CHAPTER 19 BLOOD

I. INTRODUCTION

A. CIRCULATION

arteries - from heart

smaller arteries

capillaries - delivery to cells - filtration

small veins - back to heart

larger veins

B. COMPOSITION OF BLOOD

1. connective tissue

free floating cells in liquid matrix

2. formed elements and plasma

3. plasma- with clotting proteins

out of body add anticoagulants- heparin

4. serum - remove clotting proteins

let blood clot and remove liquid = serum

5. cells:

a. erythrocyte - RBC

b. leukocyte - WBC

c. % RBC = hematocrit 45% normal

d. % WBC = <1%

e. % plasma = 55%

6. pH = 7.35-7.45

C. FUNCTIONS OF BLOOD

1. general: deliver and remove substances to/from cells

2. O₂, CO₂ , nutrients delivered, wastes removed

3. hormones

4. regulation of body temp

5. maintain BP by regulation of Blood volume

6. disease defenses

7. clotting with injury

II. ERYTHROCYTES

A. STRUCTURE

1. 7.5um line up single file in capillary

2. biconcave disc

3. 4-5million /mm³

4. mature - anucleated

5. hemoglobin (Hb)

a. 33% of cell

b. heme - 4 Fe contained in each Hb molecule

c. globin - globular protein

d. oxyhemoglobin - bright red with oxygen attached

e. deoxyhemoglobin - without oxygen - dark color

6. Carbon dioxide binds to globin portion

B. FORMATION

1. Hematopoiesis - process of making blood cells

2. occurs in red bone marrow

a. long bone, girdles in adults, most all bones in children

b. enters blood via capillary sinusoids (large

capillaries near site of production at marrow)

3. Erythropoietin

a. hormone produced largely by kidneys

b. stimulates RBC formation

4. Hemocytoblast

a. RBC and WBC both originate from this stem cell

5. Erythropoiesis - formation of RBC

a. hemocytoblast<- erythropoietin

erythroblast <- produce Hb

has nucleus, ribosome, ER

normoblast <- no more Hb made, anucleated

reticulocyte <- in blood with ER, ribosome

indication or rate of formation

erthrocyte <- loss of ER and ribosome

life span - 100-120 days

6. formation enhanced by:

a. oxygen delivery to tissue

b. oxygen tension in atmosphere - high altitude

produce more RBCs to deliver more oxygen

c. iron in diet

1. absorbed in GI tract

2. bound to plasma protein - transferrin

d. Vitamin B₁₂

1. required to produce RBCs

2. may be deficient in vegetarian diet

3. stomach mucosal cells may not produce

Intrinsic Factor to absorb it

a. injections required

C. REMOVAL OF OLD RBCs

1. Spleen

a. RBC graveyard

b. macrophages there break down and recycle

c. heme to bilirubin secreted in bile

and Fe reused

d. destruction balanced with formation

D. DISORDERS

1. Anemia

a. low oxygen carrying capacity

b. fatigued, pale

c. low oxygen, cells cannot make ATP

d. types:

1. hemorrhagic

2. hemolytic

3. aplastic (at Red bone marrow)

4. iron defeciency

5. pernicious (B12)

2. Genetic disorders - alters Hb molecule

a. Thalassemia

1. thin, pale RBCs

2. <2 million /mm³

3. Mediterrean ancestry

b. Sickle cell

1. changes shape of RBC

2. one amino acid change

3. not easy to pass capillary under certain

conditions- stress

4. microbe enters RBC in malaria and

ruptures it but not with the sickle

cell

5. found in descendents of African malaria

belt

3. Increased RBCs

a. polycythemia

1. normal physiological response to increased

altitude

2. 80% hematocrit may indicate bone marrow cancer

III LEUKOCYTES (WBC)

A. STRUCTURE

1. contains a nucleus and organelles

2. 4-11,000 / mm³

3. can squeeze through capillaries in

a process called- DIAPEDESIS

4. GRANULOCYTES all larger than RBCs

a. neutrophils

b. basophils

c. eosinophils

5. AGRANULOCYTES

a. lymphocytes (about size of RBC)

b. monocytes (much larger than RBC)

6. order from most to least

NLMEB

B. FUNCTION

1. fight invading microbes and infection

2. signaled to site of infection by

chemicals released

a. CHEMOTAXIS

1.movement of the cell in response

to a chemical signal

C. NEUTROPHILS

1. PMNs polymorphonuclear leucocytes

2. function:

a. PHAGOCYTOSIS of bacteria

3. # increases with bacterial infection

4. granules in cytoplasm neutral staining

5. many lobes of nucleus

6. in Differential WBC count: 40-60% of cells D. EOSINOPHILS

1. # increases with parasite infection (worms)

