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Transcript of Chapter 015
The Human Body in Health and Illness, 4th edition
Barbara Herlihy
Chapter 15:Blood
Lesson 15-1 Objectives
• Describe the three functions of blood.• Describe the composition of blood.• Describe the three types of blood cells:
erythrocytes, leukocytes, and thrombocytes.• Explain the formation of blood cells.• Explain the breakdown of red blood cells and
the formation of bilirubin.
Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights
reserved.2
Three General Functions of Blood
• Transportation– Oxygen, nutrients, waste
• Regulation– Temperature, acid-base, fluid-electrolyte balance
• Protection– Against infection and bleeding
Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights
reserved.3
Hematocrit• Plasma
– 55% of total– Clear yellowish liquid
• Formed elements – 45% of total – Erythrocytes (RBCs)– Leukocytes (WBCs)– Thrombocytes
(platelets)Copyright © 2011, 2007 by Saunders,
an imprint of Elsevier Inc. All rights reserved.
4
Other Characteristics of Blood
• Whole blood– Viscosity (three to five times thicker than H2O)
– pH (7.35 to 7.45)
• Plasma– Water, electrolytes, ions, and waste– Plasma proteins: Albumin, clotting factors, gamma
globulins– Serum: Plasma minus clotting factors
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reserved.5
Hemopoiesis
• Process of blood cell production
• Two locations of hemopoiesis– Myeloid hemopoiesis in red
bone marrow– Lymphoid hemopoiesis in
lymphoid tissue
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reserved.6
Hemopoiesis (cont’d.)
• Origin: Stem cell• Three paths
– Erythropoiesis– Leukopoiesis– Thrombopoiesis
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reserved.7
Bone Marrow Depression
• Occurs if bone marrow cannot produce enough blood cells.– Also called myelosuppression
• Results– Aplastic anemia: RBC deficiency– Leukopenia: WBC deficiency– Thrombocytopenia: Platelet deficiency– Pancytopenia: Depression of all blood cells
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reserved.8
Overactive Bone Marrow
• Overactive bone marrow leads to excess RBC production.– Called polycythemia (vera or secondary)
• Polycythemia vera– Burdens the heart– Overwhelms clotting system– Causes beet-red face and palms
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reserved.9
Red Blood Cells: Oxygen Carriers
• Large, disc-shaped• Bendable• Contain
hemoglobin• Globin shapes RBC• Heme carries iron• Iron carries O2
Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights
reserved.10
Why Blood Changes Its Color
• Oxyhemoglobin– O2 binds loosely with iron (Fe)
– Makes blood bright red– Lack of O2 makes blood bluish red
• Carbaminohemoglobin– CO2 binds with globin
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reserved.11
Conditions for Healthy RBCs
• Correct genetic code for hemoglobin• Healthy bone marrow• Iron• Vitamin B12 and intrinsic factor
• Folic acid• Healthy kidneys and erythropoietin• Absence of bleeding and hemolysis
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reserved.12
Shape of Red Blood Cells
• Large disc, thick rim• RBC bends, fits
through tiny vessels to deliver O2
• Sickle cell anemia: RBC does not bend, blocks vessel, fails to deliver O2
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reserved.13
Regulating RBC Production• Low O2 level in blood
• Kidney secretes erythropoietin (EPO)
• EPO stimulates bone marrow to produce RBCs
• RBCs increase, thus increasing O2
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an imprint of Elsevier Inc. All rights reserved.
14
Dismantling a Red Blood Cell
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reserved.15
Jaundice
Hemolytic JaundiceRapid breakdown of RBCs
Hyperbilirubinemia
Yellow stained tissue
Obstructive JaundiceNormal rate of RBC
breakdown but diminished excretion of
bilirubin in bile
Yellow, stained tissue
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reserved.16
Anemia: Insufficient RBCs
• RBC production falters if conditions are disordered or necessary substances are missing.
