Differentiation
• Hemocytoblasts (stem cells) ?
• Lymphoid stem cells ? lymphocytes (WBCs)
• Myeloid stem cells ? RBCs, some WBCs, platelets
• Erythropoiesis
• RBC formation
• Stimulated by erythropoietin (EPO)
• Platelets formed from fragmentation of
  megakaryocytes

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RBCs

• Most abundant
• 99.9 of formed elements and 1/3 of ALL body
  cells
• Several million produced/sec
• Most specialized blood cell
• Contains hemoglobin that binds and transports O2
  and CO2 (primary function of both hemoglobin and
  RBCs)
• Normal RBC count
• Males 4-6 million/uL Females 4-5 million/uL
• Androgens stimulate RBC production, estrogens do
  not

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RBCs

• Biconcave disc (thin in middle, thick at edge
  like breath mint)
• Large surface area to volume
• Quickly absorbs and releases oxygen
• Can form stacks (like breath mints)
• Smooths flow through small blood vessels
• Can bend and flex
• To fit through small capillaries

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RBCs

• No nucleus, ribosomes, mitochondria
• Cannot divide
• Cannot synthesize enzymes or other proteins
• Cannot perform repairs (lifespan 120 days/3 mo)
• Low energy demand
• Gets energy from anaerobic metabolism of glucose
  absorbed from plasma
• Transported O2 is NOT stolen by RBC for energy
  needs

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Fig. 19-2, p. 644
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RBCs

• Hematocrit (packed cell volume, PCV)
• of formed elements in whole blood (most of
  which are RBCs)
• Male 46
• Female 42
• Increases with dehydration, EPO
• Decreases with internal bleeding, anemias,
  problems with RBC formation, e.g., sickle cell
  anemia

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Hemoglobin (Hb)

• Made of 4 globular protein subunits
• 2 alpha chains 2 beta chains
• Each subunit contains 1 heme molecule
• Organic ring structure around single Fe ion
• Makes up most of RBC
• Function
• Allows cells to reversibly bind and transport O2
  and CO2 on Fe
• When tissue O2 low O2 released from Hb, CO2
  binds
• When tissue O2 high O2 binds to Hb, CO2 released

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Fig. 19-3, p. 645
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Diseases Involving Hemoglobin

• Anemia
• Inadequate tissue O2 levels ? O2 starvation
• HCT too low
• Hb content of RBCs reduced
• Symptoms
• Weakness, lethargy, mental confusion

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Potentially Lethal Inherited Blood Disorders

• From mutations that alter DNA sequence for
  hemoglobin
• Thalassemia
• Cant produce enough alpha or beta chains of Hb
• RBC production slowed, mature RBCs fragile and
  short-lived
• Produces anemia
• Sickle cell anemia
• Change in amino acids of beta chain ? abnormal
  RBCs, lower O2 concentrations (because of
  abnormally shaped/defective Hb)
• Cells can become stuck in capillaries ?
  circulatory block, cell death

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Blood Types

• Determined by antigens on surface of RBCs
• Antigen anything that can trigger an immune
  response defense mechanism
• gt50 surface antigens on RBC, but A, B, and Rh are
  most important
• 4 basic blood types
• Blood type A surface antigen A
• Blood type B surface antigen B
• Blood type AB surface antigens A and B
  (universal recipient)
• Blood type O neither A or B surface antigens
  (universal donor)

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Blood Types

• Plasma always contains antibodies that will react
  with foreign surface antigens, but not with
  normal
• Type A blood surface antigen A on RBCs and
  anti-B antibodies in plasma

Fig. 19-7, p. 651
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Blood Types

• Rh positive surface antigen Rh
• Rh negative no Rh surface antigen
• Plasma anti-Rh antibodies present in Rh- ONLY if
  sensitized by previous exposure to Rh RBCs
• Rh- mom has from first Rh baby

Fig. 19-9, p. 654-655
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Cross-reaction (Transfusion Reaction)

• Same surface antigen and Ab ? agglutination
  (clumping) and hemolysis (cell death)
• Plugs small vessels in vital organs kidneys,
  lungs, heart, brain fatal
• Blood for transfusions must be carefully analyzed
• Determine blood type expose recipients blood to
  antibodies A and B
• Cross-match expose recipients blood to donor
  blood reveals all cross-reactions

