1 - Hemostasis and Coagulation Flashcards
Timing of Hemostasis:
Vasoconstriction (immediately)
Platelet adhesion
Platelet aggregation
Primary Hemostasis
Timing of Hemostasis:
Activation of clotting factors
Fibrin formation
Secondary hemostasis
Timing of Hemostasis:
Activation of fibrinolytic factors
Clot lysis
Fibrinolysis
Key players of Primary Hemostasis
Platelet
Blood vessels
Endpoint of primary hemostasis
Platelet plug
Key players of secondary hemostasis
Coagulation system
Enzymes
Cofactors
Platelets
End product of Secondary hemostasis
Stabilized fibrin clot
Key players of fibrinolysis
Fibrinolytic system
End product of fibrinolysis
Dissolution of fibrin clot (Healing)
Anticoagulant properties of Intact Vascular Intime
- Prostacyclin
- Nitric oxide
- Tissue Factor Pathway Inhibitor
- Thrombomodulin
- Heparan sulfate
providing a smooth inner surface of the blood vessel that prevents harmful turbulence that otherwise may activate platelets and coagulation enzymes
Rhomboid and contiguous ECs
separating procoagulant proteins and platelets in blood from collagen & tissue factor in fibroblasts and smooth muscle cells
ECs as a physical barrier
Platelet inhibitor and a vasodilator
Prostacyclin
induces smooth muscle relaxation and subsequent vasodilation, inhibits platelet activation, and promotes angiogenesis
Nitric oxide
Eicosanoid platelet inhibitor
Prostacyclin
vascular “relaxing” factor
nitric oxide
coagulation extrinsic pathway regulator
tissue factor pathway inhibitor
a protein C coagulation control system activator
thrombomodulin
Procoagulant properties of Damage Vascular Intima:
- Vasoconstriction
- Collagen
- von Willebrand factor
- ADAMTS-13
- P-selectin
- Intercellular adhesion molecules (ICAMs)
- Platelet endothelial cell adhesion molecules (PECAMs)
- Smooth muscle cells and fibroblasts
- Tissue factor
necessary for platelet adhesion to collagen
von Willebrand factor
promotes platelet leukocyte binding
P-selectin
ICAMs (Intercellular adhesion molecules)
PECAMs (Platelet endothelial cell adhesion molecules)
3 fibrinolytic properties:
- Tissue plasminogen activator (TPA)
- Plasminogen activator inhibitor-1 (PAI-1)
- Thrombin-activatable Fibrinolysis Inhibitor (TAFI)
A serine protease, activates fibrinolysis by converting plasminogen to plasmin
Tissue plasminogen activator (TPA)
TPA control protein that inhibits plasmin generation and fibrinolysis
Plasminogen activator inhibitor-1 (PAI-1)
Thrombin-thrombomodulin complex
Thrombin-activatable Fibrinolysis Inhibitor (TAFI)
Activated by thrombin bound to EC membrane thrombomodulin
Thrombin-activatable Fibrinolysis Inhibitor (TAFI)
Platelets are produced from the cytoplasm of bone marrow
megakaryocytes
Platelets function:
Plts roll and cling to non-plt surfaces, reversible
Adhesion
Give clinical significance for Adhesion
Bernard-Soulier Syndrome
von Willebrand disease
Platelets function:
Plts adhere to each other; irreversible
Aggregation
Give clinical significance for Aggregation
Glanzmann thrombasthenia
Afibrinogenemia
Platelets function:
Plts discharge the contents of their granules; irreversible
Secretion
Platelet granule:
B-Thromboglobulin
a-granules
Platelet granule:
Adenosine diphosphate
dense granules
Platelet granule:
Factor V
a-granules
Platelet granule:
Adenosine triphosphate
dense granules
Platelet granule:
protein s
a-granules
Platelet granule:
calcium
dense granules
Platelet granule:
fibrinogen
a-granules
Platelet granule:
serotonin
dense granules
Platelet granule:
VWF
a-granules
Platelet granule:
platelet factor 4
a-granules
Platelet granule:
platelet-derived growth factor
a-granules
