Nutrition Chapter 3

Umami

A brothy, meaty, savory flavor in some foods.

Lower Esophageal Sphincter

A circular muscle that constricts the opening of the esophagus to the stomach.

Phospholipid

A class of fat-related substances that contain phosphorus, fatty acids, and a nitrogen-containing component.

Enzyme

A compound that speeds the rate of a chemical process.

Peristalsis

A coordinated muscular contraction used to propel food down.

Anal Sphincters

A group of two sphincters that help control expulsion of feces from the body.

Insulin

A hormone produced by the pancreas. Increase the synthesis of glycogen in the liver and the movement of glucose in the bloodstream.

Bile

A liver secretion stored in the gallbladder and released through the bile duct into the small intestine. Essential for the digestion and absorption of fat.

Chyme

A mixture of stomach secretions and partially digested food.

Bolus

A moistened mass of food swallowed from the oral cavity into the pharynx.

Intrinsic Factor

A proteinlike compound produced by the stomach that enhances B-12 absorption.

Amylase

A starch-digesting enzyme produced by salivary glands and the pancreas.

Mucus

A thick fluid secreted by many cells. It acts as a lubricant and protection for cells.

Esophagus

A tube that connects the pharynx with the stomach.

Gallbladder

An organ attached to the underside of the liver; site of bile storage, concentration, and eventual secretion.

Absorptive Cells

Cells that line the villi. Participate in nutrient absorption.

Microvilli

Extensive folds on the mucosal surface of the absorptive cells.

Lipase

Fat-digesting enzyme produced the salivary glands, stomach, and pancreas.

Villi

Fingerlike protrusions in the small intestine that participate in digestion and absorption of food.

Duodenum

First section of the small intestine. Site of most chemical digestion of nutrients.

Anus

Last portion of the GI tract, an outlet for the digestive system.

Ileum

Last section of the small intestine.

Feces

Mass of water, fiber, tough connective tissues, bacterial cells, and sloughed intestinal cells that pass through the large intestine and out through the anus.

Jejunum

Middle section of the small intestine.

Digestion

Process by which large molecules are mechanically and chemically broken down to produce basic nutrients that can be absorbed.

Probiotic

Product that contains specific types of bacteria. Used to colonize the large intestine.

Protease

Protein-digesting enzyme produced by the stomach, small intestine, and pancreas.

Pyloric Sphincter

Ring of smooth muscle between stomach and small intestine.

Nutrigenomics

Study of how food impacts health through its interaction with our genes and its subsequent effect on gene expression.

Nutrigenetics

Study of the effects of genes on nutritional health

Prebiotic

Substance that stimulates bacterial growth in the large intestines.

Digestive System

System consisting of the GI tract and accessory structures. Performs mechanical and chemical processes of digestion, absorption of nutrients, and elimination of wastes.

Rectum

Terminal portion of the large intestine.

Motility

The ability to move spontaneously

Epiglottis

The flap that folds down over the trachea while swallowing.

Lumen

The hollow opening inside a tube.

GI Tract

The main sites in the body used for digestion and absorption of nutrients.

Ileocecal Sphincter

The ring of smooth muscle between the end of the small intestine and the large intestine.

Pharynx

The throat.

Saliva

Watery fluid, produced by the salivary glands in the mouth. Contains lubricants, enzymes, and other substances.