6-ADD HOMEOSTASIS

Question 1

What are the three factors that depend on the ability of the extravascular hemostatic component

Answer 1

Bulk or amount of surrounding tissue+Type of tissue surrounding the injured vessel+Tone of the surrounding tissue

Question 2

What does the role of blood vessels in hemostasis depend on

Answer 2

Size+Amount of smooth muscle within their walls+Integrity of endothelial cell lining

Question 3

What are the Intravascular Components

Answer 3

Platelets and plasma proteins (procoagulants) within the blood vessels

Question 4

What are the two essential processes of hemostasis

Answer 4

Coagulation and Fibrinolysis

Question 5

What is a normal hemostatic balance

Answer 5

Coagulation = Fibrinolysis

Question 6

What conditions are associated with excessive bleeding

Answer 6

Hypocoagulable states

Question 7

What conditions are associated with uncontrolled thrombosis

Answer 7

Hypercoagulable states

Question 8

What is Hemostasis the interaction of

Answer 8

Blood vessels+platelets+coagulation mechanism+fibrinolysis

Question 9

What are the Key cellular elements of hemostasis

Answer 9

Cells of the vascular intima+Extravascular tissue factor (TF)-bearing cells+Platelets

Question 10

What are the Plasma components of hemostasis

Answer 10

Coagulation proteins+Fibrinolytic proteins+Inhibitors of coagulation and fibrinolysis

Question 11

What is Activated by desquamation and small injuries to blood vessels

Answer 11

Primary Hemostasis

Question 12

What does Primary Hemostasis involve

Answer 12

Vascular intima and platelets

Question 13

What is the speed and duration of Primary Hemostasis

Answer 13

Rapid

Question 14

What does Primary Hemostasis result in

Answer 14

Vasoconstriction and platelet plug formation

Question 15

What is Activated by large injuries to blood vessels and surrounding tissues

Answer 15

Secondary Hemostasis

Question 16

What does Secondary Hemostasis involve

Answer 16

Coagulation proteins (serine proteases)

Question 17

What is the speed and duration of Secondary Hemostasis

Answer 17

Delayed

Question 18

What does Secondary Hemostasis result in

Answer 18

Coagulation and Fibrinolysis

Question 19

What are the steps in Hemostasis After Vessel Injury

Answer 19

Vasoconstriction+Platelet Adhesion+Platelet Aggregation+Fibrin-Platelet Plug Formation+Fibrin Stabilization

Question 20

What makes up the Tunica (vascular) media

Answer 20

Smooth muscle cells (in arteries but not veins) + collagen + elastin

Question 21

What lines the vessels

Answer 21

Tunica (vascular) intima

Question 22

What does the Tunica (vascular) intima consist of

Answer 22

Single layer of endothelial cells + basement membrane + small amount of subendothelial connective tissue

Question 23

What are Endothelial cells responsible for

Answer 23

Inhibiting platelet aggregation and blood coagulation

Question 24

What do injured endothelial cells express

Answer 24

Von Willebrand factor (VWF)

Question 25

What does the expression of VWF on injured endothelial cells promote

Answer 25

Platelet adhesion

Question 26

What is the result of damage to the endothelium

Answer 26

Exposure of subendothelial collagen and tissue factor (TF)

Question 27

What are subendothelial collagen and tissue factor (TF)

Answer 27

Procoagulants

Question 28

What response does the vascular system provide against blood loss

Answer 28

Vasoconstriction

Question 29

What do smooth muscle cells release during vasoconstriction

Answer 29

Endothelin-1

Question 30

What does Endothelin-1 stimulate

Answer 30

Transient contraction of vessels (constriction) and local thrombosis

Question 31

What does vasoconstriction cause

Answer 31

Diverts blood flow away from damaged area+decreases pressure within vessel

Question 32

What cells possess receptors to TXA2 and thrombin

Answer 32

Vascular smooth muscle

Question 33

What two reactions lead to vasoconstriction

Answer 33

Neural reflexes and release of endothelin-1 from endothelial cells

Question 34

When does vessel contraction begin

Answer 34

Immediately upon vessel injury

Question 35

When is vessel contraction most effective

Answer 35

Small injuries

Question 36

What can maintain vasoconstriction

Answer 36

Systemic hormones released by adrenal glands

Question 37

What is the function of prostacyclin (PGI2) and nitric oxide

Answer 37

Inhibit platelet adhesion to endothelium+vasodilators

Question 38

Where do endothelial cells synthesize PGI2 and nitric oxide

Answer 38

From arachidonic acid using prostacyclin synthetase

Question 39

What does Heparan sulfate bind

Answer 39

Antithrombin III

Question 40

What does Antithrombin III do

Answer 40

Inactivates several serine proteases of the coagulation system

Question 41

What is Thrombomodulin

Answer 41

Receptor on endothelial cells that binds thrombin

Question 42

What is the function of the Thrombomodulin-Thrombin complex

Answer 42

Activates Protein C

Question 43

What does activated Protein C do

Answer 43

Inactivates Factors Va and VIIIa

Question 44

What is Tissue Factor Pathway Inhibitor (TFPI)

Answer 44

Binds to and inhibits the TF-VIIa complex