NURS 5315: Advanced Pathophysiology - Hematologic Module 4 Study
Questions
What is the peripheral zone of a platelet?
The peripheral zone is the outermost layer of a platelet. It consists of phospholipids
and contains numerous receptors that are essential for platelet adhesion and
aggregation.
What is the sol-gel zone of the platelet?
The sol-gel zone is the outermost region of the platelet, containing many receptors
that support platelet adhesion and aggregation.
What is the organelle zone of platelets?
The innermost layer of the platelet, called the organelle zone, holds calcium-dense
granules and alpha granules.
What are the four phases of platelet plug formation?
The four phases are activation, adherence, aggregation, and secretion.
What is the first phase of platelet plug formation, and how does it work?
The first phase is activation. Under normal conditions, platelets circulate without
sticking to the endothelial lining. However, when endothelial injury exposes von
Willebrand factor (vWF), fibronectin, collagen, and thrombospondin, platelets
become activated. Collagen, in particular, is a strong activator. Upon exposure to the
subendothelial collagen, platelets undergo a shape change that enhances their ability
to stick to the injury site.
What happens during the second phase of platelet plug formation?
The second phase is adherence. Platelets attach to the injured endothelial surface,
starting with vWF binding to the exposed collagen. vWF then binds to the GP Ib/IX/V
receptors on platelets, while collagen binds to the GP VI receptor. This binding
activates the GPIIb/IIIa and GPIa/IIa receptors, helping anchor the platelets in place.
What happens during the third phase of platelet plug formation?
During aggregation, platelets stick together. Once activated, GPIIb/IIIa receptors on
platelets have a higher affinity for fibrinogen. Fibrinogen binds to two GPIIb/IIIa
receptors, linking the platelets together.
What happens during the fourth phase of platelet plug formation?
In the secretion phase, platelet granules release their contents, including:
• ADP: Enhances adhesion, activates platelets, and recruits more platelets.
• Serotonin: Helps recruit more platelets.
• Fibronectin and thrombospondin: Stabilize adhered platelets.
• Thromboxane A2: Induces vasoconstriction and amplifies platelet aggregation.
• Growth factors: Aid tissue repair but also contribute to atherosclerosis development.
,What happens in the final step of platelet plug formation?
The platelet plug is stabilized by fibrin, which is formed by activated factor XIIIa,
marking the final step in the process.
What is the extrinsic pathway in the coagulation cascade?
The extrinsic pathway is the main coagulation pathway, triggered when tissue factor
(TF) is exposed at the site of injury. TF binds with factor VII to form the TF/VIIa
complex, which activates factor X to Xa. Activated Xa forms the prothrombinase
complex with activated factor Va and calcium, converting prothrombin (factor II) to
thrombin. Thrombin activates several factors, including fibrinogen (factor I), which is
converted into fibrin to stabilize the platelet plug.
What is the intrinsic pathway in the coagulation cascade?
The intrinsic pathway enhances the extrinsic pathway and is activated when blood
comes into contact with negative charges from molecules like ADP and ATP. This
activates factor XII (Hageman factor), which then activates factor XI, which in turn
activates factor IX. Activated factor IXa activates factor X, leading to the formation
of the prothrombinase complex and the common coagulation pathway.
Key Plasma Proteins in Coagulation:
1. Tissue Factor
2. Factor VII
3. Factor X
4. Prothrombinase Complex
5. Prothrombin (Factor II)
6. Thrombin
7. Fibrinogen
8. Fibrin
9. Factor XIII
10. Factor XII
11. Factor VIII
12. Factor IX
13. Antithrombin
14. Protein C
15. Protein S
16. t-PA
What is the coagulation cascade?
The coagulation cascade is part of the hemostatic process that leads to the formation
of a blood clot. It consists of two pathways—the extrinsic and intrinsic pathways—
that converge at the common pathway. This cascade results in fibrin formation, which
stabilizes the platelet plug and prevents further bleeding. The process involves 12
coagulation factors, most of which are produced in the liver. Therefore, liver diseases
can lead to deficiencies in these factors, increasing the risk of bleeding.
How does aspirin affect the platelet plug formation process?
Aspirin inhibits thromboxane A2 (TXA2) formation by blocking the COX-1 pathway
in the arachidonic acid pathway. This reduces platelet aggregation and can prevent
excessive clot formation.
, This version is more fluid, with slightly altered phrasing to make it sound more like it
was written by a human.
