What are the functions of the different types of plasma proteins?

Plasma proteins perform various functions including clotting, defence, transport, and maintaining osmotic balance.

Plasma proteins, which make up about 7% of the plasma, are primarily produced in the liver and play a crucial role in various physiological processes. They are categorised into three main types: albumins, globulins, and fibrinogen.

Albumins, the most abundant plasma proteins, are responsible for maintaining the osmotic balance between the blood and the tissues. They help to control the movement of water through the blood vessels, preventing excessive loss of fluid from the blood into the tissues. This is crucial in maintaining blood volume and blood pressure. Albumins also serve as transport proteins, carrying various substances such as hormones, drugs, and fatty acids that are insoluble in water.

Globulins are the second most abundant group of plasma proteins and are further divided into alpha, beta, and gamma globulins. Alpha and beta globulins transport lipids and fat-soluble vitamins, and also play a role in immune response. Gamma globulins, also known as immunoglobulins or antibodies, are produced by the immune system's B cells. They are crucial in the body's defence against pathogens, binding to antigens on the surface of foreign substances, marking them for destruction by the immune system.

Fibrinogen, although less abundant, plays a vital role in blood clotting. When a blood vessel is damaged, fibrinogen is converted into fibrin, a fibrous protein that forms a meshwork at the site of injury. This meshwork traps red blood cells and platelets, forming a clot that prevents further blood loss.

In addition to these, there are also other plasma proteins such as enzymes and hormones. Enzymes catalyse various biochemical reactions in the body, while hormones regulate a wide range of physiological processes. The functions of plasma proteins are thus diverse and essential for the body's normal functioning.