TEAS Digestive

Gastrointestinal

The continuous long tube of the digestive system that extends from the mouth to the anus, responsible for processing food, absorbing nutrients, and eliminating waste.

Ingestion

The act of taking food, liquid, or other substances into the body by swallowing or consuming them.

Digestion

The breakdown of large, insoluble food molecules into small, water-soluble molecules mechanically and chemically so they can be absorbed into the blood.

Absorption

The process by which small nutrient molecules pass through the wall of the gastrointestinal tract into the blood or lymph.

Elimination

The expulsion of indigestible food residues and metabolic wastes from the body in the form of feces via the anus.

Mechanical digestion

The physical breakdown of food into smaller pieces through chewing, churning, and segmentation to increase surface area.

Chemical digestion

The enzymatic breakdown of complex food molecules (proteins, fats, carbohydrates) into their chemical building blocks.

Saliva

A watery fluid secreted by salivary glands in the mouth containing mucus, antibodies, and the enzyme amylase to begin digestion.

Epiglottis

A flexible flap of cartilage behind the tongue that covers the windpipe during swallowing to prevent food from entering the respiratory tract.

Bolus

A small, rounded mass of chewed food mixed with saliva ready to be swallowed.

Peristalsis

Rhythmic, wave-like muscular contractions of the gastrointestinal tract that push food forward through the digestive system.

Esophagus

A muscular tube connecting the throat (pharynx) to the stomach, transporting food via peristalsis.

Hydrochloric acid

A strong, corrosive acid secreted by parietal cells in the stomach that creates a low pH to kill pathogens and activate pepsin.

Pepsin

A major digestive enzyme secreted by chief cells in the stomach that begins the chemical breakdown of proteins into smaller peptides.

Chyme

The semifluid, pulpy mass of partially digested food and gastric juices produced in the stomach before entering the small intestine.

Stomach

A muscular, J-shaped sac that stores food, mixes it with digestive juices, and initiates protein digestion.

Lower esophageal sphincter

A ring of smooth muscle at the junction of the esophagus and stomach that prevents stomach acid from flowing backward.

Pyloric sphincter

A valve ring of smooth muscle that controls the flow of chyme from the stomach into the duodenum.

Small intestine

The long, coiled tubular organ where the majority of chemical digestion and nutrient absorption takes place.

Villi

Tiny, finger-like projections lining the inner surface of the small intestine that maximize surface area for nutrient absorption.

Duodenum

The first and shortest section of the small intestine where digestive enzymes from the pancreas and bile from the liver mix with chyme.

Jejunum

The middle section of the small intestine dedicated heavily to the absorption of nutrients and amino acids.

Ileum

The final section of the small intestine that absorbs remaining nutrients, vitamin B12, and bile salts before passing waste to the large intestine.

Mucosa

The innermost mucous membrane layer of the gastrointestinal tract responsible for secretion and absorption.

Submucosa

The layer of connective tissue beneath the mucosa containing blood vessels, lymphatic vessels, and nerve plexuses.

Muscularis

The thick layer of smooth muscle in the gastrointestinal wall (typically circular and longitudinal layers) responsible for peristalsis and segmentation.

Serosa

The outermost layer of the gastrointestinal tract composed of a thin layer of connective tissue and epithelium that reduces friction.

Lamina propria

A thin layer of loose connective tissue supporting the epithelium within the mucosal layer of the gut.

Chief cells

Specialized cells in the stomach glands that synthesize and secrete pepsinogen and gastric lipase.

Parietal cells

Specialized stomach epithelial cells that secrete hydrochloric acid and intrinsic factor for vitamin B12 absorption.

Bile

A fluid produced by the liver and stored in the gallbladder that emulsifies dietary fats to aid their digestion and absorption.

Large intestine

The terminal portion of the gastrointestinal tract comprising the cecum, colon, rectum, and anal canal, responsible for water absorption and waste compaction.

Ascending colon

The first major section of the large intestine that travels upward on the right side of the abdominal cavity.

Transverse colon

The middle, horizontal section of the large intestine that spans across the abdomen below the stomach and liver.

Descending colon

The section of the large intestine that travels downward on the left side of the abdominal cavity toward the pelvis.

Cecum

A pouch-like sac at the beginning of the large intestine where the appendix attaches.

Rectum

The final straight portion of the large intestine that stores feces temporarily before defecation.

Liver

A large metabolic organ that produces bile, processes nutrients, detoxifies chemicals, and regulates blood sugar.

Gallbladder

A small, pear-shaped organ situated beneath the liver that stores, concentrates, and releases bile into the small intestine.

Pancreas

A glandular organ that secretes digestive enzymes (exocrine) and vital hormones like insulin and glucagon (endocrine).

Alpha cells

Specialized cells in the pancreatic islets that secrete glucagon to raise blood glucose levels.

Beta cells

Specialized cells in the pancreatic islets that secrete insulin to lower blood glucose levels.

Acinar cells

The exocrine cells of the pancreas that synthesize and secrete digestive enzymes into pancreatic ducts.

Gastrin

A hormone secreted by stomach cells that stimulates gastric acid secretion and stomach motility.

Cholecystokinin

A hormone released by the small intestine that stimulates the release of bile from the gallbladder and digestive enzymes from the pancreas.

Secretin

A hormone released by the duodenum that stimulates the pancreas to secrete alkaline fluid to neutralize stomach acid.

Insulin

A hormone that lowers blood glucose levels by promoting cellular uptake of glucose and storage as glycogen.

Glucagon

A hormone that raises blood glucose levels by stimulating the breakdown of glycogen in the liver.