Final answer:
Platelets are relatively small, with a diameter of 2-4 µm, compared to red blood cells (6-8 µm) and white blood cells (12-17 µm). They are a crucial component of the clotting process, forming clots at the site of vessel injury and stopping blood loss. They have a lifespan of about 10 days in the bloodstream before removal by macrophages.
Step-by-step explanation:
Platelets, also known as thrombocytes, are small blood components crucial to the blood clotting process. These cellular fragments are significantly smaller compared to other blood components; they measure 2-4 µm in diameter. In contrast, a red blood cell, which is donut-shaped, has a diameter of about 6-8 µm, and white blood cells are even larger, typically 12-17 µm in size. Platelets, originating from large precursor cells called megakaryocytes in the bone marrow, are abundant in the bloodstream, with a normal count ranging from 150,000 to 400,000 per microliter. Despite their small size, platelets play a vital role in halting blood loss by forming a clot at the site of vessel injury. They achieve this through the release of clotting factors and by creating a fibrin web that traps red blood cells. After serving their function in the bloodstream for about 10 days, platelets are eventually removed by macrophages, with the spleen acting as a key site for their phagocytosis.