Fig. 19-7b, p. 651
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• Today in class we will discuss
• White Blood Cells (WBCs)
• Categories of WBCs based on their structure and
  function
• The significance of changes in a differential
  count
• Structure and Function of platelets
• The definition of hemostasis
• The mechanisms that control blood loss
• The definition of hemopoiesis
• The role of hemocytoblasts, lymphoid stem cells,
  myeloid stem cells, megakaryocytes, and
  reticulocytes
• Locations of body sites used for blood collection
  and the basic physical characteristics of blood
  samples drawn from those sites

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WBCs

• WBCs vs. RBCs
• Have nuclei and other organelles
• Lack hemoglobin
• 100s 1000s of WBCs/uL vs. millions of RBCs/uL
• Small fraction of WBCs circulate in blood
• Lifespan hrs (3 mo. for RBCs)
• General functions
• Defend body against invasion by pathogens and
  foreign proteins (lymphocytes)
• Remove toxins, wastes
• Attack abnormal or damaged cells (all other WBCs)

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WBCs

• Types of WBCs distinguished by staining
  techniques
• Granulocytes abundant (usually stained)
  granules (secretory vesicles and lysosomes)
• Neutrophils - granules difficult to stain
• Eosinophils - stain red-pink with acidic, red dye
  eosin
• Basophils - stain deep purple-blue with basic
  dyes
• Agranulocytes - have smaller stained granules
  nuclei darkly stained
• Monocytes
• Lymphocytes

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WBCs Circulation

• Small fraction of WBCs circulate in blood
• Circulate for only small portion of life span
  (hrs)
• Most in CT or lymphatic organs
• Migrate through loose and dense connective tissue
• Use blood stream
• To travel from one organ to another
• For rapid transportation to areas of injury or
  invasion
• When traveling through capillaries, can detect
  chemical signs of damage to surrounding tissues
• Leave bloodstream to enter damaged area

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WBCs Movement

• 4 characteristics of circulating WBCs
• Amoeboid movements (like the blob) allows
  movement along walls of blood vessels and through
  tissues
• Can move out of blood vessels (diapedesis)
• Attracted to specific chemical stimuli (positive
  chemotaxis)
• Guides WBCs to invading pathogens, damaged
  tissues, and active WBCs
• Neutrophils, eosinophils, and monocytes capable
  of phagocytosis
• Engulf pathogens, cell debris, and other
  materials
• Neutrophils and eosinophils microphages
• Monocytes macrophages

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Hierarchy of WBCs

• Lymphocytes (T cells, B cells, NKCs)
• Phagocytes
• Microphages
• Eosinophils
• Neutrophils
• Macrophages
• Monocytes
• Basophils ? mast cells

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WBCs

• Neutrophils 50-70
• Lymphocytes 20-30
• Monocytes 2-8
• Eosinophils 2-4
• Basophils - lt 1
• Mnemonic
• Never Let Monkeys Eat Bananas
• Neutrophils Lymphocytes Monocytes
  Eosinophils Basophils

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Neutrophils

• Most abundant WBC in healthy individual (50-70
  of circulating WBCs)
• Nucleus has 2-5 lobes polymorphonuclear
  leukocytes (PMNs)
• Cytoplasm has pale granules
• Contain lysosomal enzymes and bactericidal
  compounds
• Highly mobile FIRST WBC to arrive at injury
  site
• Release hormones
• Prostaglandins (coordinate local cellular
  activities)
• Leukotrienes (coordinate tissue responses to
  injury or disease)
• Phagocytic cells (microphages) specialize in
  attacking/digesting bacteria
• 10-hr life span, only 30 min if actively engulfing

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Figure 19-10a White Blood Cells
RBC
Neutrophil
LM ? 1500
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Lymphocytes

• 20-30 of circulating WBCs
• Smallest WBCs
• Large nucleus with thin halo of cytoplasm
• Most in CT and organs of lymphatic system
• Part of the bodys specific defense system
• e.g., T cells, B cells, natural killer cells
  (NKCs)
• NKCs important in preventing cancer
• Detect and destruct abnormal tissue cells

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Figure 19-10e White Blood Cells
RBC
Lymphocyte
LM ? 1500
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Monocytes

• 2-8 of WBCs
• Large cells with large nucleus
• Become macrophages
• Very phagocytic
• Engulf large particles and pathogens
• Secrete substances that attract immune system
  cells and fibroblasts to injured area

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Figure 19-10d White Blood Cells
RBC
LM ? 1500
Monocyte
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Eosinophils

• 2-4 of WBCs
• Red/acid-staining granules
• Two-lobed nucleus
• Phagocytic cells (microphages)
• Engulf bacteria, protozoa, cellular debris
• Exocytose toxic compounds
• Defend against large multicellular parasites
  (flukes, parasitic worms)
• Also involved in allergic reactions

