Cephalic phase

Definition

The cephalic phase is the initial stage of digestion that begins when sensory stimuli such as sight, smell, or thought of food trigger neural responses. These responses prepare the digestive system for food intake by activating salivary glands and gastric secretions.

5 Must Know Facts For Your Next Test

1. The cephalic phase activates the parasympathetic nervous system via the vagus nerve.
2. This phase accounts for about 20% of gastric secretions before food enters the stomach.
3. Sensory inputs like smell, sight, and taste stimulate this phase.
4. Gastrin and acetylcholine are key neurotransmitters involved in this process.
5. It prepares the gastrointestinal tract for efficient digestion and absorption.

Review Questions

Related terms

Gastric Phase: The second stage of digestion where food in the stomach stimulates further gastric secretions.

Intestinal Phase: The final stage of digestion that occurs when chyme enters the small intestine, regulating further digestive activity.

Vagus Nerve:

A cranial nerve that controls parasympathetic functions, including those in the cephalic phase.