Gastrointestinal Function and Regulation

Overview of Gastrointestinal Function & Regulation

• The primary function of the gastrointestinal tract is to absorb nutrients and water into the body.
• The meal mixes with secretions from the gastrointestinal tract and organs like the pancreas, gallbladder, and salivary glands.
• The gastrointestinal tract includes the mouth, esophagus, stomach, duodenum, jejunum, ileum, cecum, colon, rectum, and anus.

Gastrointestinal Secretions

Salivary Secretion

• Saliva is the first secretion encountered during digestion, produced by three pairs of salivary glands (parotid, submandibular, and sublingual glands).
• Saliva has organic constituents that initiate digestion (starch breakdown by amylase) and protect the oral cavity from bacteria (immunoglobulin A and lysozyme).
• Salivary secretions differ in proteinaceous and mucinous components based on the number of serous and mucous salivary acinar cells.
• Saliva is hypotonic and alkaline, neutralizing gastric secretions that reflux into the esophagus.
• Salivary secretion is controlled by neural influences, primarily the parasympathetic branch of the autonomic nervous system, with slight modifications by sympathetic input.
• Saliva facilitates swallowing, keeps the mouth moist, serves as a solvent for taste buds, aids speech, and keeps the mouth and teeth clean.

This quiz covers the primary function of the gastrointestinal tract, including the process of nutrient absorption and the role of various secretions and organs.