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Figure 19-10b White Blood Cells
RBC
LM ? 1500
Eosinophil
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Basophils

• lt1 of circulating WBCs
• Numerous granules dark/stained with basic
  (blue-purple) dyes
• Migrate to injury sites, release
• Histamine
• Dilates blood vessels
• Heparin
• Prevents blood clotting and promotes inflammation

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Figure 19-10c White Blood Cells
RBC
LM ? 1500
Basophil
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Table 19-3 Formed Elements of the Blood
Table 19-3, p 658
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Table 19-3 Formed Elements of the Blood
Table 19-3, p 658
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WBC Count (Differential)

• Done with blood smear, manually counted in field
  of 100 WBC
• Changes in circulating counts of WBCs caused by
• Pathogenic infections
• Inflammation
• Allergic reactions
• Abnormal conditions
• Leukopenia low, inadequate numbers of WBCs
• Leukocytosis high, excessive numbers of WBCs
• Modest increase infection, inflammation,
  allergic reactions
• Extreme case leukemia

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Platelets

• Cell fragments involved in clotting system
• Flattened discs appear round when viewed from
  above and spindle-shaped in section or blood
  smear
• 350,000/uL of circulating blood (accounts for 2/3
  of platelets)
• Other 1/3 in spleen and other vascular organs
• Produced in bone marrow
• Continuously replaced
• Life cycle 9-12 days, then phagocytosed in
  spleen

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Platelet Function in Hemostasis

• Transport chemicals/ enzymes important to
  clotting process
• Form temporary patch in walls of damaged vessel
• Cause contraction after clot formation

Figure 19-12 The Vascular, Platelet, and
Coagulation Phases of Hemostasis and Clot
Retraction (Step 3)
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Hemostasis

• process of stopping blood loss from the
  vessels, or the cessation of bleeding

Figure 19-12 The Vascular, Platelet, and
Coagulation Phases of Hemostasis and Clot
Retraction
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Hemostasis

• 3 Phases of Hemostasis
• Vascular Phase
• Vascular spasm smooth muscle contraction to
  decrease the vessel diameter
• Blood flow stops or slows as a result
• Platelet Phase
• Platelet adhesion occurs platelets adhere to
  any exposed surface
• Platelet plug forms continues to add to it
• Coagulation Phase
• Fibrinogen produces fibrin the fibers add to
  platelets along with other chemicals
• Covers the platelet plug forming a clot

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Platelets

• Abnormal conditions
• Thrombocytopenia
• Low platelet count
• Due to decreased production or increased
  destruction
• Symptoms include bleeding in GI tract, skin,
  inside CNS
• Thrombocytosis
• High platelet count
• Accelerated formation of infection, inflammation,
  cancer

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Figure 19-11 The Origins and Differentiation of
Formed Elements
Hemocytoblasts
Red bone marrow
Lymphoid Stem Cells
Myeloid Stem Cells
Progenitor Cells
Blast Cells
Myeloblast
Proerythroblast
Lymphoblast
Monoblast
Myelocytes
Erythroblast stages
Band Cells
Ejection of nucleus
Megakaryocyte
Promonocyte
Prolymphocyte
Reticulocyte
Erythrocyte
Platelets
Monocyte
Lymphocyte
Basophil
Eosinophil
Neutrophil
Red Blood Cells (RBCs)
Agranulocytes
Granulocytes
White Blood Cells (WBCs)
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Hemopoiesis

• blood cell formation and differentiation
• Hemocytoblasts Stem cells in myeloid tissue
  that divide to produce
• Myeloid stem cells become RBCs, some WBCs
• Lymphoid stem cells become lymphocytes
• Megakaryocytes
• Giant cells in bone marrow
• Manufacture platelets from cytoplasm
• Reticulocyte immature red blood cell that has
  shed its nucleus
• is released into circulation where it will
  complete its maturation process to form a mature
  RBC.
• last stage of development before RBC completes
  erythropoiesis ( RBC formation)

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Collection Methods

• Venipuncture
• From median cubital vein
• Superficial veins easy to locate
• Walls of veins thinner than arteries
• Venous BP lower, so wound seals quickly
• Peripheral capillaries
• From finger, ear lobe, toe, heel puncture
  (stick)
• Drop of blood to prepare blood smear
• Arterial puncture
• From radial artery (wrist) or brachial artery
  (elbow)
• Check efficiency of gas exchange at lungs