What is the intrinsic pathway arms of the coagulation cascade
The clinical significance of the intrinsic pathway is not entirely understood, because a deficiency of
factor XII (Hageman factor) does not cause bleeding. As such the intrinsic pathway's main function is
thought to be one which enhances the extrinsic pathway. This pathway is activated when the blood is
exposed to negative charges which are found on the molecules of ADP and ATP. This exposure
activates factor XII (Hageman factor). Activated factor XIIa then activates factor XI. Activated factor
XIa activates IX. Activated factor IXa then activates factor X. Activated factor Xa then forms the
prothrombinase complex in the common pathway.
Coagulation Cascade Key Plasma Proteins
1.Tissue Factor
2.VII
3.X
4 .Prothrombinase Complex
5. Prothrombin
6. Thrombin
7 .Fibrinogen
8. Fibrin
9. XIII
10. XII
11. VIII
12. IX
13. Antithrombin
14. Protein C
15. Protein S
16.t-PA
1. Initiator of extrinsic pathway.
2. Forms complex with tissue factor (III) and activates factors IX and X
3. Activates Prothrombin through activated Xa form
4. (prothrombin and activated factors X and V) that activates prothrombin into thrombin
5. Factor II, source of thrombin that activates fibrinogen
6. cleaves the extracellular domain of G-protein-coupled protease-activated receptors (PARs),
thereby initiating transmembrane signaling.
7. moves between the beta and gamma regions but is removed during the formation of serum;
precursor of fibrin clot
8. Used to stabilize clot
9. Fibrin - stabilizing factor - cross links fibrin through XIIIa to strengthen clot
10. Hageman Factor. Initiator of intrinsic pathway
11. VIIIa is a component of tenase complex
12. IXa is a component of tenase complex, activates factor X
13. it inhibits thrombin and several activated clotting factors (e.g., VIIa, IXa, Xa, XIa, XIIa).
14. in the circulation binds to thrombomodulin in a thrombin-dependent manner and is converted to
activated protein C
15. degrades factors Va and VIIIa
16. a serine protease that reaches maximal enzymatic activity after binding to fibrin and
proteolytically activates plasminogen to plasmin
What is the coagulation cascade
The coagulation cascade is the second arm of hemostasis. This process involves quite a few steps and
there are many players involved. It can be difficult to follow and understand. This first slide show the
Questions
What is the peripheral zone of a platelet?
The peripheral zone is the outermost layer of a platelet. It consists of phospholipids
and contains numerous receptors that are essential for platelet adhesion and
aggregation.
What is the sol-gel zone of the platelet?
The sol-gel zone is the outermost region of the platelet, containing many receptors
that support platelet adhesion and aggregation.
What is the organelle zone of platelets?
The innermost layer of the platelet, called the organelle zone, holds calcium-dense
granules and alpha granules.
What are the four phases of platelet plug formation?
The four phases are activation, adherence, aggregation, and secretion.
What is the first phase of platelet plug formation, and how does it work?
The first phase is activation. Under normal conditions, platelets circulate without
sticking to the endothelial lining. However, when endothelial injury exposes von
Willebrand factor (vWF), fibronectin, collagen, and thrombospondin, platelets
become activated. Collagen, in particular, is a strong activator. Upon exposure to the
subendothelial collagen, platelets undergo a shape change that enhances their ability
to stick to the injury site.
What happens during the second phase of platelet plug formation?
The second phase is adherence. Platelets attach to the injured endothelial surface,
starting with vWF binding to the exposed collagen. vWF then binds to the GP Ib/IX/V
receptors on platelets, while collagen binds to the GP VI receptor. This binding
activates the GPIIb/IIIa and GPIa/IIa receptors, helping anchor the platelets in place.
What happens during the third phase of platelet plug formation?
During aggregation, platelets stick together. Once activated, GPIIb/IIIa receptors on
platelets have a higher affinity for fibrinogen. Fibrinogen binds to two GPIIb/IIIa
receptors, linking the platelets together.
What happens during the fourth phase of platelet plug formation?
In the secretion phase, platelet granules release their contents, including:
• ADP: Enhances adhesion, activates platelets, and recruits more platelets.
• Serotonin: Helps recruit more platelets.
• Fibronectin and thrombospondin: Stabilize adhered platelets.
• Thromboxane A2: Induces vasoconstriction and amplifies platelet aggregation.
• Growth factors: Aid tissue repair but also contribute to atherosclerosis development.
,What happens in the final step of platelet plug formation?
