Haemostasis

Question 1

define haemostasis

Answer 1

the arrest of bleeding AND

the maintenance of vascular patency

Question 2

what is formed in primary haemostasis?

Answer 2

a platelet plug

Question 3

what is formed in secondary haemostasis?

Answer 3

fibrin clot

Question 4

is a platelet plug or fibrin clot more secure?

Answer 4

fibrin clot

Question 5

what happens to stop formation of the fibrin clot?

Answer 5

fibrinolysis

Question 6

name the 4 stages of haemostasis

Answer 6

primary
secondary
fibrinolysis
anticoagulant defences

Question 7

biggest cell in the bone marrow?

Answer 7

megakaryocyte

Question 8

describe the relationship between platelets and megakaryocytes

Answer 8

formed in the cytoplasm of megakaryocytes and “bud” off

Question 9

when should you stop aspirin before surgery? why?

Answer 9

7 -10 days before

this is the mean life span of platelets

Question 10

when endothelial cells are damaged what attracts the platelets to adhere to them?

Answer 10

collagen

von willebrand factor

Question 11

what happens to platelets after they adhere to damaged endothelial cells?

Answer 11

release chemicals that cause them to aggregate (stick together)

Question 12

causes of failure of the platelet plug?

Answer 12

vascular
reduced function/number of platelets
VWF deficiency

Question 13

what vitamin is responsible for making collagen? what effect does this have on clotting and why?

Answer 13

C

no collagen = no signal for platelets to adhere to the wall

Question 14

what happens in ITP (immune thrombocytopaenic purpura)?

Answer 14

antibodies stick to platelets and cause them to be removed -> thrombocytopaenia

Question 15

commonest inherited bleeding disorder?

Answer 15

VWF deficiency

Question 16

VWF affects __% of the popn

Answer 16

1%

Question 17

signs of failure of the platelet plug in patients

Answer 17

lower limb purpura (gravity pushes platelets down = more leaking)!!
blood blisters in mouth
epistaxis
GI bleed
conjunctival haemorrhage
menorrhagia
intracranial haemorrhage if severe

Question 18

Ix primary haemostatic problems

Answer 18

platelet count

Question 19

phospholipids tend to be __vely charged

Answer 19

negatively

Question 20

what forms the surface of the platelet plug and why?

Answer 20

calcium

the neg charged phospholipids within the platelet attract positively charged Ca

Question 21

what does the “a” mean on a clotting factor?

Answer 21

activated form

Question 22

what is released from damaged endothelium?

Answer 22

tissue factor

Question 23

what is the first clotting factor to respond to tissue factor?

Answer 23

factor 7

Question 24

factor _ and _ form prothrombin

Answer 24

5 and 10

Question 25

what clotting factors are needed to form factor 5 and 10

Answer 25

TF factor 7 VIII IXa

Question 26

haemophilia A is a deficiency of what CF?

Answer 26

8

Question 27

haemophilia B is a deifciency of what CF?

Answer 27

9

Question 28

clotting factors are made..

Answer 28

in liver

Question 29

causes of failure of fibrin clot formation?

Answer 29

single CF deficiency multiple CF deficiency increased fibrinolysis

Question 30

give an example of a multiple CF deficiency

Answer 30

DIC

Question 31

what enzyme breaks fibrin down?

Answer 31

plasmin

Question 32

plasmin is formed from..

Answer 32

plasminogen

Question 33

Hx questions in bleeding disorders?

Answer 33

``` bleeding/bruising duration previous surgery/dental extraction menstrual history DH FH ```

Question 34

prothrombin time measures what CF formation?

Answer 34

TF | VIIa

Question 35

activated partial thromboplastin time measures what CF formation?

Answer 35

VIII | IXa

Question 36

name the 2 ways in which factor 10a can be formed

Answer 36

combine factor 8 and 9a | combination of tissue factor and factor 7

Question 37

what CFs are involved in the initiation phase

Answer 37

7 TF 10

Question 38

what CFs are involved in the amplification phase

Answer 38

5 8 9 10

Question 39

what activates factor 8 and 9

Answer 39

thrombin

Question 40

protein _ switches off CFs to stop haemostasis

Answer 40

protein c

Question 41

what does thrombin bind to when it senses haemostasis has been achieved and what effect does this have?

Answer 41

thrombomodulin | stops haemostasis

Question 42

name the deficiency in thrombophilia?

Answer 42

naturally occuring anticoagulants

Question 43

name the body's naturally occurring anticoagulants

Answer 43

protein C | serine protease inhibitors

Question 44

causes of thrombocytosis

Answer 44

bone marrow disease splenectomy inflammatory disease

Question 45

what cancers can present as thrombocytosis

Answer 45

``` LEGO-C lung endometrial gastric oesophageal colorectal ```