NRMS 5190: Patho Final Exam Study Guide:
Disorders of Hemostasis and Blood Cells
Questions With Correct Solutions, Already
Passed!!
Suny Downstate Medical
Center
Chapter 22: Disorders of Hemostasis
What is hemostasis?
What is clot retraction?
What is clot dissolution?
What is plasminogen?
● Hemostasis
○ Refers to the stoppage of blood flow. This occurs by vessel spasm, formation of
the platelet plug, and blood coagulation or development of an insoluble fibrin clot.
○ Five Stages of Homeostasis
■ Vessel spasm
■ Formation of the platelet plug
■ Blood coagulation or development of an insoluble fibrin clot
■ Clot retraction
● Clot retraction occurs within 20-60 minutes after a clot has formed,
contributing to hemostasis by squeezing serum from the clot and
joining the edges of the broken vessel.
● Platelets also contribute to clot retraction through the action of
actin and myosin filaments. Clot retraction requires a large
number of platelets, and failure of clot retraction is indicative of a
low platelet count.
■ Clot dissolution
● Clot dissolution begins shortly after its formation.
● The process by which a clot dissolves is called fibrinolysis which is
a sequence of steps controlled by activators and inhibitors.
● Plasminogen, the proenzyme for the fibrinolytic process, normally
is present in the blood in its inactive form.
○ It is converted to its active form, plasmin, by plasminogen
activators formed in the vascular endothelium, liver, and
kidneys
■ These processes (retraction and dissolution) involve the interaction of
substrates, enzymes, protein cofactors, and calcium ions that circulate in
the blood or are released from platelets and cells in the vessel wall.
, ● Categories of hemostasis disorders
○ Thrombosis
■ The inappropriate formation of clots within the vascular system
○ Bleeding
■ Failure of blood to clot in response to appropriate stimulus
What does an injury to a blood vessel cause?
● Vascular Constriction
○ Injury to a blood vessel causes vascular smooth muscle in the vessel wall to
contract. This instantaneously reduces the flow of blood from the vessel rupture.
, ○ Both local nervous reflexes and local humoral factors such as TXA2, which is
released from platelets, contribute to the vasoconstriction.
● Platelet plug formation
What happens during platelet plug formation?
○ Seconds after vessel injury, von Willebrand factor released from the endothelium,
binds to platelet receptors causing adhesion of the platelets to the exposed
collagen fibers.
○ As the platelets adhere to the collagen fibers of the damaged vessel wall, they
become activated and release ADP and TXA, which attract additional platelets,
leading to platelet aggregation (clumping together to form a clot).
● General Forms of Hypercoagulability States
What conditions create increased platelet function?
■ Atherosclerosis
■ Diabetes mellitus
■ Smoking
■ Elevated blood lipid and cholesterol levels
■ Increased platelet levels
○ Hypercoagulability causes excessive clotting and contributes to thrombus
formation. It results from conditions that foster an increase in platelet numbers or
function or accelerated activity of the coagulation system.
○ Thrombocytosis, an elevation in the platelet count, can occur as a reactive process
(secondary thrombocytosis) or an essential process (primary thrombocytosis).
○ Increased platelet function usually results from disorders such as atherosclerosis
that damage the vascular endothelium and disturb blood flow or from conditions
such as smoking that increase sensitivity of platelets to factors that promote
adhesiveness and aggregation.
What factors lead to the development of atherosclerosis? What leads to
thrombosis?
What conditions cause accelerated activity of the coagulation system?
■ Pregnancy and the puerperium
■ Use of oral contraceptives
■ Postsurgical state
■ Immobility
■ Congestive heart failure
■ Malignant diseases
Why are people with malignant tumors more at risk?
● Some malignant tumors are thought to release tissue factor
molecules, which along with increased immobility and sepsis seen
in people with malignant disease, contribute to thrombosis in
people with these conditions.
Who is more at risk for stroke, thromboemboli and MI?
○ The risk of stroke, thromboemboli, and MI is greater in women who use oral
contraceptives, particularly over 35 and those who are smokers.
