haemostasis

Question 1

define haemostasis

Answer 1

cessation of bleeding

Question 2

define a harmorrhage

Answer 2

excessive flow of blood

Question 3

what happens in normal haemostasis?

Answer 3

when collagen is exposed during injury of the vessels, platelets clump together stopping blood flow

Question 4

what are te five steps of haemostasis

Answer 4

vessel spasm
platelet plug formation
coagulation
clot retraction
fibrinolysis

Question 5

what happens in the vessel spasm step?

Answer 5

vasoconstriction
triggers pain receptors and reflex of constriction
slows the amount of blood
very ra[id response

Question 6

what happens to platelets during activation

Answer 6

send out protrusions called pseudopodia

Question 7

what are the types of protrusions made by platelets during activation

Answer 7

filopodia: stringy tenticles to establish platelet contact
lamellipodia: flat thin membrane giving coverage

Question 8

what happens during platelet plug formation?

Answer 8

platelets detect actiating molecules using proteins o their surface
activatory molecules bind to the receptor signal causing a cascade
signal transmitted intocells activating platelet

Question 9

what are strong activators of platelets

Answer 9

collagen and thrombin

Question 10

what is a weak activator of platelets

Answer 10

ADP, adrenaline
platelet activating facyor
vasopressin
serotonin

Question 11

4 steps of platelet plug formation

Answer 11

adhesion to site of damage
activation
secretion
aggregation

Question 12

what are found inside platelets

Answer 12

vesicles/granules

alpha and dense graules

Question 13

what causes platelets to stick to collagen?

Answer 13

vWF

transient tethering

Question 14

what is vWF?

Answer 14

plasma protein which sticks to collagen and platelets

weak interaction so just slows patelet down so it can make other interactions

Question 15

what does vWF allow to bind to the platelet

Answer 15

GP6 which triggers the signal cascasde

Question 16

what effects does GP6 have?

Answer 16

shape change
alpha 2B 3 receptor changes shape
secretion

Question 17

what happens during activation in plug formation

Answer 17

the signal cascase: changes shape of the platelet and trggers secreton

Question 18

what is a dense graule

Answer 18

ADP and seronin

Question 19

what is an alpha granule

Answer 19

fibrinogen

vWF

Question 20

what happens during secretion?

Answer 20

graunules inside the platelet released
contense spilled
these activate other platelets and act back on the same platelet
positive feedback

Question 21

what is the aggregation step of plug formation?

Answer 21

receptor alpha2B3 changes to be open

fibrinogen binds clumping the platelets together

Question 22

what is fibrinogen used for?

Answer 22

to bind platelets together

Question 23

what regulates platelets in health?

Answer 23

endothelium produced chemicals to keep platlets calm
PGI2
NO

Question 24

what does loss of health endotheliam causee>

Answer 24

chemical inhibitors to be lost and thus the platelets become activated

Question 25

what is coagulation?

Answer 25

process in which the fluid blood is converted into a gelatinous clot

Question 26

what happens during coagulation

Answer 26

platelet plug covered to make it more stable red and white cells trapped and stringy strands/ filaments made and fibrin accumulates jelly clot now

Question 27

what is fibrin?

Answer 27

protein polymer with lots of subunits | monomer is fibrinogen

Question 28

what makes fibrin?

Answer 28

monomers of fibrinogen stick together to make fibron

Question 29

what converts fibrin to fibrinogen?

Answer 29

thrombin

Question 30

what is thrombin?

Answer 30

converts monomer fibrinogen to polymer fibrin poretease not present all the time

Question 31

what is fibrinogen?

Answer 31

sticks to fibrin and activated platelets receptors to form the plug

Question 32

what is fibrinogen?

Answer 32

sticks to fibrin and activated platelets receptors to form the plug

Question 33

what can lead to th conversion of prothromin to thrombin?

