Question

Hamburger’s phenomenon is
A) Movement of bicarbonate ions from plasma to RBC and chloride ions from RBC to plasma.
B) Movement of bicarbonate ions from RBC to plasma and chloride ions from plasma to RBC.
C) Diffusion of $CO_2$ into alveoli.
D) Carrying of $CO_2$ in blood.

Answer 1

Hamburger effect or chloride shift named after the scientist Hartog Jakob Hamburger, it is a process which takes place in the cardiovascular system and is responsible for the exchange of bicarbonate and chloride ions across the red blood cells membrane.

Complete Answer:
- 70% of $CO_2$ in the form of bicarbonates transported and reacted with water in the presence of carbonic anhydrase which is abundant in RBC to form carbonic acid.
- Carbonic acid ($H_{2}CO_3$) is a weak acid which upon partial dissociation gives hydrogen ion ($H^+$) and bicarbonate ($H_{2}CO_3$) which occurs in RBC only.
- This bicarbonate ion diffuses outside the RBC in plasma where it combines with sodium ions and forms Sodium bicarbonate.
- Loss of bicarbonate ions from RBC results in the positive charge inside them which is further balanced by diffusion or entry of chloride ($Cl^-$) ion from plasma into the RBC.
- This phenomenon of exchange of chloride ion ($Cl^-$) and bicarbonate ion ($H_{2}CO_3$) between plasma and RBC is known as chloride shift and hamburger phenomenon.

Hence the correct answer is option ‘B’.

Note: This phenomenon of chloride shift maintains the electrical neutrality of cells and the reverse of chloride shift occurs in tissues.