○ Hypercoagulability States
■ Increase the risk of clot or thrombus formation in the arterial or venous
circulations
, What is the difference between arterial thrombi and venous thrombi? What are these
conditions associated with?
● Arterial thrombi are associated with conditions that produce
turbulent blood flow and platelet adherence.
● Venous thrombi are associated with conditions that cause stasis of
blood flow with increased concentrations of coagulation factors
What are the causes of bleeding?
● Decrease in the number of circulating platelets
Depletion of platelets must be relatively severe before hemorrhagic
tendencies of spontaneous bleeding occur.
● Impaired platelet function
Bleeding resulting from platelet deficiency commonly occurs in
small vessels and is characterized by petechiae and purpura.
● Platelet Defects
What is considered thrombocytopenia? And What does it mean?
How can treatment of cancer affect platelets?
What is ITP (Idiopathic or immune thrombocytopenic purpura)? What are the
manifestations?
○ Thrombocytopenia
■ When there is decreased circulating platelets of less than 150K/uL on labs.
■ The lower the number of circulating platelets, the higher the risk of
bleeding.
■ There is decreased platelet production if there is loss of bone marrow
function which occurs in aplastic anemia.
● Treatment of cancer depresses bone marrow function and reduces
platelet formation.
■ Drug induced thrombocytopenia
● This can be caused by aspirin, atorvastatin and some antibiotics.
○ Once a drug is discontinued, platelet count rises.
■ ITP (Idiopathic or immune thrombocytopenic purpura)
● There is platelet antibody formation and excess destruction of
platelets.
● There may be bruising, bleeding of gums, epistaxis, melena,
abnormal menstrual bleeding. There can be purpura or petechiae as
a first sign.
■ TTP is marked by sudden and severe thrombotic involvement and is
rooted in an enzyme deficiency. It's rare.
■ What are the manifestations of Thrombocytopenia?
● Bleeding
○ Mucous membranes
■ Nose, mouth, GI Tract, Uterine Cavity
○ Commonly occurs in small vessels
■ Petechiae—pinpoint purplish-red spots
Disorders of Hemostasis and Blood Cells
Questions With Correct Solutions, Already
Passed!!
Suny Downstate Medical
Center
Chapter 22: Disorders of Hemostasis
What is hemostasis?
What is clot retraction?
What is clot dissolution?
What is plasminogen?
● Hemostasis
○ Refers to the stoppage of blood flow. This occurs by vessel spasm, formation of
the platelet plug, and blood coagulation or development of an insoluble fibrin clot.
○ Five Stages of Homeostasis
■ Vessel spasm
■ Formation of the platelet plug
■ Blood coagulation or development of an insoluble fibrin clot
■ Clot retraction
● Clot retraction occurs within 20-60 minutes after a clot has formed,
contributing to hemostasis by squeezing serum from the clot and
joining the edges of the broken vessel.
● Platelets also contribute to clot retraction through the action of
actin and myosin filaments. Clot retraction requires a large
number of platelets, and failure of clot retraction is indicative of a
low platelet count.
■ Clot dissolution
● Clot dissolution begins shortly after its formation.
● The process by which a clot dissolves is called fibrinolysis which is
a sequence of steps controlled by activators and inhibitors.
● Plasminogen, the proenzyme for the fibrinolytic process, normally
is present in the blood in its inactive form.
○ It is converted to its active form, plasmin, by plasminogen
activators formed in the vascular endothelium, liver, and
kidneys
■ These processes (retraction and dissolution) involve the interaction of
substrates, enzymes, protein cofactors, and calcium ions that circulate in
the blood or are released from platelets and cells in the vessel wall.
, ● Categories of hemostasis disorders
○ Thrombosis
■ The inappropriate formation of clots within the vascular system
○ Bleeding
■ Failure of blood to clot in response to appropriate stimulus
What does an injury to a blood vessel cause?
● Vascular Constriction
○ Injury to a blood vessel causes vascular smooth muscle in the vessel wall to
contract. This instantaneously reduces the flow of blood from the vessel rupture.
