blood ii Flashcards
1
Q
Coagulation Part 1: Intrinsic
A
- Triggered by negatively charged surfaces (activated platelets, collagen, glass)
- uses factors present within blood
- platelets provide site for mobilization of factors
- XII –> XI –> IX (with help from Ca and VII) –> VIII (with help from PF3 from platelets) –> IX/VIII activate X–> activates V
-Ca + PF3 + X+V = prothrombinase
2
Q
Coagulation Part 1: Extrinsic
A
- Triggered by exposure to Tissue factor or factor III
- TF + Ca activates VII
- TF/VII activates X
- X activates V
- Ca + PF3 + X + V = prothrombinase
3
Q
Coagulation 2
A
Prothrombin activator catalyzes transformaiton of prothrombin to active enzyme thrombin
-once prothrombin activator is formed, clot forms in 10-15 secs
4
Q
Coagulation 3
A
Thrombin converts soluble fibrinogen to fibrin
- fibrin strands form structural basis of clot
- fibrin makes plasma gel-like trap for formed elements
- Thrombin with Ca activates factor XIII which cross links fibrin and stabilizes clot
5
Q
Clot retraction
A
- stabilizes clot
- actin and myosin in platelets contract within 30-60 mins
- contraction pulls on fibrin strands, squeezing serum from clots
- draws ruptured blood vessel edges together
6
Q
vessel repair
A
- vessel is healing as clot retraction occurs
- platelet derived growth factor stimulates division of smooth muscle cells and fibroblasts to rebuild blood vessel wall
- Vascular endothelial growth factor stimulates endothelial cells to multiply and restore endothelial lining
7
Q
Fibrinolysis
A
- removes unneeded clots after healing
- begins within 2 days - continues for several
- plasminogen in clot is converted to plasmin by tissue plasminogen activator, factor XII and thrombin
- Plasmin is fibrin-digesting enzyme
8
Q
Factors limiting clot growth or formation
A
- swift removal and dilution of clotting factors
- inhibition of activated clotting factors
- Antithrombin III inactivates unbound thrombin
- Heparin in basophils enhances antithrombin III
9
Q
Preventing platelet adhesion
A
- smooth endothelium of blood vessels prevents platelets from clinging
- antithrombic substances Nitric oxide and prostacyclin secreted byendothelial cells
- vit E quinone acts as anticoagulant
10
Q
Disorders of hemostasis
A
- thromboembolic disorders = undesireable clot formation
- Bleeding disorders = prevention of normal clot formation
- Disseminated intravascular coagulation (DIC) = clotting factors get used up where they’re not needed, so can’t be used when they are needed
11
Q
Agglutinogens vs agglutinins
A
antigens (A, B)
antibodies
12
Q
how many antigens on RBCs?
A
30
13
Q
how many Rh agglutinogens?
-which is most common?
A
52
C, D, and E
(Rh = D)
85% americans are +
14
Q
Hemolytic disease of the newborn
A
“erythroblastosis fetalis”
- Rh- mom has Rh positive baby and develops antibodies for Rh
- mom has another Rh+ baby and her antibodies attack the baby’s blood
- RhoGAM stops mom from making anti Rh antibodies
