Platelets

Question 1

Quantity

Answer 1

150-450 thousand/mm^3

Question 2

Life Span

Answer 2

10 days

Question 3

% in circulation

Answer 3

80

Question 4

% in spleen

Answer 4

20

Question 5

Anatomy

Answer 5

Peripheral Zone, Sol Gel Zone, Organelle Zone

Question 6

Peripheral Zone

Answer 6

Glycoprotein
Unit Membrane
Submembrane Area

Question 7

Glycoprotein

Answer 7

serves as a receptor and facilitates transmission of stimuli across the platelet membrane; contains the 2b/3a receptor for fibrinogen

Question 8

Unit Membrane

Answer 8

phospholipid - PF3

Question 9

Submembrane area

Answer 9

submembrane filaments (pseudopod formation)
open canicular systems

Question 10

Sol Gel Zone

Answer 10

contraction and support - microtubules

Question 11

Organelle Zone

Answer 11

storage and excretion

Granules (alpha and beta), Mitochondria, Glycogen, Golgi

Question 12

Alpha Granules

Answer 12

release II reaction, contains beta thromoglobulin to inhibit prostacyclin that inhibits platelet adhesion

Question 13

Dense Bodies

Answer 13

release I reaction, contains ADP that causes platelet aggregation

Question 14

ADP

Answer 14

causes thromboxane formation (more potent)

Question 15

Aspirin

Answer 15

inhibits Cox-1 which inhibits thromboxane

Question 16

Platelet estimate

Answer 16

average # of platelets in oil and multiply by 20,000

Question 17

Platelet Measurements

Answer 17

estimate the # of platelets by examination of peripheral blood smear - good smear has a feathered edge

Question 18

Bleeding Time

Answer 18

shows how the platelets are functioning; can be affected by the PLT count; 2-10 mins

Question 19

Aggregatory agents used

Answer 19

ADP, Collagen, Epinephrine, Thrombin, Ristocetin, Arachidonic Acid