Blodplättar

Verilettu

Blodplättar or platelets are small, colorless cell fragments in the blood that are essential for blood clotting (coagulation). They form clots to stop bleeding when a blood vessel is injured. Platelets are produced in the bone marrow from a type of stem cell called a megakaryocyte. The process of platelet formation is known as thrombopoiesis.

Function

The primary function of platelets is to prevent bleeding by forming blood clots. When a blood vessel is damaged, platelets adhere to the site of injury and to each other, forming a temporary plug. They also release chemicals that promote blood clotting by activating additional platelets and stabilizing the clot. Platelets play a crucial role in the coagulation cascade, a complex series of events that leads to the formation of a stable clot.

Structure

Platelets are the smallest of the blood cells, with a diameter of 2–3 micrometers. Unlike red blood cells and white blood cells, platelets do not have a nucleus. They contain granules filled with substances that are important for clotting and repairing blood vessels. These include serotonin, calcium, enzymes, growth factors, and ADP (adenosine diphosphate).

Life Cycle

Platelets circulate in the blood for about 7–10 days before being removed by the spleen. The average lifespan of a platelet is relatively short compared to other blood cells. The body constantly produces new platelets to maintain a normal count, which ranges from 150,000 to 450,000 platelets per microliter of blood.

Disorders

Platelet disorders can lead to problems with clotting, resulting in either too much bleeding or excessive clotting. Conditions associated with low platelet counts include thrombocytopenia, which can result from a variety of causes such as bone marrow disorders, certain medications, and diseases. High platelet counts, known as thrombocytosis, can increase the risk of thrombosis, leading to potentially life-threatening conditions like strokes and heart attacks.

Diagnosis and Treatment

Platelet count and function can be assessed through blood tests. Treatment for platelet disorders depends on the underlying cause. It may include medications to increase or decrease platelet production, blood transfusions, or procedures to remove excess platelets. In cases of severe bleeding, platelet transfusions may be necessary.