, ○ Both local nervous reflexes and local humoral factors such as TXA2, which is
released from platelets, contribute to the vasoconstriction.
● Platelet plug formation
What happens during platelet plug formation?
○ Seconds after vessel injury, von Willebrand factor released from the endothelium,
binds to platelet receptors causing adhesion of the platelets to the exposed
collagen fibers.
○ As the platelets adhere to the collagen fibers of the damaged vessel wall, they
become activated and release ADP and TXA, which attract additional platelets,
leading to platelet aggregation (clumping together to form a clot).
● General Forms of Hypercoagulability States
What conditions create increased platelet function?
■ Atherosclerosis
■ Diabetes mellitus
■ Smoking
■ Elevated blood lipid and cholesterol levels
■ Increased platelet levels
○ Hypercoagulability causes excessive clotting and contributes to thrombus
formation. It results from conditions that foster an increase in platelet numbers or
function or accelerated activity of the coagulation system.
○ Thrombocytosis, an elevation in the platelet count, can occur as a reactive process
(secondary thrombocytosis) or an essential process (primary thrombocytosis).
○ Increased platelet function usually results from disorders such as atherosclerosis
that damage the vascular endothelium and disturb blood flow or from conditions
such as smoking that increase sensitivity of platelets to factors that promote
adhesiveness and aggregation.
What factors lead to the development of atherosclerosis? What leads to
thrombosis?
What conditions cause accelerated activity of the coagulation system?
■ Pregnancy and the puerperium
■ Use of oral contraceptives
■ Postsurgical state
■ Immobility
■ Congestive heart failure
■ Malignant diseases
Why are people with malignant tumors more at risk?
● Some malignant tumors are thought to release tissue factor
molecules, which along with increased immobility and sepsis seen
in people with malignant disease, contribute to thrombosis in
people with these conditions.
Who is more at risk for stroke, thromboemboli and MI?
○ The risk of stroke, thromboemboli, and MI is greater in women who use oral
contraceptives, particularly over 35 and those who are smokers.
○ Hypercoagulability States
■ Increase the risk of clot or thrombus formation in the arterial or venous
circulations
, What is the difference between arterial thrombi and venous thrombi? What are these
conditions associated with?
● Arterial thrombi are associated with conditions that produce
turbulent blood flow and platelet adherence.
● Venous thrombi are associated with conditions that cause stasis of
blood flow with increased concentrations of coagulation factors
What are the causes of bleeding?
● Decrease in the number of circulating platelets
Depletion of platelets must be relatively severe before hemorrhagic
tendencies of spontaneous bleeding occur.
● Impaired platelet function
Bleeding resulting from platelet deficiency commonly occurs in
small vessels and is characterized by petechiae and purpura.
● Platelet Defects
What is considered thrombocytopenia? And What does it mean?
How can treatment of cancer affect platelets?
What is ITP (Idiopathic or immune thrombocytopenic purpura)? What are the
manifestations?
○ Thrombocytopenia
■ When there is decreased circulating platelets of less than 150K/uL on labs.
■ The lower the number of circulating platelets, the higher the risk of
bleeding.
■ There is decreased platelet production if there is loss of bone marrow
function which occurs in aplastic anemia.
● Treatment of cancer depresses bone marrow function and reduces
platelet formation.
■ Drug induced thrombocytopenia
● This can be caused by aspirin, atorvastatin and some antibiotics.
○ Once a drug is discontinued, platelet count rises.
■ ITP (Idiopathic or immune thrombocytopenic purpura)
● There is platelet antibody formation and excess destruction of
platelets.
● There may be bruising, bleeding of gums, epistaxis, melena,
abnormal menstrual bleeding. There can be purpura or petechiae as
a first sign.
■ TTP is marked by sudden and severe thrombotic involvement and is
rooted in an enzyme deficiency. It's rare.
■ What are the manifestations of Thrombocytopenia?
● Bleeding
○ Mucous membranes
■ Nose, mouth, GI Tract, Uterine Cavity
○ Commonly occurs in small vessels
■ Petechiae—pinpoint purplish-red spots
