Hemostasis

Question 0

Secondary hemostasis facts

Answer 0

Exposure of tissue factor and collagen at injury site

Activation of coagulation cascade by combination of factor VII with tissue factor

Stepwise activation of a series of pro-enzymes leading to thrombin production

Thrombin is recruits more platelets and clotting factors leading to more thrombin production

Thrombin also convert soluble fibrinogen to fibrin

Cross linking of fibrin clot by factor XIII

Question 1

During primary hemostasis

Recruitment of platelets happens by:

What is formed

Answer 1

Adhesion, activation and aggregation

This forms an occlusive plug

Question 2

Formation of platelet fribrin plug is mediated by

Answer 2

Platelet vessel interaction

The coagulation system

Question 3

Why no clotting with intact endothelium?

Answer 3

Does not interact with clotting factors

Question 4

Ehlers danlos syndrome

Answer 4

Defect in ECM

• defect in synthesis of collagen
• 6 types (classical skin, hyper mobility , vascular )

Autosomal dominant or recessive

Proteins COL A1-A5

Question 5

What are the adhesive proteins

What happen if any one is defective?

Answer 5

Collagen, elastin, von willebrand fActor

Hard for platelets to adhere (also leukocytes)

Question 6

Extrinsic pathway

What is the test for it

Answer 6

Tissue factor was exposed

• factor 7 activated and starts a whole process

Test is prothrombin time or PT
- measures all vit k dependent factors (2.7.9 and 10). But major one is factor 7

Question 7

Intrinsic pathway

What test is used

Answer 7

Factors 12, 11, 9 and 8 come into action

Particular factor 8
- interacts well with Von willebrand factor

Test is activating partial thromboplastin time (APTT). 9,11,8 and 12 . Particularly 8 and 9. Abnormality can lead to abnormality and clotting disorder.

Question 8

Pts with Von will disease also have low

Answer 8

Factor 8

Question 9

Deficiency of any factor does what

Answer 9

Does not allow coagulation to occur at normal rate

Question 10

Fibrin cross linking is done by what factor

Answer 10

13

Question 11

Factor 10

Answer 11

Factor 10 is activated by both pathways

Prothrombin to thrombin

Question 12

Most important factor is

Answer 12

factor 7

All others can be bypassed

Question 13

Diseases of coagulation (common)

Answer 13

Von will

Hemophilia (a,b,c)

Factor 7 deficiency

Question 14

Regulation

Answer 14

Anti-thrombins (AT-III).

Tissue pathway inhibitor (TFPI)

Protein c and protein a system

Question 15

Fibrolytic system

Answer 15

Lyse of clot

-plasmin most important agent

Protein inhibitors regulate this
- PAI -1 PAI -2, alpha 2 anti-plasmin, alpha 2 macroglobulin

Question 16

Virchows triad

Answer 16

Injury to endothelium

Alterations in normal bloodflow

Alterations in blood- hypercoagulability

Question 17

Hypercoagulability

Answer 17

The family had it

Inherited
- prot c and prot s deficiency

Acquired
- anti-phospholipid antibodies