Coagulation cascade and Fibrinolysis Flashcards

1
Q

What is tissue facotr?

A

Transmembrane protein

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2
Q

Where is TF located?

A

Plasma membrane of adventitial fibroblasts

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3
Q

Which blood clotting factor binds to TF?

A

VII

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4
Q

What does the TF/VIIa complex activate?

A

Clotting factors IX and X by proteolysis

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5
Q

What does the TF mechanism ensure?

A

Spatially constrained clotting at sites of vascular damage

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6
Q

What does the initial thrombin lead to?

A

Amplification of thrombin generation by activating factor XI, co-factor VIII and V and platelets

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7
Q

What is the enzymatic activity of Xa enhanced by?

A

Va

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8
Q

What does the assembley of IXa/VIIIA/X require?

A

Binding to platelet membranes

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9
Q

What is the fibrin clot dissolved by?

A

Plasmin

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10
Q

What is clot formation balanced by?

A

Clot degradation

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11
Q

What system balances clot formation and clot degradation?

A

Fibrinolytic system

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12
Q

What proenzyme does plasma contain?

A

plasminogen

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13
Q

What 2 things does plasminogen bind to?

A

Fibrin and to cell surfaces

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14
Q

What do plasminogen activators convert plasminogen to?

A

Enzymatically active plasmin

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15
Q

What is plasmin?

A

Serine protease that digests fibrinogen and fibrin thereby dissolving clot

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16
Q

What do endothelial cells continuously release?

A

Tissue plasminogen activator (tPA)

17
Q

How is tPA activated?

A

Binding to fibrin clots

18
Q

What is tPA’s major substrate?

A

Plasminogen

19
Q

What does partial degradation of fibrin by plasmin expose?

A

Further tPA binding sites on fibrin and plasmin activates tPA slightly by proteolysis

20
Q

What does tPA binding to fibrin initiate?

A

Local activation of fibrinolysis

21
Q

What are plasminogen activator inhibitors?

A

Serine protease inhibitors that block function of tPA

22
Q

Define thrombosis.

A

Clot formation inside vessels

23
Q

Where does venous thrombosis occur?

A

Lower limbs

24
Q

How do thrombus fragments reach the heart?

A

Carried by bloodstream through right heart into pulmonary arteries

25
What do thrombus fragments cause?
Occlude blood flow through the lung leading to immediate sudden death
26
What do arterial thrombosis lead to?
Local tissue damage depending on artery/organ