Answer 33

intrinsic and extrinsic

Question 34

how does the intrinsic pathway for thrombin work>

Answer 34

everything is already int he blood stimulated in the contact of blood on collagen/charged surfaces platets activated on exposure to colalgen and release phopholipids

Question 35

what is prothrombin

Answer 35

present in the blood all the time | version of throbin thats safer

Question 36

how does the extrinsic pathway for thrombin work?

Answer 36

cellular element needed stimulated by tisseu factor called thromboplastin damaged tissues release this

Question 37

what is factor 10 xa

Answer 37

converts prothrombin to thrombin

Question 38

what does X and XA mean for clotting factors

Answer 38

X means inactive | Xa means active

Question 39

what causes haemoaphillia?

Answer 39

missing factor 8

Question 40

what is the common pathway of clotting?

Answer 40

where the extrinsic and intrinsic pathways come together and are the same from then onwards

Question 41

how does positive feddback control clotting?

Answer 41

strong factos | cross talk between the pathways

Question 42

how does negative feedback control clotting?

Answer 42

antithrombin 3 inhibtiing thrombin | plasminogen breaking clots down again

Question 43

what is clot retraction

Answer 43

clot shrinkage about 20-30 mins after injury | pushes liquid out and pulls wound together for healing

Question 44

`why is fibrinolysis needed?

Answer 44

blood flow must be established for permanent tissue repiar to take place the clot is disolved

Question 45

what enzyme breaks down fibrin and the clot

Answer 45

plasmin

Question 46

what converts plasminogen to plasmin?

Answer 46

enzymes called plasminogen actvators

Question 47

example of a plasminogen actvator?

Answer 47

TPAL | tissue-type plasminogen activator which comes from healthy endothelium to break down the clots

Question 48

wat strops blood in circulation from clotting?

Answer 48

- healthy endothelium - clotting factors inactive form - flow carries clotting factors away - inhibition of clotting factors - fibrinolysis

Question 49

what are the patholies of platelet plug formation?

Answer 49

arterial thrombosis mycardial infarction ischaemic stroke PAD

Question 50

patholigies of coagulation

Answer 50

venous thromobisis | DVT

Question 51

what causes arteial thrombosis?

Answer 51

inappropraite activation of platelets in artiers | eg rupture of altherloscloris

Question 52

how can althersclorisi cause arterial thrombosis?

Answer 52

fat is depositied into arties and this can break and leak out this activates the platelets and a clot is formed in the vessel

Question 53

what causes venousthrombosis

Answer 53

inappropriate activation of coaulation in the veins

Question 54

wat causes inappropriate activation of coagulation in the veins?

Answer 54

virchows traid: stasis endothelium damage hypercoaguability

Question 55

why is venous thromboisis bad?

Answer 55

a bit of the DVT can break off in an embolism and travel to somewhere more dangerous such as lungs or heart

Question 56

how is venous thrombosis treated?

Answer 56

anticoagulant drugs

Question 57

how is arterial thrombosis treated?

Answer 57

anti-platelet drugs

Question 58

what is a fibrinoytic drug used for?

Answer 58

disolving clots

Question 59

exa,mple of an antiplatelet drug

Answer 59

asprin

Question 60

what does asprin do

Answer 60

inhibits platele function and artial thrombosis | inhibits COX making thromboxane A2

Question 61

what does \COX do?

Answer 61

converts tothromxane A2

Question 62

example of an anticoagulant drug? e

Answer 62

warfrainhat does warfaein do?

Question 63

what does warfrain do?

Answer 63

clotting factor made in the liver | inhibits cycling of vitK which is needed to make more clotting factors

Question 64

example of a fibrinolytic drug?

Answer 64

tPA

Question 65

what is tPA

Answer 65

synthetic enyme to convert plasminogen to plasmin to break down the clot

Question 66

how is arterial thrombosis treated/prevented

Answer 66

antiplatelet drugs of asprin

Question 67

how si venous thromosis treated/prevetned

Answer 67

antiocoagulant drugs of warfarin

Question 68

how are clots dealt with and treated?

Answer 68

fibrinolytic drugs auch as tPA