Question

pH of gastric juice is
A. 2
B. 4
C. 6
D. 8

Answer 1

Hint: It is a scale to measure the number of hydrogen ions present in a solution and helps to detect whether a solution is acidic or basic.

Complete answer:
Gastric juice or stomach acid is a digestive fluid formed within the stomach lining. It is acidic because the protein-digesting enzymes of the stomach such as pepsin do not work well in the basic medium so the pH is maintained between 1.5 – 3.5 in the stomach. So, the pH is normally around 2.

Additional information
> Gastric juice composed of hydrochloric acid, potassium chloride, and sodium chloride.
> It helps in the digestion of proteins by activating digestive enzymes, which breaks the long chains of amino acids of proteins.
> Gastric juice is secreted by the oxyntic or parietal cells of the stomach.
> Gastric acid is regulated by both the autonomous nervous system and several hormones.
> The parasympathetic nervous system, via the vagus nerve, and the hormone gastrin stimulate the parietal cell to produce gastric acid.
> The production of gastric acid in the stomach is tightly regulated by positive regulators and negative feedback mechanisms.

So, the correct answer is 2.

Note: The role of gastric acid in the digestion was established in the 1820s and 1830s by William Beaumont on Alexis St. Martin, who as a result of an accident, had a hole in his stomach, which allowed Beaumont to observe the process of digestion and to extract gastric acid, verifying that acid played a crucial role in digestion.