Question

Which phase of gastric secretion is correctly matched with its description?

Group of answer choices

gastric phase — provides about 2/3 of the gastric juice released

cephalic phase — vagus nerve sends action potentials to the stomach

gastric phase — begins when food moves through the gastroesophageal sphincter

intestinal phase — cholecystokinin stimulates secretion of the gastric glands

Answer 1

The correct pair is (b) cephalic phase- vagus nerve sends action potential to the stomach.

There are three phases of gastric acid secretion. These are cephalic phase, gastric phase, and intestinal phase.

The following table shows the features of the three phases.

FEATURES	CEPHALIC PHASE	GASTRIC PHASE	INTESTINAL PHASE
Occurrence of the phase	Occurs before the food enters the stomach due to smell, sight, etc ( psychic stimulation)	This occurs when food is present in the stomach.	Occurs when the food is duodenum
Influences	Mainly secreted because of vagus nerve action. Sight and smell of food stimulates the medulla oblongata. This directs the vagus nerve to send more and more action potentials to the enteric plexuses. Hence gastric acid is released.	Local reflexes and response to gastrin. Here mechanoreceptors play a major role by detecting the stretch stimuli of the stomach due to food.	Chemoreceptors and hormonal feedback.
Amount	30-50%	50-60%	very less

Other statements are wrong because

• (a) In the gastric phase, Almost 50 to 60 % of gastric acid is secreted and not 2/3rd of total secretion.
• (b) gastric acid is secreted when food is present in the stomach due to stretch reflex.
• (d) Cholecystokinin actually reduces the secretion of gastric acid. In increases the secretion of pancreatic juices and bile.