Human Physiology: Digestive System Vocabulary

Absorption

third step of digestion; villi in the small intestine increase surface area for nutrients to be absorbed into the bloodstream

Ascending Colon

first vertical segment of the large intestine; absorbs excess water and vitamins to concentrate feces

Bile

substance secreted into the duodenum by the liver and stored in the gall bladder; aids in digestion

Chemical Digestion

breakdown of food into smaller molecules using chemical energy and enzymes to break down food particles

Chyme

mass of food and digestive juices passing from the stomach into the small intestine

Descending Colon

final vertical segment of the large intestine; absorbs excess water and vitamins to concentrate feces

Duodenum

first segment of the small intestine; breaks down proteins, starches, and fats

Elimination

final step in digestion; waste is stored in the colon and released from the body through the rectum and anus

Feces

concentrated, solid food waste which is eliminated from the body

Gastrointestinal Tract

also called the GI tract, or alimentary canal; includes any organs directly connected from mouth to anus

Ileum

final segment of the small intestine, absorbs bile acids, water, and vitamin B-12

Ingestion

first step of digestion; food enters the GI tract through the mouth

Jejunum

second small intestine segment; absorbs carbs, fats, minerals, proteins and vitamins

Mastication

mechanical digestion of the mouth, also called chewing; act of using teeth to break down food particles so they can be swallowed

Mechanical Digestion

physically breaking down food which mostly occurs through mastication

Peristalsis

involuntary contraction and relaxation of GI muscles to move food through the digestive system

Propulsion

second step of digestion; food moves through the digestive tract beginning with swallowing

Saliva

enzyme-containing liquid secreted into the mouth to aid in digestion and begins the chemical digestion of food

Sphincter

muscles throughout the digestive system that prevent backflow into the esophagus (2)  and stomach (2)

Transverse Colon

second horizontal segment of the large intestine which absorbs excess water and vitamins to concentrate feces

Villi

finger-like projections in the small intestine to increase surface area and allow for maximum reabsorption of nutrients

secretion

works to lubricate, liquify, buffer digested food as it moves through the digestive

Mucosa

innermost layer with direct contact to food

Submucosa

contains blood vessels, lymphatic vessels and glands

Muscularis

smooth muscle to support movement through the digestive tract

Serosa/adventitia

the outer layer 

Liver

Helps emulsify lipids before they can be absorbed into the body, Is separated into a right lobe and left lobe

Gallbladder

Sends hormones signals when fat is detected in the small intestine which triggers the release of bile into the duodenum through the bile duct.

pancreatic juice

Mixture of water, salts, sodium, bicarbonate and digestive enzymes, released into the small intestine

Cecum

helps to absorb water and salt. It is attached to the appendix