GASTRIC ACID or GASTRIC JUICE

GASTRIC ACID or GASTRIC JUICE

Gastric acid or Gastric Juice is a digestive fluid formed in the stomach and is composed of hydrochloric acid (HCl), potassium chloride (KCl), and sodium chloride (NaCl).

Parietal cell

Parietal cells in the stomach secrete roughly two liters of acid a day in the form of hydrochloric acid. Acid in the stomach functions to kill bacteria, and to aid digestion by solubilizing food. The acid is also important to establish the optimal pH (between 1.8-3.5) for the function of the digestive enzyme pepsin.

Parietal cells secrete acid in response to three types of stimuli

1. Histamine - stimulates H2 histamine receptors (most significant contribution).

2. Acetylcholine - from parasympathetic  activity via the vagus nerve and enteric nervous system, stimulating M3 receptors.

3. Gastrin - stimulating CCK2 receptors (least significant contribution, but also causes histamine secretion by local ECL cells)