Platelets

Question 1

Platelets are not cells but are _

Answer 1

fragments

Question 2

What are platelets

Answer 2

membrane bound pieces of cytoplasm

Question 3

Platelets lack a _ but contain _

Answer 3

nucleus; granules

Question 4

Megakaryocytes form in the _ _ from PPSC due to chemical, thrombopoitetin

Answer 4

bone marrow

Question 5

What two mechanisms are platelets formed by

Answer 5

budding off surface of megakaryocyte and cytoplasm of megakaryocyte splits off

Question 6

_ is a chemical which is usually associated with a platelet

Answer 6

Thrombopoietin

Question 7

When the thrombopoietin is release (becomes free thrombopoietin) it stimulates the _ _

Answer 7

bone marrow

Question 8

How long do platelets last in circulation

Answer 8

10-14 days

Question 9

Spleen stores _ of total platelets

Answer 9

1/3

Question 10

Platelet functions

Answer 10

1.Form platelet plug in primary hemostasis
2.Stimulate secondary hemostasis
3.Stimulate neovascularization

Question 11

What is hemostasis

Answer 11

maintenance of blood volume

Question 12

3 components of hemostasis

Answer 12

1. Vascular integrity
   2.Platelet number and function
   3.Coagulation factors

Question 13

Why are cat platelet counts difficult

Answer 13

because they are large and hard for machine to differentiate from RBCs

Question 14

What is the normal range for platelets?

Answer 14

200,000-500,000 plt/uL for all species

Question 15

What is the term for less than normal range of platelets

Answer 15

thrombocytopenia

Question 16

What is the term for greater than normal range of platelets

Answer 16

thrombocytosis

Question 17

When would you HAVE to use a platelet estimate because a count won’t work?

Answer 17

platelet clumping

Question 18

If less than 7 plt/field (without clumping on feathered edge)= appears _

Answer 18

decreased

Question 19

Secondary hemostasis occurs in the _

Answer 19

liver

Question 20

If greater than 21plt/field = appears _

Answer 20

increase

Question 21

How should platelets be examined

Answer 21

-Monoloayer
-100x (oil)
-5-10 fields to judge

Question 22

If platelets consistently the same size as RBCs or even bigger- can use one of these terms:

Answer 22

-Megaplatelet
-Large platelet
-Giant platelet

Question 23

If membrane irregular = _ _

Answer 23

reactive platelet

Question 24

Some stimulus causes increased surface area for _ and _

Answer 24

adhesion and aggregation

Question 25

Decreased production of platelets indicates

Answer 25

bone marrow toxins or infections

Question 26

Increase utilization (consumption) indicates

Answer 26

blood loss; DIC

Question 27

Increased destruction of platelets indicates

Answer 27

Immune-mediated problem

Question 28

Increase sequestration of platelets indicates

Answer 28

-Splenomegaly, endoteoxemia, hepotmegaly, hypothermia

Question 29

Most common cause of thrombocytosis

Answer 29

traumatic venipuncture

Question 30

Thrombocytosis can also occur with

Answer 30

excitement (splenic contraction), elevated glucocorticoids, splenectomy, fractures

Question 31

Why is MPV not useful in cats

Answer 31

cats have larger platelets

Question 32

Breed that usually has increase MPV

Answer 32

cavalier King Charles spaniels

Question 33

increased MPV can also be expected with ,, or _

Answer 33

increased loss, destruction, or consumption

Question 34

High MPV indicates adequate _ _ response; however, normal or low does not predict a low _ _ response

Answer 34

bone marrow

Question 35

What is plateletcrit or thrombocrit

Answer 35

measure of the percentage of the total blood volume comprise of platelets

Question 36

How is plateletcrit or thrombocrit determined

Answer 36

multiplying total plt count by MPV

Question 37

Plateletcrit or thrombocrit is normally less than _ in most mammals

Answer 37

1%