Video 7 Blood Platelets Function

Показать описание

07) Platelets

Platelets provide critical protection for our blood vessel walls, helping clog wounds and stopping the loss of blood.

Platelets are not completely formed cells, but merely cell fragments and consequently much smaller than red cells. They account for less than one percent of total blood volume and live for about 10 days.

Let's take a closer look at how the clotting process works. When a blood vessel wall ruptures, it causes the blood to be exposed to collagen, which is the most abundant protein in the body, found in muscles, skin and other tissues.

Special receptors on the surface of collagen molecules are matched to detect and bind to platelets, so that if the vessel wall is ruptured and platelets come into contact with the collagen they will bind to it and accumulate. This accumulation is further enhanced by the reaction of clotting factors in the plasma, which react and assist with attracting more platelets to the wound site.

In addition, soluable fibrinogen proteins found in the blood plasma are also attracted to the wound site, where they are used by the platelets to create an insoluable web-like structure over the wound area, trapping red cells. The combination of these actions forms a hardening process that creates a scab that will eventually fall off as the ruptured vessel wall and skin tissue are repaired.