Albumin a. is a blood buffer. b. helps maintain blood’s osmotic pressure. c. distributes body heat. d. transports certain molecules.

Albumin

• it is one of the plasma proteins and it has a molecular weight 70000.
• it is the most abundant plasma protein and its amount average 4 gm%.
• it is produced in the liver.
• it has numerous functions in the body : examples : 1- it buffers PH ( = blood buffer ), plasma proteins ( as albumin ) act as weak acids combined with a base ( Na ) at the alkaline PH of blood ( 7.4 ) forming a buffer system ( = PH regulator ) composed of proteinic acid ( very weak ) and Na proteinate. if an acid is added to blood e.g. lactic acid during muscle exercise then : Na. proteinate + Lactic acid ------ Na. lactate ( Alkaline ) + proteinic acid.( very weak ). so, a very weak acid ( proteinic acid ) is formed instead of a relatively stronger one ( lactic acid ). 2- helps maintain blood osmotic pressure : - Albumin pass slightly through capillary so, it remain in high concentration in blood and do not leave it to tissue spaces, so, it create an effective osmotic pressure which tends to absorb fluid into blood against the filtering force of capillary blood pressure. 3- it acts as a carrier for transport of many substances. - it combines with certain important substances ( e.g. hormones, fatty acids ) and carry them as a large molecule to prevent their loss in urine.