portsample.blogg.se - Blood cell fragments used to clot blood are called

They may even look like an octopus, with long tentacles reaching out to make contact with the broken blood vessel wall or with other platelets.

They become round and extend long filaments. When platelets are stimulated by a break in the blood vessel wall they change shape as shown in the other three pictures. They are shaped like a plate, therefore their name. The pictures above show normal platelets on the left. Also platelets contain proteins similar to muscle proteins that allow them to change shape when they become sticky. They contain granules that can secrete other proteins required for creating a firm plug to seal blood vessel breaks. They contain proteins on their surface that allow them to stick to breaks in the blood vessel wall and also to stick to each other. But even though platelets are merely cell fragments, they contain many structures that are critical to stop bleeding. Platelets are actually not true cells but merely circulating fragments of cells. The dominant hormone controlling megakaryocyte development is thrombopoietin (often abbreviated as TPO). As megakaryocytes develop into giant cells, they undergo a process of fragmentation that results in the release of over 1,000 platelets per megakaryocyte. Platelets are produced from very large bone marrow cells called megakaryocytes. Platelets are produced in the bone marrow, the same as the red cells and most of the white blood cells. There are several different types of white cells but all are related to immunity and fighting infection. There are only 5,000 to 10,000 white blood cells per microliter.

White blood cells are the largest of the blood cells but also the fewest.

With microscopic examination, they look like a red or orange tire with a thin, almost transparent center. Red cells are normally shaped as round, biconcave discs. Hemoglobin is the critical protein that transports oxygen from our lungs to the tissues. Their color is caused by hemoglobin, which accounts for nearly all of the red cell volume. Red blood cells make up about 40% of our total blood volume, a measure called the hematocrit.

Red blood cells are the most numerous blood cell, about 5,000,000 per microliter.

The principal function of platelets is to prevent bleeding. The normal platelet count is 150,000-350,000 per microliter of blood, but since platelets are so small, they make up just a tiny fraction of the blood volume. Platelets are only about 20% of the diameter of red blood cells.Platelets are the smallest of the three major types of blood cells. In this section we introduce platelets themselves.