The platelet plug is stabilized by fibrin, which is formed by activated factor XIIIa,
marking the final step in the process.
What is the extrinsic pathway in the coagulation cascade?
The extrinsic pathway is the main coagulation pathway, triggered when tissue factor
(TF) is exposed at the site of injury. TF binds with factor VII to form the TF/VIIa
complex, which activates factor X to Xa. Activated Xa forms the prothrombinase
complex with activated factor Va and calcium, converting prothrombin (factor II) to
thrombin. Thrombin activates several factors, including fibrinogen (factor I), which is
converted into fibrin to stabilize the platelet plug.
What is the intrinsic pathway in the coagulation cascade?
The intrinsic pathway enhances the extrinsic pathway and is activated when blood
comes into contact with negative charges from molecules like ADP and ATP. This
activates factor XII (Hageman factor), which then activates factor XI, which in turn
activates factor IX. Activated factor IXa activates factor X, leading to the formation
of the prothrombinase complex and the common coagulation pathway.
Key Plasma Proteins in Coagulation:
1. Tissue Factor
2. Factor VII
3. Factor X
4. Prothrombinase Complex
5. Prothrombin (Factor II)
6. Thrombin
7. Fibrinogen
8. Fibrin
9. Factor XIII
10. Factor XII
11. Factor VIII
12. Factor IX
13. Antithrombin
14. Protein C
15. Protein S
16. t-PA
What is the coagulation cascade?
The coagulation cascade is part of the hemostatic process that leads to the formation
of a blood clot. It consists of two pathways—the extrinsic and intrinsic pathways—
that converge at the common pathway. This cascade results in fibrin formation, which
stabilizes the platelet plug and prevents further bleeding. The process involves 12
coagulation factors, most of which are produced in the liver. Therefore, liver diseases
can lead to deficiencies in these factors, increasing the risk of bleeding.
How does aspirin affect the platelet plug formation process?
Aspirin inhibits thromboxane A2 (TXA2) formation by blocking the COX-1 pathway
in the arachidonic acid pathway. This reduces platelet aggregation and can prevent
excessive clot formation.
, This version is more fluid, with slightly altered phrasing to make it sound more like it
was written by a human.
What is the intrinsic pathway arms of the coagulation cascade
The clinical significance of the intrinsic pathway is not entirely understood, because a deficiency of
factor XII (Hageman factor) does not cause bleeding. As such the intrinsic pathway's main function is
thought to be one which enhances the extrinsic pathway. This pathway is activated when the blood is
exposed to negative charges which are found on the molecules of ADP and ATP. This exposure
activates factor XII (Hageman factor). Activated factor XIIa then activates factor XI. Activated factor
XIa activates IX. Activated factor IXa then activates factor X. Activated factor Xa then forms the
prothrombinase complex in the common pathway.
Coagulation Cascade Key Plasma Proteins
1.Tissue Factor
2.VII
3.X
4 .Prothrombinase Complex
5. Prothrombin
6. Thrombin
7 .Fibrinogen
8. Fibrin
9. XIII
10. XII
11. VIII
12. IX
13. Antithrombin
14. Protein C
15. Protein S
16.t-PA
1. Initiator of extrinsic pathway.
2. Forms complex with tissue factor (III) and activates factors IX and X
3. Activates Prothrombin through activated Xa form
4. (prothrombin and activated factors X and V) that activates prothrombin into thrombin
5. Factor II, source of thrombin that activates fibrinogen
6. cleaves the extracellular domain of G-protein-coupled protease-activated receptors (PARs),
thereby initiating transmembrane signaling.
7. moves between the beta and gamma regions but is removed during the formation of serum;
precursor of fibrin clot
8. Used to stabilize clot
9. Fibrin - stabilizing factor - cross links fibrin through XIIIa to strengthen clot
10. Hageman Factor. Initiator of intrinsic pathway
11. VIIIa is a component of tenase complex
12. IXa is a component of tenase complex, activates factor X
13. it inhibits thrombin and several activated clotting factors (e.g., VIIa, IXa, Xa, XIa, XIIa).
14. in the circulation binds to thrombomodulin in a thrombin-dependent manner and is converted to
activated protein C
15. degrades factors Va and VIIIa
16. a serine protease that reaches maximal enzymatic activity after binding to fibrin and
proteolytically activates plasminogen to plasmin
What is the coagulation cascade
The coagulation cascade is the second arm of hemostasis. This process involves quite a few steps and
there are many players involved. It can be difficult to follow and understand. This first slide show the
