Heme 2.5

Question 1

how is any local bleeding “arrested”

Answer 1

intereaction between platelets and blood vessel endothelial cells, fallowed by cascade of coagulation

Question 2

what is hemostasis desiged to ensure

Answer 2

there is no major leakage of blood following injury and consists of a complex system proteins and enzymes

Question 3

what is thrombosis

Answer 3

clots forming to easily

Question 4

how many platelets can a single megakaryocite produce

Answer 4

around 3000

Question 5

what amount of platelets are pooled in the spleen

Answer 5

about 20-30%

Question 6

what is the average lifespan of a platelet

Answer 6

5-20 days

Question 7

what artery layer is important for hemostasis

Answer 7

connective tissue layer (within the tunica intima)

Question 8

what triggers vasoconstriction in arteries and vains

Answer 8

the direct injury itself

sympathetic nervous system

Question 9

descrive platelet plug formation

Answer 9

• aggregation of platelets
• platelets stick to exposed collogen, swell, and form spiked process
• platelet plugs are effectin in preventing blood los due to small injuries

Question 10

how do platelets tick to exposed collagen of damaged endothelium

Answer 10

GPIa receptors (GP=glycoproten)

Question 11

what is von Willebrand’s Factor (vWF) and what receptor does is use

Answer 11

via GBIb receptors, it speciffically causes platelets to attach firmly to and spread across the damaged endothelial surface.

Question 12

what happens to platelets when they adhere

Answer 12

the will indergo major structural changes and deformities

Question 13

what three things are stored within platelet granules

Answer 13

ADP
Thromboxane (TA2; TXA2; a prostaglandin)
serotonin (5-HT)

Question 14

what does fibrinogen bind to to link platelets together

Answer 14

GPIIb/IIIa

Question 15

what is the process of the cuagulation phase

Answer 15

• occurs either to reinforce a platelet plug of to stop blead when a platelet plug fails
• involved numerous clotting factors which are often indicated by roman numerals
• most(not all) clotting cafros are proteins and are synthesized by the liver

Question 16

what are most clotting factors existing as

Answer 16

zymogens (inactive form in the blood)

Question 17

clotting factor I (name and location

Answer 17

fibrinogen, liver

Question 18

CF II

Answer 18

prothrombin, liver

Question 19

CF III

Answer 19

tissue factro or thromboplastin, perivascular tissue

Question 20

CF IV

Answer 20

calcium, Plasma

Question 21

what are the vitamin K dependant CF

Answer 21

II, VII, IX, X

Question 22

CF V

Answer 22

proaccerlerin, LIVER

Question 23

CF VII

Answer 23

proconvertin (stable factor), liver

Question 24

what is the blood clotting cascade

Answer 24

comprises intrinsic and extrinsic pathways- both are initiated mimultaneously and lead to final common pathway

Question 25

intrinsic pathway

Answer 25

initiated within the blood

Question 26

extrinsic pathway

Answer 26

initiated outside the blood

Question 27

what does the common pathway begin

Answer 27

when factor X is initiated

Question 28

what are three “natural” anti-coagulants

Answer 28

• thrombomodulin
• antithrombin III (or just antithrombin)
• Heparin cofactor II

Question 29

what is inside a true clot

Answer 29

red cells, fibrin and proteins

Question 30

Where can Von Willebrands factor be found

Answer 30

a protein found in plasma, platelets, and the walls of blood vessels