coagulation and inflammation

Question 1

what does tissue factor do

Answer 1

it triggers the clotting cascade

Question 2

what do anticoagulants and anti-platelets do

Answer 2

block calcium signals to spot them from activating

Question 3

what does antithrombin III do

Answer 3

it helps to stop the coagulation pathway from carrying on further down the blood vessesl

Question 4

what happens to the blood vessels when there is damage

Answer 4

• subendothelial lining is removed
• barrier stopping clotting cascade has gone
• platelets begin to bind

Question 5

how do platelets start to bind after damage to the vessel

Answer 5

bind to the subendothelial matric through collagen receptors

Question 6

what does reflex vasoconstriction do

Answer 6

reduces the blood flow to the damaged vessels

Question 7

why does reflex vasoconstriction occur

Answer 7

-endothelin release from endothelium vasoconstricts
- loss of NO causes smooth muscle cells to be disinhibited
- serotonin release maintains vasoconstriction

Question 8

what is primary haemostasis

Answer 8

the platelets plug the hole in the damaged vessel

Question 9

why does primary haemostasis occur

Answer 9

• platelets stick to subendothelial collagen by von Willebrand Factor

Question 10

what happens in a loss of von willebrand factor

Answer 10

causes bleeding disorders and platelets can’t bind to subendothelial layer

Question 11

how are platelets activated

Answer 11

adhesion via glycoproteins trigger their activation by a rise in cytosolic Ca concentration

Question 12

what happens once platelets bind

Answer 12

• positive feedback
• pathway triggers more platelets to bind

Question 13

what do activated platelets produces

Answer 13

• secretory vesicles/ granules released - ATP, ADP and serotonin
• produce thromboxane A2

Question 14

what do activated platelets trigger

Answer 14

conversion of glycoprotein IIb/IIIa into active form
- platelets can adhere to fibrogen to create a plug to restrict blood flow

Question 15

why are ADP antagonists used to treat for antiplatelets

Answer 15

• block the positive feedback loop
• stop the clotting you don’t want but don’t stop it fully

Question 16

what is immune thrombocytopenia

Answer 16

• bleeding disorder from a low platelet count
• cytotoxic T cells target own platelets
• more blood leaves in microvascular damage making small spots

Question 17

what is secondary haemostasis

Answer 17

fibrin production stabilises and strengthens the growing clot

Question 18

why is thrombin needed in secondary haemostasis

Answer 18

it cleaves fibrinogen to fibrin

Question 19

how does fibrin stabilise the clot

Answer 19

cross linking due to factor 13 increase strength, making an insoluble fibrin mesh to stop clot movement

Question 20

what does the extrinsic pathway do in clotting

Answer 20

it initiates coagulation

Question 21

how is excessive blood clotting prevented by fibrin

Answer 21

• circulating tissue factor bind to the platelet plasma membrane (calcium-dependent)
• helps localise all components of coagulation cascade to platelet surface

Question 22

when does fibrinogen do

Answer 22

helps the wall to contract to get endothelial wall build up to replace the platelets

Question 23

how does warfarin work

Answer 23

• inhibits vitamin K of clotting factors in the liver
• means platelets cant bind to platelets plasma membrane

Question 24

how does haemophilia A work

Answer 24

• factor VIII deficiency
• prevents normal production of tenase complex

Question 25

how is the clotting cascade ‘turned off’

Answer 25

• thrombin mediated
• protein C bind to surface of endothelial cell
• it binds and becomes activated and cleave factor 5 and 8a

Question 26

what is the triad of death

Answer 26

• coagulopathy
• acidosis
• hypothermia

Question 27

how does the triad of death

Answer 27

• fluid resuscitation dilutes coagulopathy
• loss bicarbonate you go into acidosis
• acidosis slows down the clotting cascade

Question 28

what causes systemic activation of coagulation

Answer 28

• pregnancy complications
• hyperthermia
• sepsis
• burns
• trauma
• cancer
• transfusion

Question 29

what happens in fibrinolysis

Answer 29

resolution of clot by breaking down fibrin

Question 30

how is fibrin broken down

Answer 30

• endothelial cells release tissue plasminogen activation
• thrombin activates protein C to disinhibit t-PA
• t-PA activates plasminogen
• plasmin then cleaves fibrin to break down clot

Question 31

what does recombinant tPA do

Answer 31

used to remove unwanted clots formed during a stroke

Question 32

what does TXA do

Answer 32

prevents heavy nose or menstrual bleeding following trauma or surgery

Question 33

what causes venous thrombosis

Answer 33

endothelial inflammation due to loss of blood flow triggering vWF

Question 34

how are white blood cells involved in acute inflammation

Answer 34

• inflammatory mediators triggered causing redness, heat and swelling
• more blood flow to area makes if read and warm

Question 35

why is the swelling in acute inflammation

Answer 35

• more filtration as intracellular junction broken down
• fluid and proteins can move faster causing swelling

Question 36

what does factor 12 trigger

Answer 36

1. 12 -> prekallikrein -> kallikrein -> joins HMW kininogen -> bradykinin (inflmation)
2. 12 -> prekallikrein -> kallikrein -> joins plasminogen -> plasmin

Question 37

what does serotonin cause

Answer 37

• vasodilation
• increased vascular permeability

Question 38

what does histamine cause

Answer 38

• vasodilation
• increased vascular permeability

Question 39

what do leukocytes and platelets cause

Answer 39

• PGD2 - vasodilation
• PGE2 - vasodilation and pain