FUNCTIONS OF BLOOD

Red Blood Cells

Functions of Blood:

Blood is the medium in which dissolved nutrients, gases, hormones and wastes are transported through the body. Plasma and Cell-like bodies i.e. red blood cells, white blood cells and platelets are the main components of the blood. Like other organs and tissues, blood also performs specific functions. The overall functions of blood in humans are as follows:

Maintain Osmotic Pressure:

The plasma proteins maintain colloid osmotic pressure (also called Oncotic pressure, is a form of osmotic pressure which is exerted by proteins, especially Albumin in blood vessel’s plasma) of the blood (75% by albumins, 25% by globulins and almost none by fibrinogen). 

Transport of Materials:

As the definition of blood reflects that it transports gases, nutrients, hormones, wastes, etc in dissolved form throughout the body. Nutrients, water, salts and waste products are mainly transported by blood in body.

Transport of Hormones and Gases: 

All hormones are transported by blood from the endocrine tissues to the larger cells. Gases like O₂ and CO₂ are transported by blood. Blood carry the oxygen from the lungs, and transport it to oxygen deficient areas.

Immunity and Defense against Diseases:

Blood helps our body to defend against diseases. The Neutrophils and Monocytes engulf and destroy invading microorganisms e.g. bacteria. Blood provides immunity by the lymphocytes.

Production of Interferon and Antitoxins:

Blood produces interferon (a protein released, usually in response to the entry of a virus that has the property of inhibiting virus replication) and antitoxins which are proteins and protect our body from nucleic acids and toxins of invading organism.

Maintain Acid-Base Balance:

Blood acts as a buffer (a solution that resists the change in pH when alkali or acid is added) to maintain the acid — base balance by keeping the concentration of H⁺ and OH^- ions of the body in equilibrium.

Maintain Temperature and Homeostasis:

Blood helps the body in maintaining the internal environment, by producing, heparin (a compound occurring in the liver that inhibits blood coagulation) and also maintaining the amounts of chemicals (water, salts etc.) in the body thus maintaining temperature to a constant or nearly constant level. Thus blood helps in homeostasis and in maintaining the body temperature.

Exchange of Materials:

Blood helps in the exchange of materials between blood and body tissue through blood capillaries via interstitial cells.

Blood Clotting:

As the blood have a small colorless disk-shaped cell fragment without a nucleus, called as platelets which helps in blood clotting process and seals the wounds that stop entry of pathogens into body.