Blood Clotting Pathways.

Question 1

give examples of trauma

Answer 1

injections surgical incision tooth extractions

Question 2

what are the 3 major steps in haemostasis?

Answer 2

1. Vascular Spasm
2. Formation of Platelet Plug
3. Blood coagulation (clotting)

Question 3

3 reasons why must haemostasis controlled?

Answer 3

1. To avoid inappropriate clot formation
2. Clots must be eventually degraded
3. clots are temporary solution

Question 4

describe vacular spasms after injury?

which to products mediate this process

Answer 4

vasoconstriction of blood vessels after injury:

muscle cells contract which reduces blood flow to limit blood loss

opposing endothelial surfaces are pressed together and adhrere on contact

serotonin and thromboxane

Question 5

name 2 vasodilator ?

Answer 5

prostacyclin (prostaglandin I₂)

nitric oxide

Question 6

Platelets are also refer to as ?

they are produced by which cell ?

what feature to platelets have?

Answer 6

thrombocytes

Megakaryocytes

energy generating organelles but no nuclei

Question 7

what allows platelets to contract ?

Answer 7

highly concentrated actin and myosin

Question 8

what 4 factors activate platelets?

Answer 8

1. ADP
2. collagen
3. Thrombin
4. Platelet activating factor (phospholipid)

Question 9

what happens to platelets when they are activated?

Answer 9

1. changing shape disc to sphere with pseudopodia
   
   1. allowing it to aggregate and coagulant activity
2. granules compounds involved in haemostasis=
   
   1. ADP/ Serotonin/ fibronectin and von willebrand factor (vWF)
3. aggregate
4. adhere to vessel wall
5. synthesis thrombane

Question 10

how is a platelet plug formed after activation?

Answer 10

Adhesion to the vessel wall at the site of injury

Platelets aggregate and build up on an occulsive platelet mass forming a PRIMARY HAEMOSTATIC PLUG

This can be washed away by blood flow when vasoconstriction decreases.

It is stablised by fibrin

Question 11

where is von Willebrand Factor produced from ?

Answer 11

platelets and endothelial cells

Question 12

what are the 2 platelet and platelet related bleeding disorders?

Answer 12

1. von Willebran disease- autosomal disease affecting vWF
2. less common disease that affects the receptors found in platelet membrane- involved in adhesion and aggregation.

Question 13

anti platelelet drugs are used to treat …

through…

such drugs include

Answer 13

arterial thrombosis- blood clotting in the vessel

through decreasing platelet aggregation and inhibit thrombus formation

Asprin/ Platelet receptor antagnosists /Platelet ADP receptor antagonists.

Question 14

what is the role of collagen

Answer 14

structure and function of small blood vessels

Question 15

what is aquired and cogenital disease

Answer 15

cogenital is something u were born with and aquired it something u develop after birth.

Question 16

name 1 cogenital disease for excessive bleeding

name 2 aquired disorders for excessive bleeding

both are linked to collagen

Answer 16

1) Ehlers Dnalos syndrome

1. Vitamin C deficiency
2. excessive glucacorticoides (steroid hormones)

Question 17

what do blood coagulation factors form when they interact in

1. small vessels
2. and arteries and viens

Answer 17

1. secondary fibrin rich haemostatic plug
2. secondary thrombus

Question 18

intrinsic pathways are activated by?

Answer 18

exposure of flowing blood to sub endothelial collagen exposed by vessel damage

Question 19

extrinsic pathway are activated by

Answer 19

tissue damage which exposes flowing blood to proteins called tissue factors

Question 20

what is the feature of the final common pathway

Answer 20

fibrinogen is converted to fibrin

Question 21

how is a fibrin clot formed ?

Answer 21

through the intertaction between intrinsic/ extrinsic and final common pathways

Question 22

what is the role of a clot on top of a platelet plug?

Answer 22

strenghtens the plug and reinforces the seal

Question 23

fibrin:

1. features
2. role
3. arises ?

Answer 23

1. insoluble, thread like molecule
2. forms a loose meash that traps blood cells
3. genertated by fibrinogen which is a soluble plasma protein synthesised by liver

Question 24

what are the 2 roles of thrombin ?

Answer 24

1. catalyses conversion of fibrongen to fibrin
2. activates factor XIII

Question 25

What does factor XIII do ?

Answer 25

catalyses the cross links between adjecent fibrin