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Flashcards in Platelets Deck (14):
1

What are the 3 components needed for hemostasis?

-Vessel wall
-Platelets
-Coagulation system

2

What are platelets responsible for?

Primary hemostasis

3

What are the 4 steps of primary hemostasis

1. Adhesion to collagen at the site of vascular injury
2. Additional platelets to plug the leak of the wall
3. Release of platelet contents to promote hemostasis
4. Provision of a phospholipid surface to assemble proteins of the coagulation cascade

4

Describe step 1...
-Adhesion of platelets to collagen at the site of vascular injury

-When the endometrium is disrupted, the collagen is exposed
-Platelets adhere to endothelial cells based on reaction between glycoprotein 1B and VonWillebrand Factor

5

Describe Step 2...
-Aggregation of additional platelets to "plug" the leak in the blood vessel

-Platelets activate other platelets to bind soluble molecules such as fibrinogen
-Fibrinogen acts like a bridge between the interacting platelets and the activated platelets at the binding site

6

What are platelets rich in that promotes hemostasis?

-ADP
-ATP
-Calcium
-Enzymes
-Clotting factors

7

The combination of what 2 things results in vasoconstriction?

-Clotting factors
-Prostaglandin Thromboxane A2

8

What is the point of vasoconstriction?

Controls bleeding

9

What is the goal of the phospholipid membrane?

-Organizes and promotes interactions and clotting factors

10

What does the assembly of a complex do?

-Enhances hemostatic activity and stops bleeding

11

When is the patient at risk for hemorrhage?

If they have problems with platelets, wall, or cascade

12

What is the normal platelet count?

150,000-400,000

13

When are platelet numbers a problem with surgery and trauma?

Under 50

14

When are platelet numbers a problem with spontaneous bleeding?

Under 20