Blood platelet

Blood platelets, also known as thrombocytes, are small, colorless cell fragments in our blood that form clots and stop or prevent bleeding. Blood platelets are part of the hematopoietic system, which regulates blood production.

Function

Blood platelets are essential for hemostasis, the process that causes bleeding to stop, and they have a significant role in the inflammatory response. When a blood vessel is damaged, platelets bind to the site of injury, change shape, and become activated to initiate the coagulation process. They release chemicals that promote clotting and contract to bring the vessel walls closer together.

Production

Platelets are produced in the bone marrow by fragmentation of megakaryocytes, a type of blood cell that has a very large size. The process of platelet production is regulated by the hormone thrombopoietin.

Disorders

There are several disorders associated with blood platelets. These include thrombocytopenia, a condition characterized by low platelet count, and thrombocytosis, which is an excessive production of platelets. Both conditions can lead to abnormal bleeding or clotting. Other disorders, such as immune thrombocytopenic purpura and thrombotic thrombocytopenic purpura, involve the immune system destroying or using up too many platelets.

Measurement

The number of platelets in the blood can be measured by a complete blood count (CBC), which is a common type of blood test. Normal platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. A count below or above this range may indicate a problem and require further testing.

See also

• Hematology
• Coagulation
• Hemostasis
• Thrombosis