Perf Tech Test 6

Question 1

Arterial vs Venous clotting response

Answer 1

arterial- 1) platelets 2) forming fibrinogen

venous 1) thrombin generation

Question 2

the 2 clotting factor types

Answer 2

proenzyme (become enzyme when activated- also called zymogens)
procofactors (become cofactors- help something else become activated)

Question 3

Platelet Aggregation

Answer 3

• accelerates local process
• receptor site for factors
• releases factors
• provides negative charge surface

Question 4

Coagulation Cascade

Answer 4

series of proteolytic reactions that lead to fibrin clot

Question 5

Coagulation Cascade 3 Pathways

Answer 5

1) intrinsic- blood reacts with stuff (collagen, membrane)
- activated partial thromboplastin time (aPTT)
2) extrinsic- release of tissue factor and reacts with blood
- prothrombin time (PT)
3) common pathway- production of thrombin and fibrin
- PT

Question 6

Coagulation Cascade Pros and Cons

Answer 6

pros- understand Ca dependent, can do in lab

con- wrong about intrinsic/extrinsic independence, no fluid moving/no interactions

Question 7

Cell Based Model

Answer 7

thrombin generation

1) Initiation- on TF bearing cell
2) Amplification- platelets/cofactors active
3) Propagation- make lots of thrombin (thrombin burst) to make fibrin clot
4) Clot formation

Question 8

Platelet Adhesion

Answer 8

vWf held in place by subednothelial collagen
GPIb binds to vWf, but not very strong
this causes transmembrane signaling

Question 9

Platelet Activation

Answer 9

• GPIIb/IIIa + vWf= secure platelet on subendo
• GPIa/IIa binds to collagen on subendo
• GPIV also binds to collagen

Question 10

Platelet Activation Goals

Answer 10

• recuite
• vasoconstrict
• matrix
• acceleration of fibrin
• protect form fibrinolysis

Question 11

Recruitment of Additional Platelets

Answer 11

• these come from within platelets
  1) thromboxane A2 (TXA2)- platelet agonist and constrictor (cyclooxyrgenase cleaves arachidonic)
  2) serotonin- agonist/constrictor
  3) ADP- agonist

Question 12

Platelet Plug

Answer 12

GPIIb/IIIa + Ca binds to fibrinogen (or vWf)- forms bonds between multiple platelets

Question 13

4 Anticoagulants that helps with Termination (preventers spreading of clot)

Answer 13

TF, Protein C, Protein S and Antithrombin II

Question 14

TFPI

Answer 14

tissue factor pathway inhibitor

- forms a 4 part complex= TF, VIIa, Xa, TFPI= inactivates extrinsic tenase complex (“priming thrombin”)

Question 15

Protein C and S

Answer 15

inactivate Va and VIIIa

• vitamin K dependent
• activated by thrombin and Protein S

Question 16

ATIII

Answer 16

antithrombin III

• inhibits thrombin (IXa, Xa, XIa, XIIa)
• HEPARIN helps ATIII to prevent clotting

Question 17

Things that convert plasminogen to plasmin

Answer 17

• uPA (drug), tPA (tissue-type plasminogen activator), XIa, XIIa, Kallikrein

Question 18

Endogenous Anticoagulants

Answer 18

endothelial releases NO (dilate) and prostacyclin/PGI2 (inhibits platelet aggregation) and ADPase (inactivates platelets)

Question 19

5 things that cause bleeding

Answer 19

1) mechanical (proline insufficiency- surgeon mess up)
2) insufficient fibrin formation
3) insufficient clot integrity
4) insufficient clot adhesion
5) fibrinolysis