Digestive System Study Guide

Comprehensive vocabulary flashcards covering the organs, anatomy, enzymes, and functions of the digestive system.

Alimentary canal

A continuous coiled hollow tube that includes the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.

Ingestion

The process of taking in food or getting food into the mouth.

Digestion

The process of breaking down food both physically and chemically.

Absorption

The movement of nutrients into the bloodstream, primarily occurring in the small intestine.

Defecation

The process that rids the body of indigestible waste from the large intestine.

Accessory digestive organs

Organs including the teeth, salivary glands, pancreas, liver, and gallbladder that assist in digestion.

Uvula

A fleshy projection of the soft palate that hangs down in the back of the throat.

Vestibule

The specific anatomical term for the space between the lips or cheeks externally and the teeth and gums internally.

Frenulum

A small piece of tissue connecting two tissues, such as the tongue to the floor of the mouth or the lips to the gums.

Mastication

Another word for chewing.

Esophagus

A tube about 10 inches long that connects the pharynx to the stomach and must pass through the diaphragm muscle.

Peristalsis

Slow rhythmic squeezing of muscles for propelling food downwards through the digestive system.

Cardioesophageal sphincter

The sphincter connecting the esophagus to the stomach which prevents acid from backing up into the esophagus.

Rugae

Internal folds of the stomach mucosa that allow the stomach to stretch when needed and increase surface area.

Chyme

Processed food that is ready to be delivered from the stomach to the small intestine.

Simple columnar epithelium

The type of cell that makes up the mucosa of the stomach and secretes mucus to help line the digestive system.

Mucous neck cells

Cells in the stomach that produce a sticky alkaline mucus to protect the stomach wall from acid.

Gastric glands

Glands situated in gastric pits that secrete gastric juice.

Chief cells

Cells that produce protein-digesting enzymes known as pepsinogens.

Pepsinogen

The inactive form of the protein-digesting enzyme produced by chief cells.

Parietal cells

Cells in the gastric gland that produce hydrochloric acid ($HCl$).

Hydrochloric acid ($HCl$)

Substance that creates an acidic environment in the stomach and activates pepsinogen into pepsin.

Pepsin

The active protein-digesting enzyme formed when pepsinogen is activated by hydrochloric acid.

Enteroendocrine cells

Cells that produce gastrin, a hormone that regulates stomach activity.

Gastrin

A hormone produced by enteroendocrine cells that regulates the activity of the stomach.

Small intestine

The body’s major digestive organ, approximately 20 feet long, and the site of nutrient absorption into the blood.

Pyloric sphincter

The sphincter that controls the movement of food from the stomach into the small intestine.

Ileocecal valve

The entry point where the small intestine ends and the large intestine begins.

Mesentery

A structure that suspends the small intestine from the posterior abdominal wall to hold it in place while allowing movement.

Villi

Fingerlike structures formed by the mucosa that increase the surface area of the small intestine to absorb nutrients.

Microvilli

Tiny microscopic projections of the cell’s plasma membrane that create a brush border appearance to increase absorption.

Plicae circulares

Deep folds of the mucosa and submucosa, also known as circular folds, in the small intestine.

Large intestine

Organ that absorbs water to consolidate waste and is the site where resident bacteria digest remaining nutrients, produce some vitamin k and b

Resident bacteria

Organisms in the colon that digest remaining nutrients, release gases, and produce vitamins K and B.

Cecum

The saclike first part of the large intestine that absorbs fluid and salts to help form feces.

Appendix

A small tube-like structure attached to the cecum which is an accumulation of lymphatic tissue that can become inflamed.

Salivary glands

Glands including the parotid, submandibular, and sublingual that produce saliva for digestion and lubrication.

Parotid glands

The largest salivary glands, located near the ears, which produce enzyme-rich saliva to break down starches.

Submandibular glands

Glands found under the jaw bone that produce a watery and mucus-containing saliva.

Sublingual glands

Glands located under the tongue that produce mostly mucus-rich saliva to aid in swallowing.

Salivary amylase

An enzyme in the mouth that begins chemical digestion by breaking starch down into maltose.

Lipase

An enzyme that digests lipids (fats).

Liver

The largest gland in the body, located on the right side under the diaphragm, which produces bile.

Bile

A substance produced by the liver that emulsifies fats by physically breaking large fat globules into smaller ones.

Gallbladder

The organ that stores bile until it is needed in the small intestine.

Common hepatic duct

The duct that links the liver and gallbladder.

Deciduous teeth

Also known as baby teeth; a set of 20 teeth that are fully formed by age two.

Permanent teeth

The full set of adult teeth consisting of 32 teeth.

Incisors

Teeth classified for cutting.

Canines

Teeth classified for tearing or piercing.

Premolars

A classification of teeth used for grinding.

Molars

A classification of teeth used for grinding, similar to premolars.

Propulsion

The movement of foods forward from one region of the digestive system to another.

Segmentation

Localized mixing in the small intestine where materials are moved back and forth.

Mechanical digestion

Physical processes like mixing food with the tongue, churning in the stomach, and segmentation, preparing food for further digestion by enzymes

Chemical digestion

The use of enzymes to break food down into its chemical building blocks.

Pancreatic amylase

Enzyme that completes the digestion of starch in the small intestine.

Trypsin

An enzyme that breaks proteins down into smaller peptides.

Major nutrients

Nutrients needed in large amounts, including carbohydrates, lipids, proteins, and water.

Minor nutrients

Vitamins and minerals that are essential but required by the body in much smaller quantities.

Sucrace

An enzyme that digests carbohydrates.

Lactase

An enzyme listed for the digestion of carbohydrates and starch.

Vitamin C

Supports the immune system, helps heal wounds, and acts as an antioxidant; found in oranges and strawberries.

Vitamin D

Helps the body absorb calcium for strong bones and teeth; sourced from sunlight and fatty fish.

Vitamin A

Supports vision, immune function, and skin health; found in carrots and sweet potatoes.

Calcium

A mineral that builds and maintains strong bones and teeth; deficiency can lead to osteoporosis.

Iron

A mineral that helps carry oxygen in the blood; deficiency can lead to anemia.

Potassium

Supports muscle function and heart health; found in bananas and potatoes.

Amino acids

The building blocks of proteins.

Sugars

The building blocks of carbohydrates.

Fatty acids

The building blocks of lipids (fats).

Maltose

The specific substance starch is broken down into by the action of salivary amylase.

Pancreas

An accessory digestive organ that produces enzymes like pancreatic amylase for starch digestion.

Metabolism factors

Conditions affecting metabolic rate including age, gender, physical activity, and diet.

Gastric juice

The secretions produced by gastric glands in the stomach containing HCl and enzymes.

Functions of stomach

Temporary storage tank for food, Site of food breakdown, Chemical breakdown of protein begins, Delivers chyme (processed food) to the small intestine

Location of stomach

left side of the abdominal cavity

Developmental aspects of the digestive system

begins in fetus, matures as an infant, improves in childhood, stabilizes in adulthood, slows with aging

ileocecal sphincter

connects the small intestine to the large intestine