Chapter 4: Hemostasis And Related Disorders Flashcards
Formation of weak platelet plug mediated between interaction btw platelets and endothelium
Primary Hemostasis
Strengthening of weak platelet plug via coagulation cascade
Secondary Hemostatsis
What are the 4 steps of Primary Hemostatsis
Transient vasoconstriction
Platelet Adhesion
Platelet degranulation
Platelet aggregation
What 2 processes mediate transient vasoconstriction
Neural Reflex
Release of ENDOTHELIN from damage cells
Before platelets can bind, what molecule must interact with exposed collagen on the damaged endothelium
vWF !
where if vWF produced in the body
Alpha granules of platelets
Weibel Palade Bodies of the endothelium
Once vWF is bound to exposed to collagen what receptor on platelets interacts with vWF ?
Gp1B
What other important adhesion molecule is made in the Weibel Palade bodies besides vWF ?
P-selectin (used in rolling of WBC)
Upon interation of vWF to Gp1b what occurs ?
Platelet Degranulation
What two products are released by platelet degranulation
ADP
TxA2
ADP causes the up regulation of which protein on platelets ?
GpIIB/IIIA receptor
TxA2 has what effect ?
Increases platelet aggregation
What enzyme makes TxA2 ?
COX (platelet)
What is the function of GpIIB/IIIA receptor ?
Platelet aggregation
What does GpIIB/IIIA receptor bind to ?
Fibrinogen (linker protein between two platelets)
Quantitative primary hemostasis disorder are due to …
NOT ENOUGH PLATELETS (Thrombocytopenia)
Qualitative primary hemostasis disorder are due to …
Defective Platelets
What are common symptoms of primary hemostasis disorders ?
SKIN BLEEDING Mucosal bleeding: Epistaxis GI bleeding Intracranial bleeding (Thrombocytopenia) Hemoptysis
Petechiae
1-2 mm lesions of skin bleeding
Purpura
3mm or greater lesions of skin bleeding
Ecchymoses
Greater than 1cm lesion of skin bleeding
Normal level of platelets
150-400 K/uL
Level at which symptoms of thrombocytopeina are notices
<50K/ uL
Normal bleeding time
2-7 minutes