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reserved.17
White Blood Cells (WBCs)• Protect the body against
infection and inflammation • Phagocytes
– Neutrophils – Monocytes
• Can leave the blood vessels– To site of infection or
inflammationCopyright © 2011, 2007 by Saunders,
an imprint of Elsevier Inc. All rights reserved.
18
Classification of WBCsTypes Major Functions
GranulocytesNeutrophilsEosinophilsBasophils
AgranulocytesLymphocytesMonocytes
PhagocytosisResponse to parasitic infection; allergiesRelease of heparin
ImmunityPhagocytosis
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reserved.19
Remembering Types of WBCs
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reserved.20
Platelets or Thrombocytes
• Tiny structures– Fragments of megakaryocytes– Produced in red bone marrow
• Life span of 5 to 9 days• Function to prevent blood loss
– Key role in hemostasis
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reserved.21
Lesson 15-2 Objectives
• Identify the steps of hemostasis.• Describe the four blood types.• Describe the Rh factor.
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reserved.22
Hemostasis: Stopping Bleeding
• Vascular spasm• Platelet plug• Coagulation
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reserved.23
Formation of a Blood Clot1. Injury produces
PTA. 2. PTA activates
prothrombin to form thrombin.
3. Thrombin activates fibrinogen to form fibrin fibers (clot).
4. Clot retraction
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reserved.24
Fibrinolysis: Clot Breakdown
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reserved.25
Drugs that Affect Clotting
• Antiplatelet drugs– Aspirin, NSAIDs, clopidogrel
• Anticoagulants– Heparin (antithrombin)– Coumadin (prevents formation of prothrombin)
• Fibrinolytic or “clot buster” drugs– Tissue plasminogen activator (TPA)
Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights
reserved.26
Four Types of Blood• Type A
A antigen on RBC Anti-B antibodies in plasma
• Type B B antigen on RBC Anti-A antibodies in plasma
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reserved.27
Four Types of Blood (cont’d.)
• Type AB Both A and B antigens on RBC Neither anti-A nor anti-B antibodies in plasma
• Type O Neither A nor B antigen on RBC Both anti-A and anti-B antibodies in plasma
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reserved.28
Agglutination: Clumping of RBCs
• Blood clumps in response to interactions between antigens and antibodies.
• Example of a mismatched transfusion– Type A recipient has A antigens on RBC and anti-B
antibodies in plasma Type B donor has B antigen on RBC Result: Anti-B antibodies of recipient attack Bantigen of donor’s blood, causing agglutination and hemolysis.
Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights
reserved.29
Type O: “Universal” Blood Donor
• Type O blood has no antigens on RBCs.• Anti-A and anti-B antibodies of all other blood
types have no antigen to attack.• So, type O blood can be safely donated to all
recipients.
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reserved.30
Type AB: “Universal” Recipient
• Type AB has neither anti-A nor anti-B antibodies in the plasma.
• Type AB has no antibodies to attack antigens in any blood type—A, B, AB, or O.
• So, type AB can safely receive blood of any type.
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reserved.31
Rh Factor: An Additional Antigen • People with Rh factor are Rh
positive (+). Types A(+), B(+), AB(+), and O(+)
• Those without Rh factor are Rh() Types A(), B(), AB(), and O()
• Rh() persons initially have no anti-Rh antibodies in their blood, but develop them after exposure to the Rh factor.
Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights
reserved.32
Rh Factor: Two Considerations
• Blood transfusions Rh() blood can be donated to Rh(+) recipients Rh(+) blood cannot be donated to Rh() recipients
o The true universal donor is O().o The true universal recipient is AB(+).
• Rh incompatibility during pregnancy causes erythroblastosis fetalis.
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reserved.33
Rh Incompatibility in Pregnancy
• Condition: Mother is Rh() and baby is Rh(+).• In late pregnancy, Rh(+) blood moves from
baby to mother.• Mother develops anti-Rh antibodies.• Mother’s anti-Rh antibodies move into baby,
causing agglutination and hemolysis.
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reserved.34
Erythroblastosis Fetalis
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reserved.35