Flashcards in 08 Hemostasis Deck (33):
1
Process of blot clot formation at the site of vessel injury
Hemostasis
2
Average time of hemostasis
20 minutes
3
Phases of hemostasis
Primary
Secondary
Fibrinolysis
4
Initial step in stopping the bleeding after a blood vessel injury
Primary hemostasis
5
Fast-acting (~5 minutes)
Weak and not permanent
Interaction of platelet with blood vessel in which the end product is a platelet clot
Primary hemostasis
6
Activation of clotting factors
Secondary hemostasis
7
Causes fibrin to cluster
Involves RBCs and WBCs in creating a permanent clot
Around 10 minutes
Secondary hemostasis
8
Healing of the cut blood vessel and the blood clot dissolves after a few days
Fibrinolysis
9
Elements of hemostasis
Vascular walls
Endothelial cells
Platelets
10
Prevent loss in the blood vessel
Vascular walls
11
Negatively charged to repel circulating proteins and platelets
Produces and released substances that inhibit or promote platelets, coagulation and fibrinolysis
Ex: collagen, fibronectin
Endothelial cells
12
Produced from bone marrow
Contain granules that help in coagulation
Platelets
13
Maintain shape of platelets as discoid
Microtubules
Cytoskeleton
14
Actin filaments (responsible for change in shape of platelet) and glycoprotein 1B (adhesion)
Membrane skeleton
15
Plays a role in the activation of the cell and platelets surrounding activated platelets
Invagination of the plasma membrane that appears to be a tunnel
Surface connected open canalicular system
16
Highly specialized membrane
Remnant of smooth endoplasmic reticulum
Storage for calcium
Dense tubular system
17
Steps of primary hemostasis
Vasoconstriction
Platelet plug formation
18
Aka vascular spasm phase
Initial response to blood vessel endothelium injury
Vasoconstriction
19
Vasoconstriction is triggered by:
Direct injury to vascular smooth muscle
Chemicals released by endothelial cells
Platelets
Reflexes initiated by local pain receptors
20
Aka platelet phase
Platelets adhere to damaged endothelium
Regulated by thromboregulation
Temporary seals the break in the vessel wall
Platelet plug formation
21
Steps in platelet plug formation
Adhesion
Activation
Aggregation
22
Strong activating agent
Exposed collagen binds with vWF
Platelet adhesion
23
First adhesion site of platelet to damaged endothelium
Glycoprotein 1B
24
Large multimeric glycoprotein, circulates in the plasma and found in platelets
vWF
25
Release of alpha and dense granules
Release of thromoboxane A2
Enhance subsequent aggregation and increase surface area available for interaction with coagulation factors
Conformational change in platelet GPIIB/IIIA
Activation
26
Promoted by bridging interactions between fibrinogen and GPIIB/IIIA receptors on adjacent platelets
Platelet aggregation/hemostatic plug
27
Aka coagulation phase
Conversion of fibrinogen to fibrin
Rapid response reinforces the platelet plugs
Secondary hemostasis
28
Secondary hemostasis process
Initiation
Amplification
Propagation
29
Clot is removed following the healing of wound
Fibrinolysis
30
Absence of vWF hence no adhesion
von Willebrand deficiency
31
Deficiency in GP1B
No receptors attached to platelet
Bernard-Soulier syndrome
32
Deficiency in GPIIb-IIIa complex
No aggregation
Glanzmann thrombasthenia
33