Part 3 Hemostasis Hemostasis stoppage of blood flow

Part 3

Hemostasis

Hemostasis – stoppage of blood flow 3 Stages 1. Vascular Spasms – • immediate response to vessel injury • response to pain

2. Platelet Plug Formation • Vessel endothelium ruptures and collagen fibers are exposed • Platelets swell forming sticky processes and release chemicals • Chemicals may enhance spasm or attract more platelets to area (pos. feedback) • Loose knit plug formed

3. Clot Formation or Coagulation • Thromboplastin (from platelets and injured cells) acts as a catalyst • Catalyst causes several intermediate steps which cause • Formation of thrombin enzyme • Thrombin causes fibrinogen to change to fibrin which forms strings • Cells attach to fibrin forming a clot

Thrombus

Thrombus • clot in undamaged vessel • may occlude and cause tissue death

• free floating thrombus = embolism

• caused by: – roughening of vessel due to inflammation – burns – Arteriosclerosis – reduced blood flow in bed ridden patients • treat with anticoagulants

Transfusions and Blood Loss

Transfusions and Blood Loss • 30% or more loss can be fatal • 1/10 or less, no problem

• incompatible transfusion can be fatal • some blood factors cause little or no reaction and are used mainly for genetic and legal studies • ABO Blood Groups and Rh do cause reactions (hemolysis and clumping)

• ABO Blood Groups and Rh do cause reactions (hemolysis and clumping)

Blood Typing

Type A Type B Type AB Type O

Blood type is based on the presence of 2 major antigens in RBC membranes-- A and B Blood type A B A&B Neither A or B Antigen A B AB O Antibody anti-B anti-A no anti body anti-A and anti-B Antigen protein on the surface of a RBC membrane Antibody proteins made by lymphocytes in plasma which are made in response to the presence of antigens. They attack foreign antigens, which result in clumping = agglutination

Human Blood Groups • Antigen: Antigen foreign substance that immune system recognizes • Antibodies: Antibodies Y-shaped proteins secreted by WBC’s that attach to antigens • Agglutination: Agglutination clumping caused by antibodies binding to antigens on RBCs • RBC surface proteins: • A antigen • B antigen • Rh antigen

Type A b b b b

Type B a a a a

Type O a b a a b b

Type AB

ABO Blood Groups 42% • • 12% 3% 43% Type A: has A antigen on surface of RBC Type B: has B antigen Type AB: has both A & B antigens Type O: has no antigens on surface

O = Universal Donor AB = Universal Recipient

ABO Blood Groups Table 17. 4

Blood being tested Type AB (contains agglutinogens A and B; agglutinates with both sera) Anti-A Serum Anti-B RBCs Type A (contains agglutinogen A; agglutinates with anti-A) Type B (contains agglutinogen B; agglutinates with anti-B) Type O (contains no agglutinogens; does not agglutinate with either serum) Figure 17. 16

Blood Typing Blood type being tested RBC agglutinogens Serum Reaction Anti-A Anti-B AB A and B + + B B – + A A + – O None – –

ABO Blood Types Phenotype Genotype O A or I A i B or I B i AB i i IA IA I B IA IB

Punnett square Type A and Type B cross IA IA IB i I AI B I Ai

Blood Typing Analysis • Blood sample mixed with 3 antibodies • If blood clumps, antigens are present • If no clumps, no antigens are present Anti-A antibody test Anti-B antibody test Rh antibody test

• Rh antigen found on RBC’s in Rhesus monkeys (1940) Rh+ : 85% Rh- : 15%

Rh Factor and Pregnancy RH+ indicates protein RH- indicates no protein

Rh Factor and Pregnancy Rh+ mother w/Rh- baby– no problem Rh- mother w/Rh+ baby– problem Rh- mother w/Rh- father– no problem Rh- mother w/Rh- baby-- no problem Rho. GAM used @ 28 weeks

Rh Factor • in USA approximately 85% are Rh + and 15% are Rh – • after exposure to +, a - baby will build antibodies and a second exposure can result in clumping – usually less severe than AB reactions • pos. babies in a neg. mother were a problem • now mother given a shot a birth to block immune response

Volume Emergencies • transfuse plasma because no typing needed and volume increases fast

1. 2. 3. 4. 5. 6. 7. 8. INQUIRY What is an erythrocyte, leukocyte, and thrombocyte? What 2 things do red cells lack compared to white cells? What dietary component is needed for the production of red blood cells? The largest cells in the blood that leave the bloodstream to become macrophages are ____. In an acute infection, the white cell count would show as ______. Erythroblastosis fetalis , also known as hemolytic newborn disease, occurs in ____ mothers carrying ____ fetuses. What antigens and antibodies found on AB red cells? In a transfusion, what type blood can you give a type O person?