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Blood

Chapter 17

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Cardiovascular systemBlood is a component ofFunction

♦Supply O2 to all cells & remove wastes

♦Transport hormones & other chemicals (e.g. ions)♦Immune response

Composed of♦The Heart♦Blood vessels♦BLOOD

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Characteristics of BloodBlood = fluid connective tissueComposed of a variety of cells and their extracellular

matrix

37-54%Formed elements

♦Red Blood Cells♦White Blood Cells♦Platelets

46-63%Liquid medium = Plasma

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PlasmaContains mostly water (92%)Electrolytes and proteins (7%)“Free-floating stuff”Proteins

♦Always remain in the plasma – give viscous consistency

3 main plasma proteins♦Albumin♦Globulins♦Fibrinogen

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PlasmaAlbumins

♦Help in maintaining osmotic pressure of blood♦Transport thyroid hormones, fatty acids, etc.

Globulins♦Immunoglobulins/antibodies for defense♦Transport ions & hormones

Fibrinogen♦Impt. in blood clotting

Blood tests: Plasma vs. SerumSerum = plasma without fibrinogen

♦Thus the clotting factors are removed♦but also removes Ca2+ ions

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Formed ElementsRed Blood Cells = Erythrocytes (RBCs)Function of RBC’s

♦Transports O2 from tissue to lungs♦Transports CO2 from cells/tissue to lungs

Structure♦Saucer-shaped cell = biconcave disk

Special features♦No nucleus♦No mitochondrion (no mitochondria)

Lack of these organelles is advantageous to function♦No nucleus = no cell division = less energy spent & more

space for O2

♦Cell can assume biconcave shape – this allows for the stacking of cells

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Formed Elements: RBC’s

Importance of Shape to function (review in text)

No mitochondria♦O2 necessary for ATP production♦If present, the O2 will be consumed♦Also gives more space in the cell

Fig. 17-2

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Fig. 17-3

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Molecular content of RBC’sStocked with Hemoglobin (Hb)

♦Protein ♦Makes up 95% of all intracellular proteins♦There are approx. 280 million molecules of Hb in each RBC♦Normal range in grams per mL whole blood = g/dl ?

Hb = protein with 4 pieces (subunits)4 polypeptide chains = Globins

♦α-globin & β-globin

Fig. 17-3

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Molecular content of RBC’sStocked with Hemoglobin (Hb)

4 polypeptide chains = Globins♦α-globin & β-globin

With each globin there is a heme group♦Special chemical compound containing Fe2+ ♦Fe2+ of globin binds to O2

Blood leaving lungs is rich in O2 ♦Fe- O2 = oxyhemoglobin – bright red in color

Blood going to lungs containing CO2 ♦= carbaminohemoglobin – dark red in color

Fig. 17-3

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Molecular content of RBC’s

RBC’s contain a special enzyme♦Carbonic Anhydrase

Helps in CO2 transport in the blood – (later)

Fig. 17-3

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Formed Elements: White Blood CellsWhite Blood Cells = Leukocytes

♦Approx. 0.1% of blood totalCome in many shapes and formsGranular (3 types)

♦Neutrophils♦Eosinophils♦Basophils

Agranular (2 types)♦Lymphocytes♦Monocytes

Common Features♦Prominent Nucleus♦Large size (compared to RBC’s)♦No Hemoglobin Fig. 17-1

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Formed Elements: White Blood CellsHandout = specific targets of each type of WBC’sFunctions:Clean Up & Defense

♦Detect pathogen invasions, provide protection♦Remove dead cells and debris

“Guarding the Body”♦“patrol the area” – travel along the edge of blood vessels

IF pathogen(s) have entered the body tissue & local defense has begun, chemicals are released

WBC’s are attracted to these chemicals & squeeze through endothelial cells to exit the blood vessel

They then find their way to the damaged tissue – this type of sensing and movement = chemotaxis

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Formed Elements: PlateletsPlatelets = Thrombocytes

Packages of cytoplasm

Function = clotting♦Repair of slightly damaged blood vessels

Fig. 17-2

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Blood – day 2

Chapter 17

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Formed Elements: ProductionRBCs, WBCs, & Platelets are synthesized in the body

Production & recycling

Production of blood cells = Hemopoiesis

All blood cells originate from Hemocytoblast cells

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Red Blood Cell ProductionLocation

♦Red bone marrow (myeloid tissue) of epiphysis of vertebrae, sternum, ribs, skull, scapulae, pelvis, proximal limb bones

Process – Fig. 17.5

Hemocytoblast → becomes RBC

Process = Erythropoeisis

Requires a hormone = erythropoetin (peptide)♦Stimulated by renal erythropoetic factor from the kidneys♦Recall/review Fig. 16-7b

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Red Blood Cell ProductionErythropoeisisErythropoetein (E.P.O.)Simple versionHemocytoblast loses nucleus

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ro

Fig. 17-2

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Fig. 17-2