Question

What do you mean by physiological buffers $ ? $ What are the different types of buffers found in the blood $ ? $ If possible, please state examples.

Answer 1

Hint :Here first understand what buffers. Then understand how it is obtained and what are physiological buffers. Then mention the different types of buffers present in the blood. Finally, give some examples.

Complete Step By Step Answer:
A buffer is a solution that resists changes in pH. buffers are physiologically very important. The three major buffer systems of our body are carbonic acid bicarbonate buffer system, phosphate buffer system and protein buffer system. A buffer must contain a weak acid and its conjugate base. Buffers can be made from weak acids or base and their salts. Buffers can be made by adding a strong acid or base to a weak acid or base.
 Physiological buffers are chemicals used by the body to prevent large changes in the pH of a bodily fluid. Physiological buffer system usually consists of a weak acid and its conjugate base.
 Human blood contains a buffer of carbonic acid ( $ {H_2}C{O_3} $ ) and bicarbonate anion ( $ HC{O_3}^ - $ ) in order to maintain blood pH between $ 7.35 $ and $ 7.45 $ , as a value higher than 7.8 or lower than 6.8 can lead to death. In this buffer, hydronium and bicarbonate anion are in equilibrium with carbonic acid. When any acidic substance enters the bloodstream, the bicarbonate ions neutralize the hydronium ions forming carbonic acid and water. Carbonic acid is already a component of the buffering system of blood. Thus, hydronium ions are removed, preventing the pH of blood from becoming acidic.
 A solution of acetic acid and sodium acetate ( $ C{H_3}COOH + C{H_3}COONa $ ) is an example of a buffer that consists of a weak acid and its salt. An example of a buffer that consists of a weak base and its salt is a solution of ammonia and ammonium chloride ( $ N{H_3} + N{H_4}Cl $ ).

Note :
Note that the buffer has a definite pH value that doesn't change on keeping for a long time and on dilution. Also, its pH value doesn't change even with the addition of a small amount of a strong acid or a base. Blood is an example of a natural buffer.