Physiology of the Gastrointestinal Tract

This set of flashcards covers key terms and concepts related to the physiology of the gastrointestinal tract.

Gastrointestinal (GI) Tract

A tube-like structure that extends from the mouth to the anus and includes the esophagus, stomach, small intestines, and large intestines.

Accessory glands

Digestive glands including the liver, pancreas, and gallbladder that aid in digestion.

Motility

One of the five main functions of the GI tract, involving the movement of food through the digestive system.

Secretion

The process in the GI tract that involves the release of digestive juices and hormones.

Digestion

The breakdown of food into smaller molecules that can be absorbed by the body.

Absorption

The process by which nutrients, electrolytes, and water are taken up from the GI tract into the bloodstream.

Mucosa

The innermost layer of the GI tract, containing epithelial cells responsible for secretion and absorption.

Submucosa

The layer of the GI tract containing connective tissue, blood vessels, and nerves.

Myenteric plexus

A nerve plexus located between the inner circular and outer longitudinal muscle layers that helps regulate GI functions.

Enteric Nervous System (ENS)

A complex network of neurons that governs the functioning of the GI tract independently of the central nervous system.

Cholecystokinin (CCK)

An endocrine secretion that helps regulate digestion and appetite by stimulating the gallbladder.

Intrinsically controlled

Functions of the GI tract that are regulated internally through nerve plexuses and local reflexes.

Extrinsic control system

Regulatory mechanisms involving external nerves and hormones that affect GI tract functions.

Autocrine mechanism

A signaling mechanism where a cell secretes substances that act upon itself.

Vagus nerve

A major nerve in the parasympathetic nervous system that sends signals to and from the GI tract, influencing gut motility and secretion.

Aldosterone

A steroid hormone that stimulates sodium and water reabsorption in the GI tract, impacting fluid balance.

Enterocytes

Absorptive cells in the intestinal lining responsible for nutrient absorption.

Enterochromaffin cells

Cells in the GI tract that secrete substances important for regulating digestive functions.

Neurocrine mechanism

A signaling pathway where neurotransmitters affect nearby muscle cells and glands.

Paracrine mechanism

A signaling mechanism where secretions from cells diffuse to nearby target cells.