a. Describe the appearance of platelets and state their major function. b. Why should platelets not be called 'cells'?

Verified step by step guidance

1. insert step 1: Describe the appearance of platelets.
2. insert step 2: Explain the major function of platelets.
3. insert step 3: Discuss why platelets should not be called 'cells'.
4. insert step 4: Provide a brief explanation of the role of platelets in hemostasis.
5. insert step 5: Summarize the importance of platelets in the circulatory system.

Key Concepts

Platelet Structure

Platelets, or thrombocytes, are small, disc-shaped cell fragments derived from megakaryocytes in the bone marrow. They lack a nucleus and have a diameter of about 2-3 micrometers. Their surface is covered with glycoproteins that facilitate adhesion to blood vessels and other platelets, playing a crucial role in hemostasis.

Function of Platelets

The primary function of platelets is to prevent bleeding by forming clots at sites of vascular injury. They achieve this through a process called aggregation, where they adhere to damaged blood vessels and each other, releasing chemical signals that promote further clot formation and stabilize the hemostatic plug.

Platelets vs. Cells

Platelets are often not classified as true cells because they are anucleate and do not possess the full cellular machinery found in typical cells. Instead, they are considered cell fragments, as they originate from the cytoplasm of megakaryocytes. This distinction is important in understanding their function and role in the circulatory system.