Pathoma Chapter 4 : Questions And Complete Answers
What do endothelial cells sit on top of? Right Ans - Basement membrane
Hemostasis Right Ans - Mechanism of repair of blood vessel wall that
involves formation of thrombus (clot) at the site of vessel injury
What are the two stages of hemostasis? Right Ans - Primary and secondary
hemostasis
Goal of primary hemostasis Right Ans - Formation of platelet plug
What two materials interact in primary hemostasis to form the platelet plug?
Right Ans - Platelets and the vessel wall
What is the goal of secondary hemostasis? Right Ans - Stabilize the platelet
plug
What mediates secondary hemostasis? Right Ans - Coagulation cascade
Name the four steps of primary hemostasis Right Ans - 1. Transient
vasoconstriction of damage vessel
2. Platelet adhesion to the surface of disrupted vessel
3. Platelet degranulation
4. Platelet aggregation
What two things mediated transient vasoconstriction in primary hemostasis?
Right Ans - 1. Neural reflex stimulation
2. Release of endothelin from enothelial cells
In platelet adhesion, how does vWF bind to the vessel? Right Ans - Binds
via collagen
When vessel is damaged, what two structures are exposed that contain
collagen, allowing vWF to bind? Right Ans - Basement membrane and
underlying connective tissue
What do platelets bind to in the second platelet adhesion step of primary
hemostasis? Right Ans - vWF, which is bound to collagen
,How do platelets bind vWF in second platelet adhesion step of primary
hemostasis? Right Ans - Via GP1b receptor
Name the two places where vWF comes from Right Ans - 1. Weibel-Palade
Bodies of endothelial cells
2. Alpha granules of platelets
What are the two most important factors the Weibel-Palade Bodies of
endothelial cells release? Right Ans - 1. P-selectin
2. vWF
What occurs in primary hemostasis after platelet adhesion? Right Ans -
Platelet shape change and then degranulation
What are the two most important factors released by platelets in platelet
degranulation? Right Ans - 1. ADP
2. TXA2 (thromboxane A2)
What produces thromboxane A2 in degranulation step of primary hemostasis?
Right Ans - Platelet COX
What does ADP promote in primary hemostasis? Right Ans - Platelet
expression of GPIIb/IIIa
GPIIb/IIIa vs. GPIb in primary hemostasis Right Ans - GPIb: expressed by
platelets to allow them to bind to vWF
GPIIb/IIIa: expressed by platelets after degranulation, and helps promote
platelet aggregation; induced by ADP release during degranulation
What molecule helps platelets link together during aggregation and formation
of the platelet plug? Right Ans - Fibrinogen from plasma
How is the platelet plug stabilized? Right Ans - Secondary hemostasis
(coagulation cascade)
Where does ADP in primary hemostasis come from? Right Ans - Dense
granules of platelets
, What are the two possible problems in primary hemostasis? Right Ans - 1.
Poor quantity of platelets
2. Poor quality of platelets
Name the two most important symptoms of primary hemostasis Right Ans
- 1. Mucosal bleeding
2. Skin bleeding
Symptoms of mucosal bleeding Right Ans - Epistaxis, hemoptysis, GI
bleeding, hematuria, menorrhagia, intracranial bleeding with severe
thrombocytopenia
What is epistaxis Right Ans - Nose bleed
What is the most common type of mucosal bleeding with primary hemostatic
disorders? Right Ans - Epistaxis (nose bleed)
Feared complication of severe thrombocytopenia Right Ans - Intracranial
bleeding
Name four symptoms of skin bleeding associated with primary hemostatic
disorders Right Ans - Petechiae, purpura, ecchymoses, excess bruising
Petechiae size Right Ans - 1-2 mm
Purpura size Right Ans - Over 3 mm
Ecchymoses size Right Ans - Over 1 cm
Is it a qualitative or quantitative problem with petechiae, purpura, and
ecchymoses? Right Ans - Quantitative
Normal and abnormal platelet count Right Ans - 150-400K/uL
Symptoms when under 50,000 (50 K/uL)
Normal bleeding time Right Ans - 2-7 minutes
When is normal bleeding time prolonged? Right Ans - Qualitative and
quantitative platelet disorders
What do endothelial cells sit on top of? Right Ans - Basement membrane
Hemostasis Right Ans - Mechanism of repair of blood vessel wall that
involves formation of thrombus (clot) at the site of vessel injury
What are the two stages of hemostasis? Right Ans - Primary and secondary
hemostasis
Goal of primary hemostasis Right Ans - Formation of platelet plug
What two materials interact in primary hemostasis to form the platelet plug?
