Question

Stopping bleeding in the human body requires different biological steps that are interdependent. Write an essay where you identify and explain each one of these steps. (Don’t exceed 800 words.

Answer 1

When there is bleeding in humans, there are several biological steps which are inter-related to each and helps in the process of blood clotting, aimed at preventing the loss of blood. The bleeding stops by formation of a blood clot and the steps which leads to stopping the loss of blood is called as coagulation. On speaking about blood coagulation process, it a chemical process which helps in controlling the bleeding and there are nearly 10 clotting factors which helps in preventing the clotting and loss of blood. Through these steps, the blood changes from liquid to solid at the site of injury.

The platelets play a major role in which further loss of blood is prevented and through this process, there is sealing of blood vessel which is ruptured. Generally, the process of blood loss is divided majorly into three stages

Vascular spasm – This is the first step that takes place during the injury post which the blood tends to leak out of the blood vessel. This is followed by vascular spasm in which the further blood loss is reduced by constriction of the smooth muscle along the lining of the blood vessel. The circular smooth muscle layers tend to reduce the blood flow. The endothelins are released by the vessel lining which is the probable reason for the increase in the constriction of smooth muscles of the blood vessel.

Platelet Plug formation – The second step to blood coagulation is formation of platelet plug which is initiated by the platelets. As these platelets find a site of injury, they tend to come together and aggregate and hence becomes sticky. The process of platelet aggregation is initiated by a plasma factor known as Von Willebrand factor that helps to stabilize the platelet plug. The platelet plug increases the release of many other factors which includes ADP which brings in more platelet to the injury site, serotonin which increase the vasoconstriction and increase in concentration of prostaglandins and phospholipids which helps in further clotting. The formation of the platelet plug helps in sealing the blood vessel at the site of its injury.

Coagulation – This is the third process by which the bleeding can be stopped through formation of blood clot. In this there are many factors which are involved and there are 12 clotting factors which helps in the final coagulation process. The factor X is activated and this the prothrombinase to convert the prothrombin into thrombin which is the active form. The thrombin converts the fibrinogen into fibrin and this helps in securing the platelets together and form the fibrin clot.