Ch 13: Platelets

Question 1

Where do platelets come from?

Answer 1

megakaryocytes in the bone marrow

Question 2

What are the normal size of platelets?

Answer 2

2.5 um

Question 3

What is the normal reference range for platelets?

Answer 3

150-400,000. 21 per 100x field

Question 4

Explain adhesion, aggregation, and secretion?

Answer 4

Adhesion: the process used to repair injury to blood vessel lining
Aggregation: extensive vessel damage, platelets adhere and aggregate
Secretion-Activated platelets release granular contents

Question 5

What compounds are important in aggregation?

Answer 5

VWF a clotting factor only protein present in the first stage of hemostasis “white clot”. , attaches itself to inactive fragments and creates a layer to fill space of injury.
Fibrin, works with RBCs to deposit around injury creating red clot

Question 6

What compounds are important in adhesion?

Answer 6

CAM integrin (leucine rich family), bind collagen enable platelet to adhere to injured blood vessel.

Question 7

What is platelet shedding

Answer 7

Megakaryocytes use DNA to synthesize an abundant amount of cytoplasm called proplatelets. They do this when maturing, they spread through epithelial cells and extend into venous blood to release the platelets. thrombocytopoesis

Question 8

What is a reticulated platelet?

Answer 8

larger mature platelets that are released into the blood if there is thrombocytopenia (low platelet count)

Question 9

Why does the spleen release platelets after a trauma?

Answer 9

To make up for lost blood and start clotting to avoid losing more.

Question 10

What are the characteristics of platelets

Answer 10

granular cytoplasm with a membrane but no nucleus, biconvex

Question 11

How many platelets are in circulating blood and how many are in the spleen

Answer 11

1/3 in spleen

2/3 in circulating blood

Question 12

What causes the spleen to release its storage of platelets

Answer 12

acute inflammation, an injury or surgery, after plateletpheresis

Question 13

What is plateletpheresis

Answer 13

The procedure where all the platelets in blood are removed, cleaned and sent back into the body.

Question 14

What is splenomegaly/ hyperspenism?

Answer 14

the inflammation of the spleen because it is sequestering too many platelets

Question 15

What compounds are important in secretion

Answer 15

CAM selectin: releases granular substance

Question 16

What is DVT deep vein thrombosis

Answer 16

when a blood clot breaks off and is loose in the circulatory system. can cause pulmonary embolism if it reaches lungs or stoke if brain

Question 17

What does heprine do?

Answer 17

anticoagulant that prevents blood clotting.

Question 18

What precursor are platelets from?

Answer 18

common myeloid precursor

Question 19

How big is a platelet that is too big

Answer 19

6 um, must be noted if found when doing blood smear in morphology analysis