The Digestive System - Lecture Notes

These flashcards cover key terms and concepts related to the digestive system based on the lecture notes.

Digestive System

A system that consists of the gastrointestinal tract and accessory organs, responsible for processing food and absorbing nutrients.

Gastrointestinal Tract (GI Tract)

The long tube composed of the mouth, esophagus, stomach, small intestine, large intestine, and anus where food is processed.

Accessory Digestive Organs

Teeth, tongue, salivary glands, liver, gallbladder, and pancreas that assist in digestion.

Ingestion

The act of taking food into the mouth.

Secretion

The release of digestive juices, including enzymes, acids, and buffers, into the lumen of the GI tract.

Mixing & Propulsion

Churning and movement of food through the gastrointestinal tract.

Digestion

The mechanical and chemical breakdown of food into smaller components.

Absorption

The passage of digested products from the GI tract into blood or lymph.

Defecation

The elimination of feces from the gastrointestinal tract.

Mucosa

The inner lining of the GI tract composed of epithelial tissue, connective tissue, and smooth muscle.

Submucosa

A layer of the GI tract containing connective tissue, blood vessels, and nerve fibers, often secreting buffers and enzymes.

Muscularis

The muscle layer of the GI tract responsible for peristalsis and segmentation.

Serosa

The outer layer of the GI tract covering and supporting the digestive organs.

Enteric Nervous System (ENS)

A component of the autonomic nervous system that governs the function of the gastrointestinal tract.

Esophageal Phase of Deglutition

The phase of swallowing that occurs once the bolus enters the esophagus and is pushed toward the stomach.

Gastric Juice

A mixture of digestive fluids secreted by the stomach lining, containing hydrochloric acid, pepsin, and intrinsic factor.

Chyme

The semi-liquid mixture of food, saliva, and gastric juices that forms in the stomach.

Pancreatic Juice

A fluid produced by the pancreas that contains digestive enzymes and bicarbonate for neutralizing stomach acid.

Bile

A digestive fluid produced by the liver, stored in the gallbladder, aiding in the emulsification of fats.

Absorptive Cells of the Small Intestine

Cells that absorb nutrients in the intestinal mucosa, containing microvilli that increase surface area.

Haustral Churning

A type of mixing movement in the large intestine, moving contents between haustra.

Mass Peristalsis

Powerful contractions in the large intestine that move contents toward the rectum.

Defecation Reflex

The reflex action involving contraction of rectal muscles and relaxation of anal sphincters for elimination of feces.

Hormonal Regulation of Digestion

The process by which hormones like gastrin, secretin, and CCK (cholecystokinin) regulate digestive activities.

Aging Effects on the Digestive System

Changes such as decreased secretory mechanisms, reduced motility, and altered sensory response.