Question

In humans, how do you think buffers in the blood differ from buffers in the stomach.

Answer 1

In Human the pH of blood is 7.35-7.45 but in case of stomach the resting pH is 4-5. This pH is maintained by a buffer system in human body.

In case of blood:The buffer system in blood plays role to maintain pH in a almost neutral position(7.35-7.45), Higher or lower this pH value of blood can lead to death. When the acidity of the blood rises the HCO^3- ion neutralizes that acid and form H₂CO₃ that will dissociates into H₂O and CO₂.

H₃O⁺ + HCO⁻³ ⇌H₂CO₃+H₂O

H₂CO₃ ⇌ H₂O+CO₂

In case of Stomach: In the stomach the acidity is maintained in gastric lumen, but in the mucous layer this bi-carbonate buffer neutralizes the acid and protect the mucous layer. So in the stomach this bi-carbonate buffer is present for the protection of the mucous layer of stomach. not for the maintaining the pH of the stomach.