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1/30/07
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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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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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