INTRODUCTION AND VASCULAR SYSTEM Flashcards
Process if there’s an injury:
- Primary Hemostasis
- Secondary Hemostasis
- Fibrinolysis
a complex physiologic process that keeps
circulating blood in a fluid state and then, when an injury occurs, produces a clot to stop the bleeding, confines the clot to the site of injury, and finally dissolves the clot as the wound heals
HEMOSTASIS
uncontrolled bleeding
Hemorrhage
pathologic clotting
Thrombosis
Cellular elements of hemostasis
- cells of the vascular intima
- extravascular tissue factor bearing cells
- platelets
Plasma components of hemostasis
Coagulation proteins
Fibrinolytic proteins
refers to the role of blood vessels and
platelets in the initial response to a
vascular injury or to the commonplace
desquamation of dying or damaged
endothelial cells
PRIMARY HEMOSTASIS
describes the activation of a series of
coagulation proteins in the plasma, mostly
serine proteases, to form a fibrin clot
Secondary Hemostasis
the final event of hemostasis, the gradual digestion and removal of fibrin
clot as healing occurs
Fibrinolysis
Activated by desquamation and small injury to the blood vessels
Primary hemostasis
Involves vascular intima and platelets
Primary Hemostasis
Rapid, short-lived response
Primary Hemostasis
Procoagulants substances exposed or released by damage or activated endothelial cells
Primary Hemostasis
The activator, tissue factor is exposed on the cell membrane
Secondary Hemostasis
Involves platelets and coagulation system
Secondary Hemostasis
Activated by large injuries to blood vessels and surrounding tissues
Secondary Hemostasis
Are complex and heterogeneous
Endothelial cells
Are distributed throughout the body. Display unique structural and functional characteristics
Endothelial cells
Play essential roles in immune response, vascular permeability, proliferation, and hemostasis. Form a smooth, unbroken surface that eases the fluid passage of
blood
Endothelial cells
Anticoagulant Properties of Vascular
Intima:
- Prostacyclin
- Nitric oxide
- Thrombomodulin
- Tissue Factor Pathway Inhibitor
- Heparan Sulfate
Procoagulant Properties of Vascular
Intima:
- Vasoconstriction
- Collagen
- Von Willebrand Factor
- ADAMST 13
- P-selectin
- Intracellular adhesion molecule
- Platelet endothelial cell adhesion molecules
- Smooth muscle cells and fibroblast
- Tissue factor
Fibrinolytic Properties of Vascular
Intima:
Tissue Plasminogen Activator (TPA)
Plasminogen Activator Inhibitor-(PAI-1)
Thrombin Activatable Fibrinolysis Inhibitor
(TAFI)
Platelet size:
2-4 um
shape of the platelets
disk-shaped, biconvex/spiky
granular and located centrally
Chromomere
agranular and located in the periphery
Hyalomere
Primary Hemostasis steps:
- Platelet Adhesion
- Shape Change
- Secretion of granules (ADP, TXA2)
- Recruitment
- Platelet Aggregation
Platelet a-granules
1.b- thromboglobulin
2. FV
3. FXI
4. Protein S
5. Fibrinogen
6. VWF
7. Platelet factor 4
8. Platelet derived growth factor
Platelet Dense Granules
- ADP
- ATP
- Serotonin
- Calcium
- Magnesium
Plasma transports at least ____, also called coagulation
factors (synthesized in the liver)
16 procoagulant
Vitamin K is a quinone found in green leafy vegetables and is produced by the intestinal organisms _____
Bacteroides fragilis and
Escherichia coli
Two Phases of Coagulation
Initiation
Propagation
Occurs on tissue-factor bearing cells
Initiation
Occurring on platelets
Propagation
Secondary Hemostasis steps :
- Tissue Factor
- Phospholipid complex expression
- Thrombin activation
- Fibrin Polymerization
Ensures that coagulation is localized and is not a systemic response (prevents excessive clotting or thrombosis)
- Tissue Factor Pathway Inhibitor (TFPI)
- Activated Protein C (APC)
- Antithombin (AT)
The final stage of hemostatic activation. Is the systematic, accelerating hydrolysis of fibrin by plasmin
Fibrinolysis
binds to the lysine moieties on the fibrin molecule
Plasminogen
Active form of plasminogen
Plasmin
Plasminogen Activation
Tissue Plasminogen Activator (TPA)
Urokinase Plasminogen Activator (UPA)
Control of Fibrinolysis
Plasminogen Activator Inhibitor-1 (PAI-1)
Alpha 2- Antiplasmin
Thrombin Activatable Fibrinolysis
Inhibitor (TAFI)