2. # increases with allergic reactions

3. granules in cytoplasm stain red

4. in Diff. WBC count : 1-4%

E. BASOPHILS

1. release histamine for inflammatory response

a. histamine is a mediator to increase capillary permeability and to vasodilate

2. in Diff. WBC count : <1%

F. LYMPHOCYTES

1. most are in lymphatic tissue

2. B cells - produce antibodies

3. T cells - foreign cell attack

4. # increases with viral infections and tumors

G. MONOCYTES

1. largest of WBC

2. mature into macrophages in tissues

3. increase with bacterial and parasite infection

4. macrophages function in PHAGOCYTOSIS

H. FORMATION

1. hematopoiesis - blood cell formation

2. leukopoiesis - WBC formation

a. stimulated by CSF (colony stimulating factors) many possible substances

1. interleukin 3

3. HEMOCYTOBLAST (stem cell)

{myeloblast} [lymphoblast]

{Eosino. Neutro. Baso. monoblast } [lymphocyte]

I. DISORDERS

1. leukopenia

a.low WBC production

b. can be induced by cancer drugs

2. Leukemia

a. cancer cells impair normal function of

bone marrow

b. bone marrow transplants

3. infectious mononucleosis

a. virus - Eipstein-Barr

b. increase # monocytes, abnormal lymphoctes

c. tired;chronic sore throat;low-grade fever

III. PLATELETS

A. STRUCTURE

1. oval disk

2. 200,000-300,000/mm³

3. fragment of cell

B. FORMATION

1. from HEMOCYTOBLAST

myeloid stem cell

megakaryoblast (ruptures)

platelet ( also called (thrombocytes)

C. FUNCTIONS

1. blood coagulation role

2. HEMOSTASIS

a. stoppage of blood flow

b. platelets form plug for clot to attach

3. releases substances to initiate coagulation

IV. PLASMA

A. FUNCTION

1. Transport medium

2. contains clotting proteins

3. proteins to exert osmotic pressure to prevent water from leaving plasma ant entering tissues

B. COMPOSITION

1. PROTEINS

a. albumin

1. major plasma protein

2. keeps high osmotic pressure

3. substances can bind and be transported

on albumin molecule

b. globulins

1. larger molecules

2. bind substances: lipids, metals, Vitamins

3. gamma globulins - antibodies

c. clotting proteins

2. ELECTROLYTES

a. Na

b. K

c. Cl

d. glucose

3. WATER (90%)

V. HEMOSTASIS

A. STAGES - GENERAL

1. vasoconstriction

a. decreases blood flow

2. platelet plug formation

a. release of thromboxane A2; PF3

b, more platelets attracted

3. coagulation

a. gel formed

b. prothrombin-->thrombin

c. thrombin catalyzes

fibrinogen --> fibrin

B. CASCADE OF ACTIVATION

1. factors in plasma activated to activate next step

in a required sequence

2. INTRINSIC PATHWAY - INITIATED BY BLOOD FACTORS

PLATELETS (XII -> ACT. XII)

(XI-> XI)

(IX->IX)

CALCIUM,PF3 (VIII ->VIII COMPLEX)

X -(PROTHROMBIN ACTIVATOR)

PROTHROMBIN -> THROMBIN

3. EXTRINSIC PATHWAY

ACTIVATED BY TISSUE FACTOR RELEASED WITH INJURY

4. COMMON PATHWAY

C. Clot retraction

1. contraction of platelets

2. fibrinolysis - removes clot after healing

D. Anticoagulants

1. heparin

a. produced by endothelial cells

b. antithrombin III prevents thrombin activation

2. aspirin

3. cumarin

E. DISORDERS

1. Hemophilias

a. clotting factors absent

b. Type A, B

2. Abnormat Clot formation

a. thrombus

1. clot in an unbroken vessel

2. results in lack of oxygen to tissue

b. embolus

1. clot moves away from vessel wall and

enters bloodstream until trapped

2. stroke

F. BLOOD GROUPS

1. RBCs have self antigens (agglutinogens)

2. Antibodies (agglutinins) in blood

3. A,B,AB,O

a. type is the antigen on RBC

b. O has no antigens

4. Important in blood transfusions

5. type A blood has type B antibody

6. complete the chart:

BLOOD TYPE ANTIGEN ANTIBODY CAN RECEIVE

A

B

AB

O

7. Transfusion reaction

a. antigen complexes with antibody

b. causes agglutination (clumping) and

lysis of RBC

c. donor RBC attacked by antibody in

recepients blood

8. Rh factors

a. a cell surface antigen

1. present +

2. absent -

b. problem when mother is Rh- and

does not have antigen (or antibody)

c. first pregnancy is

Rh+ baby and RH- mother may be exposed via

placenta to baby's blood and make

antibodies

d. no affect

e. second pregnancy

f. antibodies complex with fetus' Rh+ RBCs

and is born with hemolytic disease of

newborne

g. prevent by injection of RhoGAM

after birth or miscarriage to mother

1. anti-Rh agglutinins (antibodies)

block mothers immune response