Platelets

Question 1

what are platelets also known as

Answer 1

thrombocytes

Question 2

platelets are pieces of cytoplasm (not complete cells) that bud off from what giant cell

Answer 2

megakaryocytes

Question 3

how do platelets appear on a blood smear

Answer 3

non-nucleated, round to oval in shape, clear cytoplasm that contains small blue to purple granules

Question 4

the size of platelets vary by what

Answer 4

species

Question 5

usually platelets are smaller than what

Answer 5

RBC

Question 6

giant platelets

Answer 6

macroplatelets

Question 7

macroplatelets are released into circulation when

Answer 7

when there is an increased consumption somewhere in the body

Question 8

platelets are most important for what in the body

Answer 8

hemostasis

Question 9

what are two specific functions of platelets in hemostasis

Answer 9

(part of the clotting process)
formation of a platelet plug
stabilization of the plug - making it irreversible

Question 10

three steps of the clotting process

Answer 10

Platelet adhesion
Platelet aggression
Thrombin is formed

Question 11

the formation of thrombin also converts _______ to strands of _________

Answer 11

fibrinogen
fibrin

Question 12

fibrin attaches to where

Answer 12

platelet surface

Question 13

a series of reactions that result in inactive enzymes being activated by the preceding enzyme in the order

Answer 13

coagulation cascade

Question 14

how many different factors have been identified as necessary for the clotting process to take place

Answer 14

13

Question 15

the coagulation cascade generates large quantities of what

Answer 15

fibrin

Question 16

where does fibrin attach in the coagulation cascade

Answer 16

on the aggregated platelets surface

Question 17

the generation of fibrin prevents what

Answer 17

further escape of blood

Question 18

acts as scaffolding for repair of damaged vessel

Answer 18

fibrin

Question 19

at the same time the clot is formed, what does the endothelium produce that will eventually dissolve the clot when the endothelium has been repaired

Answer 19

fibrinolysis

Question 20

the absence of platelet adhesion can result in what

Answer 20

bleeding disorders

Question 21

small hemorrhages on the skin

Answer 21

petechiae

Question 22

inadequate platelets can cause what to migrate through the endothelial wall and cause petechiae

Answer 22

RBC

Question 23

how long do platelets circulate in the blood

Answer 23

5 to 7 days

Question 24

the liver produces what, that regulates the number of platelets circulating in the body

Answer 24

thrombopoietin

Question 25

platelets are removed from circulation by what, because of old age

Answer 25

macrophages