haemostaisis

Question 1

haemostais

Answer 1

: cessation of bleeding (right place, right time).
ie. At site of injury, when risk of blood loss.
PHYSIOLOGY

Question 2

Thrombosis

Answer 2

inappropriate activation of platelets or coagulation (wrong place, wrong time).

Question 3

bleeding

Answer 3

insufficient activation of platlets or coagulation

defects of quanitity or function

Question 4

what are the 5 steps in haemostasis

Answer 4

vessel spasm
platlet plug formation
coagulation
clot retraction
clot dissolution

Question 5

outline normal haemstasis

Answer 5

• injury to the vessel wall exposes the subendothelium which includes collagens
• circulating platelets come into contact with the collagens they become activated and form a platelet plug.
• Coagulation is the process where fibrin (stringy stuff) is formed to bind all the cells together into a more stable clot.

Question 6

vessel spasm

Answer 6

vessel damaged exposing collagen
pain receptor reflex
releasing meditors of vasoconsriction
reduce blood flow through

Question 7

mediators of vessel spasm

Answer 7

thromboxane A2
endothelin
angiotensin

Question 8

describe platelets

Answer 8

small anucleate fragments frrom megakaryocytes

Question 9

steps in platelet plug formation

Answer 9

adhesion, activation, secretion and aggregaton

Question 10

process of platelt plug formation

Answer 10

At sites of damage the collagens are exposed.

• vWF i bind to both the collagen AND to the GPIb complex on the surface of platelets.
• This isn’t very strong, so just slows the platelet down rather than stopping it.
• The receptor GPVI is then able to bind collagen triggering a signalling cascade

Question 11

results of the signalling cascase of granules in platlet plug formation

Answer 11

The granules are secreted, releasing their contents to further activate nearby platelets.
The fibrinogen is converted from a low affinity state to a high affinity state (more able to bind fibrinogen).
The fibrinogen receptor is now able to bind to fibrinogen, cross-linking platelets together to form a platelet plug.

Question 12

platelet agonists

Answer 12

collagen and thrombin

Question 13

weak platler agonists

Answer 13

ADP

adrenaline

Question 14

negative regulation of platelets

Answer 14

Prostacyclin and NO are produced by healthy endothelium ie at sites where we don’t want platelet activation to occur

Question 15

coagulation step of haemostasis

Answer 15

fluid blood becomes gelatinous clot

polyermisation of fibrin involved

Question 16

role of thrombin

Answer 16

enzyme
catalyses conversion of fibrinogen to fibrin
generated from prothrombin at sites of tissue injury to help with coagulation

Question 17

intrinsic pathway of coagulation

Answer 17

exposed collagen activated F12

Question 18

extrinsic pathway

Answer 18

damaged tissue released tissue thromboplastin/tissue fctor

Question 19

clot dissolution

Answer 19

fibrinolysis

Question 20

how does fibrinolysis occur

Answer 20

plasminogen converted to plasminwhich disolves the clot

Question 21

plasminogen

Answer 21

activated by thrombin which comes from damaged tissue

is convereted into plasmin which dislves fibrin

Question 22

what can stop blood in circulation from clotting

Answer 22

inhibition of platelet function by healthy endothelium
inactive clotting factors
blood blow carring away factors
inhibitor factors
fibrinolysis

Question 23

low factor 8

Answer 23

haemophillia

leads to bleeding

Question 24

arterial thrombosis

Answer 24

ltherlosclotic plaques rupture triggering platlers to stick together

Question 25

venous thrombosis

Answer 25

deficiency in inhibitors fr coagulation cascade | found in DVT slow blood allows clotting to be triggered easil

Question 26

primary haemostatis disorder

Answer 26

bleeding disorder | platelet plug formation isnt working very well

Question 27

medical name for a bruise

Answer 27

haematoma

Question 28

what is a haemoatoma

Answer 28

micro or macroscopic tearing of the blood vessels | the leaked blood cells are phagocytosed ad degraded over time

