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


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


reserved.5

Hemopoiesis

• Process of blood cell production

• Two locations of hemopoiesis– Myeloid hemopoiesis in red

bone marrow– Lymphoid hemopoiesis in

lymphoid tissue


reserved.6

Hemopoiesis (cont’d.)

• Origin: Stem cell• Three paths

– Erythropoiesis– Leukopoiesis– Thrombopoiesis


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


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


reserved.9

Red Blood Cells: Oxygen Carriers

• Large, disc-shaped• Bendable• Contain

hemoglobin• Globin shapes RBC• Heme carries iron• Iron carries O2


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


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


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


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

Copyright © 2011, 2007 by Saunders,


14

Dismantling a Red Blood Cell


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


reserved.16

Anemia: Insufficient RBCs

• RBC production falters if conditions are disordered or necessary substances are missing.


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,


18

Classification of WBCsTypes Major Functions

GranulocytesNeutrophilsEosinophilsBasophils

AgranulocytesLymphocytesMonocytes

PhagocytosisResponse to parasitic infection; allergiesRelease of heparin

ImmunityPhagocytosis


reserved.19

Remembering Types of WBCs


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


reserved.21

Lesson 15-2 Objectives

• Identify the steps of hemostasis.• Describe the four blood types.• Describe the Rh factor.


reserved.22

Hemostasis: Stopping Bleeding

• Vascular spasm• Platelet plug• Coagulation


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


reserved.24

Fibrinolysis: Clot Breakdown


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)


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


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


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.


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.


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.


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.


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.


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.


reserved.34

Erythroblastosis Fetalis


reserved.35

Business

Chapter 015