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hematology > Heme 2.5 > Flashcards

Flashcards in Heme 2.5 Deck (30)
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1
Q

how is any local bleeding “arrested”

A

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

2
Q

what is hemostasis desiged to ensure

A

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

3
Q

what is thrombosis

A

clots forming to easily

4
Q

how many platelets can a single megakaryocite produce

A

around 3000

5
Q

what amount of platelets are pooled in the spleen

A

about 20-30%

6
Q

what is the average lifespan of a platelet

A

5-20 days

7
Q

what artery layer is important for hemostasis

A

connective tissue layer (within the tunica intima)

8
Q

what triggers vasoconstriction in arteries and vains

A

the direct injury itself

sympathetic nervous system

9
Q

descrive platelet plug formation

A
  • 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
10
Q

how do platelets tick to exposed collagen of damaged endothelium

A

GPIa receptors (GP=glycoproten)

11
Q

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

A

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

12
Q

what happens to platelets when they adhere

A

the will indergo major structural changes and deformities

13
Q

what three things are stored within platelet granules

A

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

14
Q

what does fibrinogen bind to to link platelets together

A

GPIIb/IIIa

15
Q

what is the process of the cuagulation phase

A
  • 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
16
Q

what are most clotting factors existing as

A

zymogens (inactive form in the blood)

17
Q

clotting factor I (name and location

A

fibrinogen, liver

18
Q

CF II

A

prothrombin, liver

19
Q

CF III

A

tissue factro or thromboplastin, perivascular tissue

20
Q

CF IV

A

calcium, Plasma

21
Q

what are the vitamin K dependant CF

A

II, VII, IX, X

22
Q

CF V

A

proaccerlerin, LIVER

23
Q

CF VII

A

proconvertin (stable factor), liver

24
Q

what is the blood clotting cascade

A

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

25
Q

intrinsic pathway

A

initiated within the blood

26
Q

extrinsic pathway

A

initiated outside the blood

27
Q

what does the common pathway begin

A

when factor X is initiated

28
Q

what are three “natural” anti-coagulants

A
  • thrombomodulin
  • antithrombin III (or just antithrombin)
  • Heparin cofactor II
29
Q

what is inside a true clot

A

red cells, fibrin and proteins

30
Q

Where can Von Willebrands factor be found

A

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