AIIMS SPECIAL IMAGE BASED QUIZ -4

 Regulation of Acid Base

Acid Base Balance is regulated by 3 Mechanisms.

1. Chemical Regulation - By Buffers

2. Physiological Regulation - 

A. By Lungs (Respiratory Mechanism)

B. By Kidneys (Renal Mechanism)

3. K+ Exchange

1. Chemical Regulation - 

Chemical Regulation is done by Buffers. These Buffers regulate the pH by accepting H+ or OH-.

Following are some types of Buffers 

A. Bicarbonate and Carbonic Acid- 

In Acidosis - H+ + HCO3- = H2CO3

In Alkalosis - OH- + H2CO3 = H2O + HCO3-

B. Phosphate Buffer -

In Acidosis - H+ + HPO4- = H2PO4

In Alkalosis - OH- + H2PO4 = H2O + HPO4-

C. Plasma Proteins (Albumin)-

R-CH-NH2-COO-  +   H+  =   R-CH-NH2-COOH

R-CH-NH2-COOH  +   OH-  = H2O  +   R-CH-NH2-COOH

But affinity of Calcium is Higher to Albumin In Comparison of OH- , so in Alkalosis there will be Hypocalcemia.

D. Haemoglobin - 

Haemoglobin regulates pH by 2 processes i.e.

(1) Chloride Shift (Hamburger Phenomenon)

(2) REverse Chloride Shift

2. Physiological Regulation - 

A. Respiratory Mechanism -

In Acidosis Respiratory Rate and DEPTH Increases to excrete more Co2 From the body, this is known as Hyperventilation.

In Alkalosis Respiratory Rate and DEPTH decreases to retain more Co2 in the body, this is known as Hypoventilation.

This type of compensation is Very Rapid. it lasts for Short Periods.

B. Renal Mechanism-

In Acidosis H+ is excreted in Urine.

In Alkalosis HCO3- is secreted and combines with Na+ to form NaHCO3, and is excreted by urine.

This type of compensation is Very Slow. it lasts for Long Periods.

3. Potassium Exchange -

In Acidosis there is excess of H+ ions in the blood, so to compensate this , K+ which is present in the cell comes out to Blood and H+ moves out to Cell, so it decreases the amount of H+ ions present in the Blood. Thus regulates the pH.

In Alkalosis there is lack  of H+ ions in the blood, so to compensate this , H+ which is present in the cell comes out to Blood and K+ moves out to Cell from the Blood, so it increases the amount of H+ ions present in the Blood. Thus regulates the pH.

So In Acid Base Imbalance K+ level shoul be closely monitored.