Sun21November0437PM 15

Which of the following is true regarding platelets?

(Please select 1 option)

In a normal person are predominately found in the spleen (more than 60%)

Are formed in the bone marrow from megakaryocytes Correct

Produce prostacyclin

Contain adenosine triphosphate and serotonin

Have a lifespan in the circulation of about 30 days

Explanation

Platelets are membrane-encapsulated fragments of megakaryoctes.

Although platelets have no nucleus, they are metabolically active and are able to express membrane receptors and release stored substances when triggered. They contain adenosine diphosphate and serotonin.

However, because they have no nucleus they are unable to produce new proteins and therefore aspirin and other drugs affect function for the remainder of the platelet lifespan. Platelet lifespan is approximately 9-10 days in normal individuals.

Platelets are capable of producing nitric oxide, prostaglandins and thromboxane, but not the vasodilator prostacyclin.

Answer Statistics

1

5%

2

75%

3

5%

4

12%

5

6%

Times answered: 250