Know how blood clots so fast

This article is in continuation to the previous article that focused on body fluids and circulation. In today’s article, we will discuss coagulation of blood and lymph. Coagulation of blood You know that when you cut your finger or hurt yourself, your wound does not continue to bleed for a long time; usually the blood […]

This article is in continuation to the previous article that focused on body fluids and circulation. In today’s article, we will discuss coagulation of blood and lymph.

Coagulation of blood

You know that when you cut your finger or hurt yourself, your wound does not continue to bleed for a long time; usually the blood stops flowing after sometime. Do you know why? Blood exhibits coagulation or clotting in response to an injury or trauma. This is a mechanism to prevent excessive loss of blood from the body.

• You would have observed a dark reddish-brown scum formed at the site of a cut or an injury over a period of time. It is a clot or coagulam formed mainly of a network of threads called fibrins in which dead and damaged formed elements of blood are trapped.

• Fibrins are formed by the conversion of inactive fibrinogens in the plasma by the enzyme thrombin.

• Thrombins, in turn, are formed from another inactive substance present in the plasma called prothrombin. An enzyme complex, thrombokinase, is required for the above reaction.

• This complex is formed by a series of linked enzymic reactions (cascade process) involving a number of factors present in the plasma in an inactive state.

• An injury or a trauma stimulates the platelets in the blood to release certain factors which activate the mechanism of coagulation.

• Certain factors released by the tissues at the site of injury also can initiate coagulation.

• Calcium ions play a very important role in clotting.

Lymph (Tissue fluid)

• As the blood passes through the capillaries in tissues, some water along with many small water-soluble substances move out into the spaces between the cells of tissues leaving the larger proteins and most of the formed elements in the blood vessels.

• This fluid released out is called the interstitial fluid or tissue fluid.

• It has the same mineral distribution as that in plasma.

• Exchange of nutrients, gases, etc., between the blood and the cells always occurs through this fluid.

• An elaborate network of vessels called the lymphatic system collects this fluid and drains it back to the major veins.

• The fluid present in the lymphatic system is called the lymph.

• Lymph is a colourless fluid containing specialised lymphocytes which are responsible for the immune responses of the body.

• Lymph is also an important carrier for nutrients, hormones, etc.

• Fats are absorbed through lymph in the lacteals present in the intestinal villi.

To be continued…