(i) The plasma proteins maintain colloid osmotic pressure of theblood(75% by albumins, 25% by globulins and almost none byfibrinogen).
(ii) Blood helps to trasport materials,in the body includingnutrients,water,salts and waste products. All hormones are trasportedby blood from the endocrine tissues to the target cells.
(iii) Gases O2 and CO2 are trasported by blood.
(iv) Blood helps in body defences against disease, neutrophils and
monocytes engulf and destroy invading microorganisms e.g. bacteria.
(v) Blood provides immunity by the lymphocytes.
(vi) Blood produces interferon and antitoxins which are proteins,and
protects our body from nucleic acids and toxins of invading organisms
(vii) Blood acts as a buffer to maintain the acid-base balance i.e.
concentration of H+ and OH- ions of the body.
(viii) Blood helps in maintaining the body temperature,
concentration of water and salts,thus helps in homoestosis.
(ix) Wall of Blood helps in the exchange of materials between blood
and body tissue through blood capillaries via interstitial fluid.
(x) Blood helps the body in maintaing the internal environment,by
producing heparin, histamines and also maintaing the amounts of
chemicals including water and salts in the body and body temperature
to a constant or nearly constant levels.
(xi) Blood helps in blood clotting process and seals the wounds,
that stop entry of pathogens into body.