WEEK 1- Introduction & The Vascular system Flashcards
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
Out of balance
Hemostasis
Overview of hemostasis
Vasoconstriction
Platelet adhesion and aggregation
Coagulation enzyme and activation
Cellular elements of hemostasis
Cells of vascular intima
Extravascular tissue factor (TF 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
Fibrinolysis
the gradual digestion and removal of fibrin
clot as healing occurs
Fibrinolysis
Activated by desquamation and small injuries to blood vessels
Primary hemostasis
Activated by large injuries to blood vessels and surrounding tissues
Secondary hemostasis
Involves vascular intima and platelets
Primary hemostasis
Rapid, short-lived response
Primary hemostasis
Procoagulant substances exposed or released by damaged or activated endothelial cells
Primary hemostasis
Activated by large injuries to blood vessels and surrounding tissues
Secondary hemostasis
Delayed, long-term response
Secondary hemostasis
The activator, tissue factor, is exposed on cell membranes
Secondary hemostasis
Are complex and heterogeneous and distributed throughout the body
Endothelial cells
Display unique structural and functional characteristics and play essential roles in immune response, vascular permeability, proliferation, and hemostasis
Endothelial cells
Form a smooth, unbroken surface that eases the fluid passage of blood
Endothelial cells
Innermost vascular lining
Endothelial cells (endothelium)
Supporting the endothelial cells
Internal elastic lamina composed of elastin and collagen
Subendothelial connective tissue
Collagen and fibroblasts in veins
Collagen, fibroblasts, and smooth muscle cells in arteries
Anticoagulant Properties of Vascular Intima
Prostacyclin
Nitric oxide
Tissue factor pathway inhibitor
Thrombomodulin
Heparan sulfate
Procoagulant Properties of Vascular Intima
Vasoconstriction
Collagen
Von Willebrand Factor (vWF)
ADAMTS-13
P-selectin
Intercellular adhesion molecules (ICAMs)
Platelet endothelial cell adhesion molecules (PECAMs)
Smooth muscle cells and fibroblasts
Tissue Factor
Fibrinolytic Properties of Vascular Intima
Tissue Plasminogen Activator (TPA)
Plasminogen Activator Inhibitor-1 (PAI-1)
Thrombin Activatable Fibrinolysis Inhibitor (TAFI)
Platelet Morphology size
2-4 um
Platelet Morphology shape
disk-shaped, biconvex/spiky
Plate morphology Cytoplasm
light blue to purple, presence of chromomere and hyalomere
Platelet morphology Chromomere
granular and located centrally
Platelet morphology hyalomere
agranular and located in the periphery
serves as the body’s first line of defense against blood loss
Platelets
Platelets roll and cling to non platelet surfaces
Adhesion
Plateleys adhere to each other
Aggregation
Platelets discharge the contents of their granules
Secretion
Reversible
Adhesion
Irreversible
Aggregation
Secretion
Seals endothelial gaps, some secretion of growth factors , in arterioles VWF is necessary for adhesion
Adhesion
Platelet plugs form, platelet contents are secreted, requires fibrinogen
Aggregation
Occurs during aggregation, platelet contents are secreted, essential to coagulation
Secretion
Platelet dense granules
Adenosine diphosphaye (activates neighboring platelets)
Adenosine triphosphate
Calcium
Serotonin ( vasoconstrictor)
Plasma transports at least 16 procoagulant, also called
Coagulation fctors
Coagulation factors are synthesized in
Liver
How many enzymes that circulate as zymogens
8