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The Cardiovascular The Cardiovascular System: BloodSystem: Blood

The Cardiovascular The Cardiovascular System: BloodSystem: Blood

Chapter 14

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FunctionFunctionFunctionFunction

• Transportation-hormones, gasses, nutrients, ions, heat

• Regulation- pH, temperature, water balance in cells

• Protection- clotting, white cells interferons, complement

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CompositionCompositionCompositionComposition

• Connective tissue-Two parts• Plasma = soluble materials

(~55%)• Formed Elements = cells (~45%)• Percent occupied by red blood

cells (RBC) = hematocrit (Hct)• White blood cells (WBC) ~1%

Figure 14.1aFigure 14.1a

Figure 14.1bFigure 14.1b

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PlasmaPlasmaPlasmaPlasma

• ~91% water, 7% proteins, 1.5 % other solutes

• Proteins: Albumin (54%)- osmosis and carriers;

• Globulins (38%)- antibodies• Fibrinogen (7%)- clotting• Other: Electrolytes , nutrients,

gases, hormones, vitamins & waste products

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Formed ElementsFormed ElementsFormed ElementsFormed Elements

I. Red Blood CellsII. White blood cells

A. granular Leukocytes1. Neutrophils2. Eosinophils3. Basophils

B. Agranular leukocytes1. T & B lymphocytes & natural Killer cells2. monocytes

III Platelets

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Formation of Blood CellsFormation of Blood CellsFormation of Blood CellsFormation of Blood Cells

• Called hemopoiesis• Just before birth and throughout

life occurs in red bone marrow• Contains pluripotent stem cells• In response to specific

hormones these develop through a series of changes to form all of the blood cells

Figure 14.2aFigure 14.2a

Figure 14.2bFigure 14.2b

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Erythrocytes (RBCs)Erythrocytes (RBCs)Erythrocytes (RBCs)Erythrocytes (RBCs)

• Hemoglobin package- carries oxygenAlso carries some CO2

• Male has ~ 5.4 million cells/µl; Female has ~4.8 million

• membrane, no nucleus, flexible structure

• use glucose for ATP production to maintain ionic compositionNo mitochondria

• Wear out fast- live ~120 days

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RBC CyclingRBC CyclingRBC CyclingRBC Cycling

• cleared by macrophages (liver & Spleen)

• Fe- recycled in bone marrowCarried in blood on transferrin

• Heme bilirubin and excreted (bile)

• Globin A.A. recycled.

Figure 14.3Figure 14.3

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RBC SynthesisRBC SynthesisRBC SynthesisRBC Synthesis

• called erythropoiesis• From stem cells: hemocytoblasts• Released as reticulocytes

Mature to erythrocytes in 1-2 days

• Production & destruction is balanced

• Low O2 delivery (hypoxia)

• erythropoietin release (EPO) from kidney• Stimulates erythropoiesis

Figure 14.4Figure 14.4

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White Blood CellsWhite Blood CellsWhite Blood CellsWhite Blood Cells

• Defenses: phagocytes, antibody production and antibacterial action

• Phagocytes:Neutrophil- first respondersMonocytes macrophages (big eaters)Eosinophil- phagocitize antibody-antigen

complexes Involved in suppressing allergic responses

Basophil- intensify allergic reactions

• Immune response: T-cells, B-cells& natural killer (NK) cells

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WBC Life SpanWBC Life SpanWBC Life SpanWBC Life Span

• 5000-10,00 WBC /µl blood• Limited number of bacteria can be

eaten• Life span is a few days • During active infection may be hours• Leukocytosis= increased WBC

numbers response to stresses• Leukopenia = decreased WBC

numbers

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PlateletsPlateletsPlateletsPlatelets

• Myeloid stem cells megakaryocytes 2000 -3000 fragments = platelets

• Plug damaged blood vessels• Promote blood clotting• Life span 5-9 days

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HemostasisHemostasisHemostasisHemostasis

• Hemostasis = stationary blood• 1. Vascular reactions (spasm)

Response to damageQuick reduction of blood loss

• 2. platelet plug formationBecome sticky when contact damaged vessel

wall• 3. blood clotting (coagulation)

Series of chemical reactions involving clotting factors

• Clotting in unbroken vessel= thrombosis

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Coagulation Coagulation Coagulation Coagulation

• Extrinsic pathway common stepstissue factor(TF) from damaged cells 1

• Intrinsic Pathway common steps Materials “intrinsic” to blood 1

• 1. prothrombinase which causes• 2. prothrombin thrombin causes• 3. fibrinogen fibrin clot

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Clot Retraction & Vessel Clot Retraction & Vessel RepairRepair

Clot Retraction & Vessel Clot Retraction & Vessel RepairRepair

• Clot pugs ruptured area• Gradually contracts (retraction)• Pulls sides of wound together• Fibroblasts replace connective

tissue• epithelial cells repair lining

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Control MechanismsControl MechanismsControl MechanismsControl Mechanisms

•Fibrinolysis: dissolving of clot by activated plasmin enclosed in clot

• Clots can be triggered by roughness on vessel wall = thrombosis

• Loose clot = embolus and can block a small vessel = embolism

Figure 14.5Figure 14.5

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Blood TypesBlood TypesBlood TypesBlood Types

• Surface antigens- react with antibodies

• Divided into groups based on antigens> 24 blood groups and > 100

different antigens

• We will deal with ABO and Rh groups

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ABO GroupABO GroupABO GroupABO Group

• Two antigens = A & B• If have only A –type A• If have only B –type B• If neither then Type O• Blood usually has antibodies that can

react with antigense.g. anti-A antibody or anti-B antibody

• You don’t react with your own antigensThus: type A has anti-B and vice versa

Figure 14.6Figure 14.6

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Rh Blood GroupRh Blood GroupRh Blood GroupRh Blood Group

• Antigen discovered in rhesus monkey

• If have antigen- Rh+

• Normally don’t have antibodies• antibodies develop after the first

exposure from transfusion

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TransfusionsTransfusionsTransfusionsTransfusions

• If mismatched blood given antibodies bind to it and hemolyze cells

• Type AB has no AB antibodies so can receive any ABO type blood called Universal recipients

• Type O have neither antigen so can donate to any other ABO type called Universal donors

• Misleading because of many other blood groups that must be matched