From Textbook (Anatomy Medical Terminology) - Unit 9: The Digestive System

alimentary canal

Alternate name for the gastrointestinal system

digestive system

Alternate name for the gastrointestinal system. It is also known as the digestive tract.

gastrointestinal system

Body system that includes the salivary glands, oral cavity (teeth, gums, palate, and tongue), pharynx, esophagus, stomach, small and large intestines, rectum, anus, and the accesssory organs of the liver, gallbladder, and pancreas. Its function is to digest food, absorb nutrients into the blood, and remove undigested material from the body. It is also known as the gastrointestinal tract, digestive system or tract, and alimentary canal.

deglutition

Process of swallowing

gustatory cortex

Area of the brain that receives and interprets tastes from the tongue

mastication

Process of chewing. This is part of the process of mechanical digestion.

mucosa

Mucous membrane that lines the gastrointestinal system and produces thin mucus

oral cavity

Mouth. Hollow area that contains the hard palate, soft palate, uvula, tongue, gums, and teeth

palate

The hard bone and posterior soft tissues that form the roof of the mouth

pharynx

Throat. The passageway for both food and air

salivary glands

Three pairs of glands (parodid, sublingual, and submandibular) that secrete saliva into the mouth. Saliva is a watery substance that contains the digestive enzyme amylase.

tongue

Large muscle that fills the oral cavity and assists with eating and talking. It contains receptors for the sense of taste.

uvula

Fleshy hanging part of the soft palate. During swallowing, it initiates the gag reflex to prevent food from entering the pharynx before the epiglottis has sealed the opening to the larynx (voice box).

cardia

First part of the stomach just after the esophagus

chyme

Semisolid mixture of partially digested food, saliva, digestive enzymes, and fluids in the stomach and small intestine

esophagus

Flexible, muscular tube that moves food from the pharynx to the stomach

fundus

Rounded, top part of the stomach

lower esophageal sphincter (LES)

Muscular ring at the distal end of the esophagus. It keeps food in the stomach from going back into the esophagus.

peristalsis

Coordinated contractions of smooth muscle that propel food, chyme, or wastes and water through the gastrointestinal tract

pyloric sphincter

Muscular ring that closes to keep chyme in the stomach or opens to let chyme go into the duodenum

pylorus

Narrowed, last part of the stomach just before it joins the duodenum. It contains the pyloric sphincter.

rugae

Deep folds in the gastric mucosa that expand to accommodate food

stomach

Organ of digestion between the esophagus and the small intestine. Areas of the stomach: cardia, fundus, body, and pylorus. The stomach secretes hydrochloric acid, pepsinogen, gastrin (to digest food) and intrinsic factor (to aid in the absorption of vitamin B12).

anus

External opening of the rectum. The anal sphincter is under voluntary control.

appendix

Long, thin pouch on the exterior wall of the cecum. It does not play a role in digestion. It contains lymphatic tissue and is active in the body's immune response.

cecum

Short sac that is the first part of the large intestine. The appendix is attached to the cecum's external wall.

colon

Longest part of the large intestine. It consists of the ascending colon, transverse colon, descending colon, and S-shaped sigmoid colon.

duodenum

First part of the small intestine. It secretes the hormone cholecystokinin. Digestion takes place there, as well as some absorption of nutrients and water.

haustra

Pouches in the wall of the large intestine that expand to accommodate the bulk of undigested materials

ileum

Third part of the small intestine. It connects to the cecum of the large intestine. Some digestion takes place there. There is absorption of nutrients and water through the wall of the ileum into the blood.

jejunum

Second part of the small intestine. Digestion takes place there, as well as some absorption of nutrients and water through the intestinal wall into the blood.

large intestine

Organ of absorption between the small intestine and the anus. The large intestine includes the cecum, colon, rectum, and anus. It is also known as the large bowel.

