Vascular Part 1

Question 1

State five reasons why a thrombus does not normally form in intact vessels.

Answer 1

• Smooth surface
• Prostacyclin
• heparan sulfate
• tissue factor pathway inhibitor (TFPI)
• Thrombomodulin

Question 2

Platelete activation inhibitor

Answer 2

Prostacyclin

Question 3

Activates antithrombin

Answer 3

Heparan sulfate

Question 4

Inactivates VIIa…controls TF/extrinsic pathway

Answer 4

TFPI- Tissue factor pathway inhibitor

Question 5

Activates protein C pathway

Answer 5

Thrombomodulin

Question 6

State four procoagulant properties of the vascular intima that lend to thrombus formation during vascular damage.

Answer 6

• Vasoconstriction
• Basement membrane exposes collagen
• von Willebrand factor secreted
• Tissue factor exposed

Question 7

Necessary for platelets to adhere to subendothelial collagen in arterioles; (and eventual) platelet aggregation.

Answer 7

von Willebrand factor secreted

Question 8

Activates plasma coagulation system (factor VII)

Answer 8

Tissue factor exposed

Question 9

Discuss thrombopoiesis:

List the four stages of maturation.

Answer 9

• Megakaryoblast
• promegakaryocyte
• megakaryocyte
• platelets (thrombocytes)

Question 10

Nucleus round; 2-6 nucleoli; chromatin is homogeneous, loosely organized; cystoplasm basophilic

Answer 10

Megakaryoblast

Question 11

Nucleus indented; nucleoli are variable; chromatin is condensed and cytoplasm is basophilic

Answer 11

Promegakaryocyte

Question 12

Nucleus-2-32 lobes (8 lobes are most common); cytoplasm is blue to pink and abundant; granules reddish blue.

Answer 12

Megakaryocyte

Question 13

No nucleus; light blue to colorless cytoplasm; red to violet, abundant granules.

Answer 13

Platelet (thrombocytes)

Question 14

Regulatory mechanism of thrombopoiesis.

Answer 14

Growth factor, specifically hormone called thrombopoietin

Question 15

Sites of platelet production

Answer 15

Medullary=BM; extramedullary=lungs

Question 16

Describe the morphology of a normal platelet when stained with wright’s stain.

Answer 16

chromomere aka granulomere; Hyalomere

Outside of platelets is light color and round

Question 17

Name the two pools into which platelets are distributed

Answer 17

Circulatory pool (2/3) and splenic pool (1/3)

Question 18

state the average life span of the platelet

Answer 18

8-12 days

Question 19

Discuss four platelet functions.

Answer 19

Source of PF3
Source of PF4
Maintain vessel integrity
formation of platelet plug

Question 20

Phospholipid found within platelet membrane and is essential reaction site in the cascade.

Answer 20

source of PF 3

Question 21

Protein found in platelet’s alpha granules and is capable of neutralizing heparin

Answer 21

Source of PF 4

Question 22

What is the job of maintaining vessel integrity in platelet?

Answer 22

Platelets adhere to the subendothelial collagen, and fill in the gaps until new endothelial cells grow

Question 23

List four causes of platelet activation caused by traumatic venipuncture and/or shaking of the sodium citrate tube

Answer 23

Subsequent release of PF4
PF4 will neutralize heparin in blood sample
falsely shorten APTT
potential for subsequent over anticoagulation of the paitent

Question 24

In the formation of the platelet plug: Is it primary or secondary hemostasis?

Answer 24

Primary

Question 25

In the formation of the platelet plug: does it have short or long term effect?

Answer 25

Short term effect

Question 26

In the formation of the platelet plug: list two hemostatic systems involved in primary hemostasis?

Answer 26

Vascular intimia and Platelets

Question 27

In the formation of the platelet plug: List type of bleeding with disorder of Primary hemostasis?

Answer 27

Temporarily arrests bleeding; excessive bruising & mucocutaenouse

Question 28

In the formation of the platelet plug: type of test are used for diagnostic purposes?

Answer 28

Platelet tests

Question 29

List the three steps involved in primary hemostasis.

Answer 29

Platelet adhesion
Platelet activation
Platelet aggregation

Question 30

Discuss the platelet adhesion.

Answer 30

• Platelets first adhere to collagen
  
  • GPIb binds platelet to vWF (bridge)
  • GPIb/IX necessary to attach vWF bridge to the subendothelium for platelet adhesion

Question 31

Discuss the platelet activation.

Answer 31

Platelets release procoagulant factors and synthesize prostaglandins to activate platelets

Question 32

Discuss the platelet aggregation

Answer 32

Fibrinogen bridge and glycoprotein IIB/IIIa complex needed for platelets to attach to one another that is platelet aggregation

Question 33

List three zones of platelet ultrastructure.

Answer 33

Peripheral zone
Sol-gel zone
Organelle Zone

Question 34

Functions as receptor and transmitter region as well as it is essential for adhesion and aggregation.

Answer 34

Peripheral zone

Question 35

Functions as cytoskeletal/contractile region.

Answer 35

Sol gel zone

Question 36

Functions as metabolic/organelle region and has two types of granules.

Answer 36

Organelle zone

Question 37

List two types of granules in organelle zone

Answer 37

Alpha and Dense bodies

Question 38

Differentiate quantitative vs. qualitative platelet testing.

Answer 38

Quantitative tests– number!!
- Platelet count or slide estimate
Qualitative Tests- Function!!
- Bleeding time, platelet function analyzer (PFA-100), platelet aggregation, clot retraction

Question 39

Indicate why EDTA is the anticoagulant of choice when performing electronic platelets counts.

Answer 39

It prevents the clumping of platelets