Question 29

blue/red bruise

Answer 29

haemoglobin

Question 30

green bruise

Answer 30

biliverdin

Question 31

yellow brise

Answer 31

billirubin

Question 32

golden bruise

Answer 32

hemosiderin

Question 33

3 types of bruise

Answer 33

petichiae purpura echymoses

Question 34

causes of bleeding defects

Answer 34

vascular defects low plalet numbers disorders of platelet function coagulation

Question 35

low platlet numbers

Answer 35

thrombocytopenia

Question 36

example of coagulation disorder

Answer 36

``` heamophilia results in: - delayed bleeding intramuscualr haemotmas more males ```

Question 37

exaxmples of primary haemostastic disorders

Answer 37

thrombocytopenia VWD - petichae, nose bleeds

Question 38

nose bleeds

Answer 38

epistaxes

Question 39

signs of a thrombotic disorder

Answer 39

coronary arties: chest pain carotis arteires: stoke deep veins of legs: unilateral leg pain

Question 40

risk factors for haemostastic disorders

Answer 40

``` age gender ethnic asprin use warfarin use previous thrombosis ```

Question 41

examples of heamostastic investigations

Answer 41

``` Full blood count (purple vacutainer – EDTA) Blood film or smear (morphology) Bleeding time: normal = 3-8min PFA-100 (replaced bleeding time) Platelet aggregation studies Flow cytometry Serum thromboxane Aspirinworks (urine test for thromboxane) Coagulation Assays (blue vacutainer – citrate) Prothrombin time (INR) Activated partial thromboplastin time Thrombin Time Factor Assays PCR D-dimer Assays ```

Question 42

examples of easy bleeding

Answer 42

``` epitaxis blood in stools gum bleding musocal lining bleedings heavy periods ```

Question 43

what vacutainer is usedd for a full blood count

Answer 43

purple one | contains EDTA

Question 44

what is EDTA

Answer 44

anticoag powder form so doesnt dilute the blood binds calcium to stop cogaultion permanent

Question 45

cagulation assay vacutainer

Answer 45

blue sodium citrate liquid form mops up calcium temportatiliy preventing coagulation

Question 46

prothrombin time

Answer 46

INR

Question 47

examples of coagulation assasy

Answer 47

prthombin tme activated partia thromboplastin time thrombin time

Question 48

blood film

Answer 48

used to asses the blood cells down the micoscope

Question 49

PFA

Answer 49

platelet function analyser machine moves blood through capillary tube with collagen in and measure the time it takes for the tube to eet blocked measures accurately the platelet fuunction

Question 50

platelet aggregation studies

Answer 50

puify platlers and shine light through if they are active adn stuck together, lots of light through inaccive, not much through not used in hopsitals through ay more

Question 51

flow cytometry

Answer 51

flurestcent Ab to makr thigsn and make them seen

Question 52

serum thromboxane/aprinworks

Answer 52

looks at effect of asprin on blood | test used prior to surgery to check if patient has been using it as it might affect their abilty to clot

Question 53

efffect of low dose asprin

Answer 53

keeps platlers quiet in patienets at risk of arterial thrombosis

Question 54

what part of the coagulation pathway does prothombin time measure?

Answer 54

extrinsic pathway

Question 55

prothombin time in patientes on warfarin

Answer 55

longer | warfarin inhibits vit K being cycles and this is needed to make clotting factos so wihout it blood less likely to clot

Question 56

what part of the cogaultion cascad does the activated partial thromboplastin time measure

Answer 56

intrinsic pathway`

Question 57

what part of the coagultion assay does thrombin time measure

Answer 57

common pathway

Question 58

heparin

Answer 58

inhibits thrombin

Question 59

factor assays

Answer 59

testing for deficiencies | take plasma and add in normal plasma dnt he prolonged clotting time should be fixes showing a factor issue

Question 60

inhibition assay

Answer 60

used to asses too much of an inhibitiro | add patients plasma to normal plasma and the clotting time will be longer as stuff it being blocked

Question 61

D-dimer assay

Answer 61

these aremade from the breakdown of fibrin | clots mean more D-Dimers