Right Ans - Platelets and the vessel wall
What is the goal of secondary hemostasis? Right Ans - Stabilize the platelet
plug
What mediates secondary hemostasis? Right Ans - Coagulation cascade
Name the four steps of primary hemostasis Right Ans - 1. Transient
vasoconstriction of damage vessel
2. Platelet adhesion to the surface of disrupted vessel
3. Platelet degranulation
4. Platelet aggregation
What two things mediated transient vasoconstriction in primary hemostasis?
Right Ans - 1. Neural reflex stimulation
2. Release of endothelin from enothelial cells
In platelet adhesion, how does vWF bind to the vessel? Right Ans - Binds
via collagen
When vessel is damaged, what two structures are exposed that contain
collagen, allowing vWF to bind? Right Ans - Basement membrane and
underlying connective tissue
What do platelets bind to in the second platelet adhesion step of primary
hemostasis? Right Ans - vWF, which is bound to collagen
,How do platelets bind vWF in second platelet adhesion step of primary
hemostasis? Right Ans - Via GP1b receptor
Name the two places where vWF comes from Right Ans - 1. Weibel-Palade
Bodies of endothelial cells
2. Alpha granules of platelets
What are the two most important factors the Weibel-Palade Bodies of
endothelial cells release? Right Ans - 1. P-selectin
2. vWF
What occurs in primary hemostasis after platelet adhesion? Right Ans -
Platelet shape change and then degranulation
What are the two most important factors released by platelets in platelet
degranulation? Right Ans - 1. ADP
2. TXA2 (thromboxane A2)
What produces thromboxane A2 in degranulation step of primary hemostasis?
Right Ans - Platelet COX
What does ADP promote in primary hemostasis? Right Ans - Platelet
expression of GPIIb/IIIa
GPIIb/IIIa vs. GPIb in primary hemostasis Right Ans - GPIb: expressed by
platelets to allow them to bind to vWF
GPIIb/IIIa: expressed by platelets after degranulation, and helps promote
platelet aggregation; induced by ADP release during degranulation
What molecule helps platelets link together during aggregation and formation
of the platelet plug? Right Ans - Fibrinogen from plasma
How is the platelet plug stabilized? Right Ans - Secondary hemostasis
(coagulation cascade)
Where does ADP in primary hemostasis come from? Right Ans - Dense
granules of platelets
, What are the two possible problems in primary hemostasis? Right Ans - 1.
Poor quantity of platelets
2. Poor quality of platelets
Name the two most important symptoms of primary hemostasis Right Ans
- 1. Mucosal bleeding
2. Skin bleeding
Symptoms of mucosal bleeding Right Ans - Epistaxis, hemoptysis, GI
bleeding, hematuria, menorrhagia, intracranial bleeding with severe
thrombocytopenia
What is epistaxis Right Ans - Nose bleed
What is the most common type of mucosal bleeding with primary hemostatic
disorders? Right Ans - Epistaxis (nose bleed)
Feared complication of severe thrombocytopenia Right Ans - Intracranial
bleeding
Name four symptoms of skin bleeding associated with primary hemostatic
disorders Right Ans - Petechiae, purpura, ecchymoses, excess bruising
Petechiae size Right Ans - 1-2 mm
Purpura size Right Ans - Over 3 mm
Ecchymoses size Right Ans - Over 1 cm
Is it a qualitative or quantitative problem with petechiae, purpura, and
ecchymoses? Right Ans - Quantitative
Normal and abnormal platelet count Right Ans - 150-400K/uL
Symptoms when under 50,000 (50 K/uL)
Normal bleeding time Right Ans - 2-7 minutes
When is normal bleeding time prolonged? Right Ans - Qualitative and
quantitative platelet disorders
