UNIT 5 - PART 2 THROMBOCYTES AND HEMOSTASIS

Question 1

LIFE SPAN OF THROMBOCYTES IN BLOOD + SPLEEN?

Answer 1

Life span 5-9 days in blood + 36 hours stored in spleen.

Question 2

composition of thrombocyte= 4

Answer 2

1. no nucleus
2. dense granules = serotonin, atp, ca
3. alpha granuels (secretory organelles containing many proteins)
4. actin myosin filaments = transport

Question 3

what is throbopoiesis regulated by?

Answer 3

THROMOPOIETIN

Question 4

what are 3 phases of HEMOSTASIS? (CLOTTING)

Answer 4

1. vascular spasm= Release of serotonin and TXA2 ( clotting factors)
2. Primary hemostasis: platelet plug formation
3. Secondary hemostasis: coagulation
4. FIBRINOLYSIS

Question 5

what happens in PRIMARY HEMOSTASIS?

Answer 5

1. platlets bind to exposed collagen via adhesion protiens GP
2. platlet activating factors released = serotonin, adp, TXA2
3. platelet plug formation via platlets releasing chemicals of ‘stickness’ to neighbours

Question 6

what happens in SECONDARY HEMOSTASIS?

Answer 6

fibrin forms mesh traps RBCS + thrombocytes - CLOT

Question 7

what does oncotic pressure due to the BV’S?

Answer 7

pressure in BVS higher than outside due to the plasma proteins

Question 8

Platelet activation further constricted due to release of what?

Answer 8

release of ADP, thromboxane and serotonin

Question 9

what are Integrins?

Answer 9

=membrane proteins which increase their affinity for collagen when platelets are activated.

Question 10

aspirin inhibits COX = no PG2 which means >

Answer 10

less mucous = can feel burning

-inc risk in bleeding due to blockage of thrombaxne

Question 11

what is coagulation

Answer 11

enzymatic reactions where each clotting factor activates the following one, culminating in the formation of fibrin threads

Question 12

SECONDARY HEMOSTASIS COAGULATION DIVIDED IN 3 PHASES.

Answer 12

1st: Prothrombinase formation (extrinsic / intrinsic pathway)

• 2nd: Prothrombinase> prothrombin into thrombin
• 3rd: Thrombin> fibrinogen into> fibrin.

Fibrin forms the clot thread

Question 13

Most of the coagulation factors are synthesized in the liver and require what?

Answer 13

require vitamin K.

Question 14

which Is the most common coagulation disorders?

Answer 14

hemophilia A, due to the lack of factor VIII 8

Question 15

what is a thrombosis?

when does it become a EMBOLUS?

Answer 15

• appareace of clot in lumen, destroyed by fibrinolysis,

- if dislodged > bloodstream = EMBOLUS

Question 16

what does heparin do?

Answer 16

enhances antithrombin III action (ANTICOAG)

-which inhibits thrombin action

Question 17

what is von Willebrand disease ?

Answer 17

deficiency of von Willebrand factor= nose bleeding to internal bleeding)

Question 18

what does plasmin do?

Answer 18

Plasmin digests fibrin = no clot

+ inactivates fibrinogen (clotting factor)

Question 19

what does the ANTICOAG DRUG COUMARIN DO?

Answer 19

Antagonist to vitamin K

Question 20

what is a FIBRINOLYTIC DRUG?

Answer 20

(tPA)