How is the pH of blood buffered and regulated by the respiratory system?

Question

How is the pH of blood buffered and regulated by the respiratory system?

Answer 1

It is regulated by the rate of respiration. Increasing respiration increases the rate of expelling CO2, and decreasing respiration decreases the rate of  expelling CO2.

According to this equation for CO2 in the blood:

CO2 + H20 <--> H2CO3 <--> H+ + HCO3-

expelling CO2 drives the equlibrium towards the left, reducing H+ in the blood thereby raising pH. Slowing down expelling of CO2 drive the equilibrium to the right (CO2 is a by product of cell metabolism remember) and there by increasing H+ concentration in the blood, lowering pH.

This is the main way your body regulates pH, another, SLOWER way is H+ and HCO3- uptake and excretion by the kidneys. The lungs do this in minutes.

Answer 2

Breathing removes CO2 that accumulates in the blood and makes it acidic.