Exam 3 Hemostasis & Coags Flashcards
The blood vessel endothelial layer contains?
- vWF
- tissue factor
- prostacyclin
- NO
The blood vessel media layer contains?
Collagen & Fibronectin
Endothelial cells synthesize & secrete (5)?
- Procoaculants
- anticoagulants
- fibrinolytics
- vasodilators
- vasoconstrictors
What is the purpose of vWF?
Help platelets adhere to subendothelial layer
What is the purpose of tissue factor?
Activate the clotting cascade
What mediators control blood flow by vasoconstriction?
- TXA-2
- adenosine diphosphate (ADP)
- Serotonin
What mediators control blood flow by vasodilation?
NO, prostacyclin
What are the 5 procoagulants?
- (C)ollagen
- (C)oagulation factors
- (F)ibronectin
- (T)hrombomodulin
- (v)WF
What is the function of Collagen?
Tensile strength of the plug
What is the function of Fibronectin?
- Mediates cell adhesion/anchoring fibrin
- (Fibronectin is the “Hitch” of fibrins)
What is the function of Thrombomodulin?
Regulates anticoagulation pathway
What is the function of Antithrombin III?
Degrades factors II, IX, X, XI, & XII
(2 & 9-12)
What medication helps to keep fibronectin in place?
TXA
What vessel layer influences blood flow via contraction?
Adventitia
Delineate the Nitric Oxide pathway?
- NOS converted into NO by L-arginine.
- NO diffuses into muscle cell & stimulates SGC to convert GTP into cGMP -> causing relaxation.
Name the 3 prostanoids/eicosanoids?
Prostacyclin,
Leukotriene,
TXA
What are the 2 functions of prostacyclin?
Vasodilation & interferes with platelet formation & aggregation
What are the 4 phases of hemostasis & coagulation?
Vascular phase (vascular spasm).
Primary hemostasis (plug formation).
Secondary hemostasis (coagulation & formation of fibrin).
Fibrinolysis (Clot lysis)
What hormones are involved in the vascular phase & they do what?
- Endothelins.
- Stimulate smooth muscle contraction, endothelial- smooth muscle- & fibroblast cell division
What are the 3 phases of platelet formation?
- Adherence
- Activation
- Aggregation
Where are about 1/3 of platelets sequestered?
In the spleen
What & where are platelets cleared?
By macrophages in the (R)eticulo(e)ndothelial (s)ystem & spleen
What is all (7) contained inside of platelets per lecture?
- (F)ibrin-stabilizing factor,
- (A)ctin & myosin,
- (C)alcium,
- (T)hrombosthenin,
- (s)erotonin,
- ADP,
- growth factor
What is present on platelet’s external surface?
Glycoproteins & phospholipids
What is the function of platelet’s glycoproteins?
Adhere to endothelium, collagen & fibrinogen.
GpIIb-IIIa complex links activated Plt together.
GpIb sticks Plt to vWF.
What happens during adherence?
vWF emerges from endothelial cell.
GpIb emerge from Plt surface.
GpIb attach to vWF
What happens during the Activation phase?
Plt conformational change –> swells, oval & irregular.
GpIIb & IIIa project outward from Plt’s surface & link to other platelets.
What happens during the Aggregation phase?
- Plt release mediators (alpha & dense granules, contractile granules, thrombin, etc).
- Mediators for primary unstable clot.
- Primary plug maintains hemostasis or clotting cascade is activated if injury is large.
What clotting factors are required for Fibrin production?
All of them
Which clotting factors are vitamin K dependent?
II, VII, IX & X
Which clotting factors are not made in the liver?
III, IV, VIII
What pathway will not work very well with a calcium deficiency?
Extrinsic pathway
What factors initiate the extrinsic pathway?
III & VII (37 cents buy the extrinsic pathway)
Delineate the extrinsic pathway?
- Tissue factor III activates pathway –> III activates factor VII to VIIa,
- VIIa w/ calcium (factor IV) activates factor X to Xa.
- Xa activates Prothrombin activator to convert Prothrombin to Thrombin (factor II).
- Factor V accelerates positive feedback & increases prothrombin activator production.
The extrinsic pathway needs___ to form a clot & the intrinsic pathway needs ___ to form a clot?
12-15sec & 6mins
What sets off the intrinsic pathway?
Blood trauma / exposure to collagen (factor XII)
Delineate the intrinsic pathway?
-Collagen exposure activates factor XII to XIIa conversion.
- XIIa activates XI to XIa.
- Factor XIa activates factor IX to IXa conversion.
- IXa & VIII activate factor X to Xa.
- Factor Xa activates prothrombin activator.
What factor is missing with hemophilia A?
Factor VIII
Delineate the common pathway?
- Prothrombin activator changes Prothrombin (II) to Thrombin (IIa).
- IIa changes Fibrinogen (I) to Fibrin
- Prothombin (II) activates XIIIa (Activated fibrin-stabilizing factor ) .
What prevents excessive fibrin deposition?
Fibrinolysis
Urokinase is produced & released where?
By the kidneys to prevent small clots getting lodged in the kidney tissue
What are 2 fibrinogenic factors?
(K)allikrien & (N)eutrophil (e)lastase
What is the function of Kallikrien & neutrophil elastase?
Convert plasminogen to plasmin
How does tPA work?
- Converts Plasminogen to Plasmin –>
- Breaks down Fibrin into Fibrin degradation split products
What are the values for BT, PT, aPTT, TT, ACT & Fibrinogen?
BT= 3-10mins
PT= 12-14sec
aPTT= 25-35sec
TT= 30sec
ACT= 80-150sec
Fibrinogen= >150 mg/dL
