Pancreatic Secretions: Enzymes And Hormonal Regulation

Pancreatic Secretions: Enzymes And Hormonal Regulation

Name phase of gastric secretion and describe in detail. (or) Phases of gastric secretion.
Answer:

Phases of gastric secretion:

1. Cephalic phase:

• Secretion of gastric juice by the stimuli arising from head region is called cephalic phase.
• It occurs even before food enters the stomach.

Gastric Juice secreted:

• Gastric juice secreted during this phase is rich in enzymes and hydrochloric acid.
• 30-50% juice is secreted.

Regulation:

• This phase is regulated by two reflexes.

1. Unconditioned reflex:

Conditioned reflex.

It is stimulation of gastric juice via vagus nerve in response to sight, smell, thought or taste of the food.

2. Gastric phase:

• Once the food enters the stomach, the secretion of gastric juice increases, this is called gastric phase.

Gastric juice secreted:

• Gastric juice secreted during this phase is rich in pepsinogen and hydrochloric acid.
• 50-60% of the total juice is secreted during this phase.

Regulation:

• This phase is regulated by both nervous and hormonal mechanism.

3. Intestinal phase:

• This phase occurs when food enters the duodenum.

Regulation:

1. Initial phase.
   • As the food enters the intestine, it stimulates the duodenal mucosa to release gastrin.
   • This gastrin is transported to stomach where it stimulates the secretory activity of gastric glands.
2. Later stage.
   • After the initial increase in secretion of gastric juice, there is decrease or complete stoppage of secretion of gastric juice.
   • This secretion is inhibited by.
     • Enterogastric reflex.
     • GI hormone.