Platelets

Question 1

What are platelets made from?

Answer 1

Megakaryoblasts —> Megakaryocytes

Question 2

What do megakaryocytes undergo?

Answer 2

Endomitosis (DNA doubles but cell doesn’t divide)

Question 3

What happens to the cell surface membrane?

Answer 3

It ‘blebs’ (loses fragments) ; platelets

Question 4

What is the difference in shape and form of inactive and active platelets?

Answer 4

Inactive - smooth & discoid

Active - increase SA & pseudopoid

Question 5

What do platelets release?

Answer 5

Electron dense granules (energy)

Alpha dense granules (scaffolding)

Question 6

What are electron dense granules used for and examples of them?

Answer 6

Energy to produce platelet plug

ATP, ADP, Ca2+, serotonin, thromboxane A2

Question 7

Examples of alpha dense granules

Answer 7

Platelet dense growth factor (PDGF)
VWF (vin willebrand factor)
Heparin antagonist
Fibrinogen

Question 8

What does too high a platelet level cause?

Answer 8

Thrombocytosis (increase risk of clot)
More platelet = less RBCs
More chance of platelet plug = more viscous blood

Question 9

What does too low a platelet level cause?

Answer 9

Thrombocytopenia (cut can cause increase bleeding)