lumen

Central, open area inside a tubular structure such as the esophagus, small intestine, and large intestine

rectum

Short, straight segment that is the last part of the large intestine. It follows the sigmoid colon and connects to the outside of the body.

small intestine

Organ of digestion and absorption between the stomach and the large intestine. The duodenum, jejunum, and ileum are the three parts of the small intestine. It is also known as the small bowel.

villi

Microscopic projections of the mucosa in the small intestine. They produce the digestive enzyme lactase that breaks down sugar in carbohydrates, starches, and milk. The large combined surface area of the villi maximizes absorption of nutrients into the blood.

abdominopelvic cavity

Continuous cavity within the abdomen and pelvis that contains the largest organs (viscera) of the gastrointestinal system

bile

Bitter-tasting, thick fluid produced by the liver and stored in the gallbladder. It is released into the duodenum to digest fatty foods. It contains the yellow pigment bilirubin and the green pigment biliverdin.

bile ducts

Bile produced by the liver flows through the hepatic ducts to the common hepatic duct. Then it goes into the common bile duct to the duodenum. When that duct is full, bile goes into the cystic duct and gallbladder. All of these ducts form the biliary tree, a branching structure.

celiac trunk

Part of the abdominal aorta where arteries branch off to take blood to the stomach, small intestine, liver, gallbladder, and pancreas

gallbladder

Teardrop-shaped, dark green sac posterior to the liver that stores and concentrates bile. Fatty chyme in the duodenum causes it to contract and release bile into the duodenum.

liver

Large, dark red-brown organ in the abdominal cavity. It contains hepatocytes that produce bile.

mesentery

Thick, fan-shaped sheet of peritoneum that supports the jejunum and ileum

omentum

Broad, fatty apron of peritoneum. It supports the stomach and protects the small intestine.

pancreas

Yellow, elongated, triangular organ located posterior to the stomach. It secretes amylase, lipase, and protein-digesting enzymes into the duodenum.

peritoneum

Double-layer serous membrane that lines the abdominopelvic cavity and surrounds each gastrointestinal organ. It secretes peritoneal fluid to fill the spaces between the organs.

absorption

Process by which digested nutrients move through villi of the small intestine and into the blood

amylase

Digestive enzyme in saliva that begins the digestion of carbohydrates in the mouth. It is also secreted by the pancreas to finish the digestion of carbohydrates in the small intestine.

cholecystokinin

Hormone secreted by the duodenum when it receives fatty chyme from the stomach. Cholecystokinin stimulates the gallbladder to release bile and the pancreas to secrete its digestive enzymes.

defecation

Process by which undigested materials and water are removed from the body as a bowel movement

digestion

Process of mechanically and chemically breaking down food into nutrients that can be used by the body

elimination

Process in which undigested materials and water are eliminated from the body in a solid form (feces)

emulsification

Process in which bile breaks down fat

enzymes

Substances that speed up chemical reactions in the body. During chemical digestion, enzymes break the chemical bonds in food molecules. Enzymes are produced by the salivary glands, stomach, small intestine, and pancreas. An enzyme name usually ends in -ase.

feces

Formed, solid waste composed of undigested material and water that is eliminated from the body. It is also known as stool.

flatus

Gas produced by bacteria in the large intestine

gastrin

Hormone produced by the stomach. It stimulates the release of hydrochloric acid and pepsinogen in the stomach.

hydrochloric acid

Strong acid produced by the stomach. It breaks down food, kills microorganisms in food, and converts pepsinogen to pepsin.

lactase

Digestive enzyme from villi in the small intestine. It breaks down lactose, the sugar in carbohydrates, starches, and milk.

lipase

Digestive enzyme secreted by the pancreas. It breaks down fat globules in the duodenum into fatty acids.

pepsin

Digestive enzyme in the stomach that breaks down protein foods into protein molecules

pepsinogen

Inactive substance produced by the stomach. It is converted by hydrochloric acid to the digestive enzyme pepsin.