HAEMOSTASIS

Question 1

what is haemostasis

Answer 1

arrest of bleeding and maintenance of vascular patency

Question 2

what is primary haemostasis

Answer 2

formation of a platelet plug

Question 3

what is secondary haemostasis

Answer 3

formation of a fibrin clot

Question 4

what 2 mechanisms moderate the haemostatic system

Answer 4

fibrinolysis and anticoagulation

Question 5

how are platelets formed

Answer 5

budding off from megakaryocytes

Question 6

what are platelets made of

Answer 6

negatively charged phospholipids

Ca2+ ions

Question 7

do platelets have a nucleus

Answer 7

no - they are buds of cytoplasm rather than true cells

Question 8

what is the lifespan of a platelet

Answer 8

7-10 days

Question 9

give an example of an antiplatelet drug

Answer 9

aspirin

Question 10

endothelial (vessel wall) damage exposes ____ and releases ____

Answer 10

collagen

VWF

Question 11

how do platelets bind to VWF

Answer 11

they possess receptors

glycoprotein 1B

Question 12

what happens following the initial binding of platelets to VWF

Answer 12

activation of platelets which involves a change of shape

Question 13

release of ___ and ____ stimulates platelet aggregation and adhesion to form plug

Answer 13

ADP

thromboxane A2

Question 14

how do platelets bind to eachother

Answer 14

glycoprotein 2B3A

Question 15

give 3 causes of failure of platelet plug formation

Answer 15

vascular
platelet - reduced number or function
VWF - low or absent

Question 16

what is the name for reduced platelets

Answer 16

thrombocytopenia

Question 17

what are some s/s of platelet plug formation failure

Answer 17

bruising
purpura
mucosal bleeding - epistaxis, GI, conjunctival, menorrhagia
ICH

Question 18

what should you look for in the eyes of someone with a suspected bleeding disorder

Answer 18

conjunctival / retinal haemorrhages

Question 19

how can failed primary haemostasis be screened

Answer 19

platelet count

Question 20

why do elderly patients bleed more easily

Answer 20

less collagen so less efficient haemostasis

Question 21

what organ produces all the clotting factors involved in secondary haemostasis

Answer 21

liver

Question 22

what are the vitamin K dependent factors

Answer 22

2 7 9 10

Question 23

how do clotting factors bind to platelets

Answer 23

bind to Ca2+ ions

Question 24

what factors are involved in the initiation of the fibrin clot

Answer 24

tissue factor - factor VIIa

Question 25

what factors are involved in the propagation of the fibrin clot

Answer 25

factor VIII - IXa

Question 26

describe the intrinsic pathway of clotting

Answer 26

``` 12 - 12a II - IIa 9 - 9a 9a:8a 10 - 10a 10a:5a prothrombin - thrombin ```

Question 27

what clotting factor is prothrombin

Answer 27

2 (II)

Question 28

what clotting factor is thrombin

Answer 28

2a (IIa)

Question 29

describe the extrinsic pathway of clotting

Answer 29

endothelial trauma --> tissue factor : factor 7a 10 - 10a 10a:5a prothrombin - thrombin

Question 30

what pathway initiates clotting

Answer 30

extrinsic

Question 31

what pathway propagates clotting

Answer 31

intrinsic

Question 32

what causes fibrinogen --> fibrin

Answer 32

thrombin

Question 33

give the name of a serine protease that blocks all pathways of the cascade

Answer 33

anti-thrombin III

Question 34

what factor is involved in the stabilising of the fibrin clot

Answer 34

XIIIa (13)

Question 35

what switches on protein C and S

Answer 35

thrombomodulin

Question 36

active protein C negatively acts on what factors

Answer 36

5 (V) | 8 (VIII)

Question 37

_____ amplifies the clotting cascade

Answer 37

thrombin

Question 38

_____ uses thrombomodulin to switch roles and inhibit coagulation

Answer 38

thrombin

Question 39

activated ____ has a negative feedback control

Answer 39

fibrin

Question 40

what breaks down fibrin

Answer 40

plasmin

Question 41

where are protein S and C found

Answer 41

surface of platelets

Question 42

what inhibits factor VII - VIIa

Answer 42

tissue factor pathway inhibitor

Question 43

what would cause failure of fibrin clot formation (3)

Answer 43

single clotting factor deficiency multiple clotting factor deficiency increased fibrinolysis

Question 44

what activates plasminogen --> plasmin

Answer 44

tissue plasminogen activator (tPA)

Question 45

what is something that fibrin is broken down to

Answer 45

D-dimer

Question 46

what is an example of a single clotting factor deficiency

Answer 46

haemophilia

Question 47

what factor is deficient in haemophilia a

Answer 47

factor VIII (8)

Question 48

what factor is deficient in haemophilia b

Answer 48

factor IX (9)

Question 49

what is DIC

Answer 49

disseminated intravascular coagulation - widespread clotting which depletes the clotting factors and platelets leading to widespread bleeding

Question 50

what is fibrinolysis

Answer 50

clot breakdown

Question 51

what is used to screen for fibrin clot formation problems

Answer 51

prothrombin time | activated partial thromboplastic time

Question 52

with bleeding disorders you can get bleeding into ___ and ____

Answer 52

joints and muscles

Question 53

what is thrombophilia

Answer 53

deficiency of naturally occurring anticoagulants

Question 54

what are you increased likelihood of getting with thrombophilia

Answer 54

venous thrombosis

Question 55

what are some examples of naturally occurring anticoagulants

Answer 55

serine protease inhibitors - antithrombin III | protein S and C

Question 56

what measures the common pathway

Answer 56

thrombin time

Question 57

what measures the extrinsic pathway

Answer 57

prothrombin time

Question 58

what measures the intrinsic pathway

Answer 58

APPT

Question 59

what vitamin is required to form collagen

Answer 59

vitamin C

Question 60

why are purpuric rashes more common on lower limbs

Answer 60

oncotic pressure due to gravity pushes fluid (+blood) out of capillaries

Question 61

megakaryocytes are derived from the same lineage as ___

Answer 61

RBCs

Question 62

what measurement is good for warfarin monitoring

Answer 62

prothrombin time (factor VII)

Question 63

what measurement is good for heparin monitoring

Answer 63

APTT (factor VIII/IXa)

Question 64

what is the most common type of inherited thrombophilia

Answer 64

factor V leiden

Question 65

heparin inhibits the activation of what factors

Answer 65

2 9 10 11

Question 66

the activation of factor _ is where the extrinsic and intrinsic pathways meet

Answer 66

10

Question 67

_____ inhibits ADP - platelet activator

Answer 67

ADPase

Question 68

____ keeps the blood soluble and prevents platelet activation in normal conditions

Answer 68

prostacyclin