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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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Blood – day 2

Chapter 17

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Formed Elements: PlateletsPlatelets = Thrombocytes

Packages of cytoplasm – no nucleus

Function = clotting♦Repair of slightly damaged blood vessels♦Stop blood loss from damaged blood vessel by forming a

“platelet plug”♦Contain numerous vessicles: release chemicals that

promote clotting

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 ProductionErythropoeisis

Erythropoetein (E.P.O.) = required hormone♦Stimulated by renal erythropoetic factor from kidneys♦Converts plasma protein to erythropoetin

Simple versionHemocytoblast becomes proerythroblastLoses nucleus – becomes reticulocyte

♦Hb is synthesizedReleased into bloodBecomes RBC after 1-2 days

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Red Blood Cell Production

Fig. 17-5

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Red Blood Cell ProductionErythropoeisis

…is triggered by low O2 levelsRequires proper supply of iron & vitamins (B12)The following:

♦low O2 / high altitudes♦Anemia♦Damaged lung surface

…trigger secretion of EPO

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The life of a RBCReleased into blood streamMatures after 1-2 daysTravels all over body repeatedlyAfter approx. 120 days RBC becomes damagedTherefore it is destroyed and recycledDamaged RBC is destroyed by MACROPHAGES in

the spleen, liver and bone marrowThe contents of the RBC are broken up and recycledSome of these contents are later used as building

blocks to make new RBCs

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The end of a RBC – recycle & reuse

Fig. 17-4

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The end of a RBC – issues/terms

Problems with the bile duct = ♦Increase in bilirubin in blood♦= yellow skin: Jaundice

If RBCs break in blood stream and not in macrophages

♦HemoglobinuriaKidney damage – you sometimes find intact RBCs in

urine ♦Hematuria

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White Blood Cell ProductionAlso made from hemacytoblastsRequire a different hormone (set of hormones)Colony – stimulating factors = C.S.F.CSFs are also involved in enhancing WBC function

How do we get 5 different leukocytes??

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Fig. 17-10

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White Blood Cell ProductionCSFs you need to know (most important ones):GM-CSF = distinguishes myeloblast from monoblastG-CSF = makes granular leukocytesM-CSF = triggers monocyte formation

For some blood cell production hormones…♦EPO, G-CSF, GM-CSF

…similar chemicals can by used as drug treatments to increase the levels of those cell types

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Fig. 17-10

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Platelet Production = ThromcytopoiesisHemocytoblast (in bone marrow)Megakaryocyte

♦Large cells♦Make proteins, enzymes, membrane

Shredded cytoplasm = plateletsHormones

♦Thrombopoietin (TPO)♦Interleucin-6 (IC-6)♦Multi-CSF

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Back to Red Blood CellsAnother important feature of RBCs Identification “tag”

♦Ensures that only siimilar/same type of RBCs remain in one blood stream

♦= a defense feature

ID tags = blood typeBlood type = different carbohydrates on the surface

called antigensAntigens are recognition factors

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Fig. 17-6

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Back to Red Blood CellsBlood plasma also carries antibodies

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Back to Red Blood CellsAntibodies match blood-typeAntibodies are there to detect if foreign blood cells are

presentIf B is given to A, anti-B reacts with B antigen

♦Agglutination – destroys cells♦In the bargain it also interferes with normal blood

ABO system of blood typingO

♦Universal donor but dilution factor is important b/c it has both antibodies

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Fig. 17-7

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Rh system+ or –Separate from ABO, but functions similarlySituation of concern = erythroblastosis fetalis

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Fig. 17-8

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Important Function of Platelets

Fig. 17-

WoundingStarts with breaking of skin – therefore blood vessels

are torn3 steps take place

Culminating in clot formationHappens in 2-6 minutes

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Well known blood disorders

Fig. 17-

Anemia

Leukemia

Mononucleosis

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Fig. 17-9

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Fig. 17-

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ro

Fig. 17-2

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Fig. 17-2