Haemostasis Flashcards

1
Q

What are the 5 major steps of haemostasis?

A

Vascular spasm, formation of a platelet plug, conversion to a clot by reinforcement with fibrin, tissue repair and gradual removal of clot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the role of ADP in platelet plug formation?

A

Sticky platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the role of serotonin in plug formation?

A

Vasoconstrictor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the role of thromboxane A2 in plug formation?

A

Vasoconstrictor and activates platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is triggered when the platelet plug is formed?

A

Coagulation cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the intrinsic pathway of the coagulation cascade?

A

XII–>XIIa
XI–>XIa
IX–>IXa
X-Xa via VIIIa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the extrinsic cascade? (trauma)

A

VII–>VIIa
X–>Xa via tissue factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the final common pathway?

A

Xa via Va converts prothrombin to thrombin which converts fibrinogen to fibrin which is acted on by XIII1 to form a cross-linked fibrin clot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where are the 4 calcium/vitamin K dependent sites of the coagulation cascade?

A

IX–>IXa
VIIIa and tissue factor for X–>Xa
Va for prothrombin to thrombin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the role of prostacyclin in clotting?

A

Inhibits adhesion and aggregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the role of nitric oxide in clotting?

A

Inhibits platelet adhesion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the role of the liver in clotting?

A

Synthesises bile salts for the absorption of vit K in the GI tract and synthesises clotting factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What enzyme breaks down a clot?

A

Plasmin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does antithrombin work?

A

Inactivates thrombin and inactivates factors Xa and IXa, anticoagulant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What conditions lead to excessive bleeding?

A

Clotting defects and platelet deficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What conditions lead to thrombus formation?

A

Atherosclerosis, imbalance in clotting mechanism and septicemic shock