procoagulant enzymes that are in inactive form
zymogens
bind, stabilize, and enhance the activity of enzyme
cofactors
examples of zymogens
Factor 7, 9, 10, 11, 12, 13
Prekallikrein
Prothrombin
examples of cofactors
Factor V, VIII
Protein Z
HMWK
Tissue factor
Protein S
Thrombomodulin
Factor I
Fibrinogen
Plasma coagulants:
Thrombin substrate, polymerizes to form fibrin
Factor I - Fibrinogen
Factor II
Prothrombin
Factor III
Tissue factor
Factor IV
Ionic calcium
Factor V
Proaccelerin
Plasma coagulants:
Stable factor, Serum prothrombin conversion accelerator, Autoprothrombin I, Cothromboplastin
Factor VII - Proconvertin
Factor VIII
Antihemophilic factor
Factor IX
Christmas factor
Factor X
Stuart-Prower factor
Factor XI
Plasma Thromboplastin Antecedent (PTA)
Factor XII
Hageman factor
Prekallikrein
Fletcher factor, pre-K
High molecular weight kininogen
Fitzgerald factor, HMWK
Factor XIII
Fibrin-stabilizing factor (FSF)
example of control proteins
- Antithrombin
- Heparin cofactor II
- TFPI
- Protein C
- a2-macroglobulin
- a1- antitrypsin
- ZPI
Vitamin K is a quinone found in green leafy vegetables and is produced by the intestinal organisms
Bacteriodes fragilis
Escherichia coli
3 Groups of coagulation factors
- Thrombin sensitive group (Factors I, V, VIII, XII)
- Vitamin K dependent group (Factors II, VII, IX, X, PROTEIN C, S, and Z)
- Contact group (Factors XI, XII, pre-K, HMWK)
Receptor dor FVIIa
Tissue factor
Activated by thrombin and inactivated by protein C
Factors V and VIII
cofactor to XIIIa and prekallikrein
HMWK
coagulation control cofactors
- Thrombomodulin
- Protein S
- Protein Z
Thrombin cofactor, fibrinolysis; when bound to thrombin activates protein C and TAFI
Thrombomodulin
Cofactor to protein C
Protein S
Two phases of Coagulation:
- Initiation
- Propagation
Two phases of Coagulation:
Occurs on tissue-factor bearing cells
Initiation
Two phases of Coagulation:
Occurring on platelets
Propagation
Principal regulators of Coagulation
- Tissue factor pathway inhibitor (TFPI)
- Activated protein C (APC)
- Antithrombin (AT)
The final stage of hemostatic activation
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)
Or soft tissue hemorrhage - a generalized bleeding that is seen in acquired or congenital defects in secondary hemostasis
Anatomic hemorrhage
Pattern of inheritance in which the transmission of a dominant allele on an autosome causes a trait to be expressed in heterozygotesv
Autosomal dominant
Pattern of inheritance resulting from the transmission of a recessive allele that is not expressed in heterozygotes
Autosomal recessive
Hemorrhagic spot, 1 cm or larger in dm, typically forming an irregular blue or purplish patch.
Ecchymoses
Nosebleed that requires intervention
Epistaxis
Bleeding from multiple sites, spontaneous and recurring bleeds, or hemorrhage that requires physical intervention of transfusion
Generalized hemorrhage
Chronic joint bleeds that cause inflammation and immobilization
Hemarthroses
Vomiting of bright red blood
Hematemesis
Localized collection of extravasated blood, usually clotted, in an organ space or tissue
Hematoma
Intact RBCs in the urine
Hematuria
Free hemoglobin in the urine
Hemoglobinuria
Expectoration of blood secondary to hemorrhage in the larynx, trachea, bronchi and lungs
Hemoptysis
Passage of fresh, red blood in your stool
Hematochezia
Stool containing dark red or black blood
Melena
Abnormally heavy or prolonged menstrual periods
Menorrhagia
Pinpoint purple or red spots on the skin or mucous membranes, approx 1 mm in dm
Petechiae
Purple skin discoloration, typically rounded with a dm of greater than 3 mm
purpura