Ch 15 The Digestive System

Digestive system

The group of organs that changes food into a form that can be used by the body’s cells

Digestion

The activity by which food is broken down and converted into an absorbable form.

Sources of manufactured energy

Carbohydrates, proteins, fats, minerals, water, and vitamins.

Mouth's accessory organs

Teeth, tongue, salivary glands, and saliva (which begin the process of digestion).

Ptyalin

An enzyme in saliva that begins the chemical breakdown of food and works with moisture to turn mashed food into a bolus.

Peristalsis

The involuntary, wave-like muscle contractions that move the bolus through the esophagus and into the stomach.

Epiglottis

The structure that closes during swallowing to direct the food bolus into the esophagus instead of the airway.

Stomach sphincters

The cardiac sphincter (at the esophageal end) and the pyloric sphincter (at the duodenal end).

Chyme

The semi-fluid mixture of food, mucus, hydrochloric acid, and enzymes formed in the stomach.

Three sections of the small intestine

Duodenum, jejunum, and ileum.

Liver and gallbladder digestive function

They contribute to digestion by adding bile to the chyme.

Gallbladder function

Concentrates and stores bile, releasing it into the duodenum via the cystic duct during digestion.

Common bile duct formation

Formed by the union of the cystic duct (from the gallbladder) and the hepatic duct (from the liver).

Cholelithiasis

The medical term for gallstones, which can cause jaundice if they block the cystic or common bile duct.

Laparoscopic cholecystectomy

The surgical procedure used to remove the gallbladder and gallstones.

Pancreas functions

Acts as both an exocrine gland (producing digestive enzymes and juices) and an endocrine gland (secreting insulin).

Intestinal villi

Tiny, finger-like projections in the small intestine that absorb nutrients from digestive material.

Large intestine functions

Eliminates waste products and non-digestible material, and absorbs water, salts, and protein from chyme.

Appendix location

Attached to the cecum section of the large intestine.

Three main colon sections

Ascending, transverse, and descending sections.

Terminal sections of the colon

Sigmoid colon, rectum, and anal canal.

Common GI diagnostic exams

Colonoscopy, barium swallow, upper/lower GI series, gastroscopy, nuclear medicine studies, occult blood test, proctoscopy, and sigmoidoscopy.