Blood 8 Flashcards
What does Aspirin cause?
Irreversible inhibition of COX-1 and COX-2
What gives rise to Arachidonic Acid?
The phospholipid membranes of various cells
What happens when Arachidonic Acid is influenced by COX-1?
It can be converted to Thromboxane A2 (TXA2)
What happens when Arachidonic Acid is influenced by COX-2?
It can be converted to Prostacyclin
Where is COX-1 found?
In platelets
Where is COX-2 found?
In endothelial cells
What does Thromboxane A2 do (TXA2)?
Causes vasoconstriction and increased platelet aggregation
What does Prostacyclin do?
Dilates blood vessels and decreases platelet aggregation. Is anti-hemostatic
What does Aspirin have a stronger inhibitory effect on?
The COX-1 pathway that produces TXA2
What does the COX-1 pathway produce?
TXA2
What does the COX-2 Pathway produce?
Prostacyclin
What is the net effect of aspirin?
It dilates blood vessels and decreases platelet aggregation through by inhibiting the COX-1 pathway
Why is blood clotting necessary?
Because vasoconstriction and Platelet plug formation may not be effective enough
In a blood clot, what do the blood cells get trapped in?
A network of protein called fibrin
What does fibrin do in blood clotting?
Forms a net in the area of damage and traps cells that are present in the blood to prevent blood loss
Why do we need to produce fibrin from a precursor?
Because it is the main component of blood clots and we don’t need it all the time
What is the soluble Fibrin precursor?
Fibrinogen
When and Where is Fibrinogen present?
It is present all the time in the plasma
Which enzyme catalyzes Fibrinogen to Fibrin?
Thrombin
Why can’t we have Thrombin consistently present in the blood?
Because it would activate fibrinogen to fibrin
What is the Precursor molecule to Thrombin?
Prothrombin
What converts Prothrombin to Thrombin?
Prothrombinase
How many plasma clotting factors are there?
12
What is Plasma clotting factor I?
Fibrinogen
