Blood

Ch. 17

Introduction

Human blood

Blood and blood cells

BloodRed blood cells, white blood cells, platelets,

plasmaBlood volume and composition

Hematocrit45% cells, 55% plasma

Plasma composition-water, amino acids, proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, cellular wastes

Blood volume – females – 4-5 liters, males – 5-6 liters

Red blood cells Erythrocytes-bi-concave

discs 1/3 hemoglobin by

volume Description

Oxyhemoglobin – oxygen + hemoglobin

Deoxyhemoglobin – dark red

Non nucleated – nuclei discarded during development – can’t reproduce or make protein

Hemoglobin composed of: Globins – 4 proteins Heme – one molecule of

iron Oxygen combines with

heme

Red blood cell counts

Males - 5,500,000 mm3Female - 4,800,000 mm3Measures Oxygen-carrying

capacity (changes based on health and is used to diagnose)

Anemia – less than 10g per 100 ml

Red blood cell production and control

(erythropoiesis) Embryo and fetus Adult red blood

cell production Red blood cell life

span – 120 days Negative feedback

mechanism Erythropoietin –

from kidneys Dietary factors

Destruction of red blood cells

Macrophages phagocytize

Hemoglobin - heme and globin

Heme decomposed - iron, biliverdin and bilirubin

White blood cellsLeukocytes – white blood cellsHelp defend body against diseaseFormed from Hemocytoblasts as

needed (in response to hormones5 types - distinguished by: size,

granular appearance, nucleus shape and staining

White blood cell chasing bacteria

Types of white blood cells Neutrophils – stain red, fine

granules, multilobed nucleus, make up 54-62%

Eosinophils – stain deep red, bilobed nucleus, coarse granules, make up 1-3%

Basophils – stain blue, few granules, less than 1%

Monocytes – large, stain blue, variable nucleus shape, 3-9%

Lymphocytes – large nucleus, 25-33%, long lived

Monocytes and neutrophils – most active phagocytic cells

Functions of white blood cells Diapedesis – squeezing

between cells lining walls of blood vessels in order to attack bacteria and debris. Neutrophils and monocytes –

phagocytic. (monocytes engulf larger particles)

Eosinophils-moderate allergic reactions and defend against parasites

Basophils-migrate to damaged tissues/release histamine to promote inflammation and heparin to inhibit blood clotting.

Lymphocytes-specific immune reactions and antibody production.

White blood cell counts

Cubic milliliter - 5,000 to 9,000Differential white blood cell count

pinpoints nature of an illness. Indicates bacteria or viral illness. Lists percentages and types of white blood cells.

Leukocytosis - after infection. Excess leukocytes

Leucopenia – abnormal low white blood cells count - Aids

Blood platelets

Fragments of megakaryocytesRepair damaged blood vessels by

sticking to broken edgesNormal Counts - 150,000 to

350,000 per mm3

Blood plasma

Description – clear, straw coloredMostly water

Transport nutrients and gasesRegulate fluid and electrolyte balanceMaintain ph

Plasma proteins

Albumin-maintain osmotic pressure – 60% of plasma proteins

Globulins-36%Alpha and Beta–transporting lipids/fat

soluble vitaminsGamma globulins - type of antibody

Fibrinogen-4% blood coagulation

Gases and nutrients

Oxygen and Carbon - dioxide most important gases

NutrientsAmino acidsMonosaccharidesNucleotides

Lipids not soluble in water so they are surrounded by proteins for transport called lipoproteins. They are classified based on density (HDL, LDL)Plasma continued

Plasma cont’d

Nitrogenous substancesAmino acidsUreaUric acid

ElectrolytesSodium, potassium calcium,

magnesium, chloride, bicarbonate, phosphate, sulphate

Blood clot

Hemostasis – stoppage of bleeding

Stoppage of bleeding (3 steps)Blood vessel spasm-muscle in wall of vessel

contracts.Platelet plug formation-platelets stick to

edges of damaged blood vessels, forming net. Release serotonin (vasoconstrictor.) Most effective on small vessel.

Patients with leukemia have tendency to bleed because they have fewer platelets.

Blood coagulation-most effective means =hemostasis

Hemostasis

Steps in platelet plug formationSlide number: 2

Endothelial lining Collagen fiber

Erythrocyte

Break invessel wall

1

Platelet

Steps in platelet plug formationSlide number: 3

Endothelial lining Collagen fiber

Erythrocyte

Break invessel wall

1

Blood escapingthrough break

2

Platelet

12_12 Steps in platelet plug formationSlide number: 4

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Endothelial lining Collagen fiber

Erythrocyte

Break invessel wall

1

Blood escapingthrough break

2

Platelets adhereto each other,to end of brokenvessel, and toexposed collagen

3

Platelet

Steps in platelet plug formationSlide number: 5

Endothelial lining Collagen fiber

Erythrocyte

Break invessel wall

1

Blood escapingthrough break

2

Platelets adhereto each other,to end of brokenvessel, and toexposed collagen

3

Platelet plughelps controlblood loss

4

Platelet

Blood coagulation

How does blood clot

Blood groups and transfusions

Antigens - on erythrocytes

Antibodies - in blood plasma – attack things that don’t belongWrong blood

type = agglutination

ABO Group

Type AType BType ABType O

RH blood group

Rh factorRh positive and

Rh negativeErythroblastosis

fetalis