Medical Term - Module 8

Digestive System

digestive system

structures: anus, esophagus, gallbladder, large intestine, liver, mouth, oral cavity, pancreas, pharynx, salivary glands, small intestine, stomach

functions: breaks down food through mechanical and chemical digestion, and absorbs nutrient molecules into the body to enter into the bloodstream, and then eliminates solid waste

an/o

anus

append/o, appendic/o

appendix

bar/o

weight

bucc/o

cheek

cec/o

cecum

cholangi/o

bile duct

chol/e

bile, gall

cholecyst/o

gallbladder

choledoch/o

common bile duct

cirrh/o

yellow

col/o, colon/o

colon

dent/o, odont/o

tooth

diverticul/o

pouch

duoden/o

deuodenum

enter/o

small intestine

esophag/o

esophagus

gastr/o

stomach

gingiv/o

gums

gloss/o, lingu/o

tongue

hepat/o

liver

ile/o

ileum

jejun/o

jejunum

labi/o

lip

lapar/o

abdomen

lith/o

stone

or/o

mouth

palat/o

palate

pancreat/o

pancreas

pharyng/o

pharynx

polyp/o

polyp

proct/o

rectum and anus

pylor/o

pylorus

pyr/o

fire

rect/o

rectum

sialaden/o

salivary gland

sigmoid/o

sigmoid colon

-emesis

vomiting

-emetic

pertaining to vomiting

-iatric

pertaining to medical treatment

-istry

specialty of

-lithiasis

condition of stones

-orexia

appetite

-pepsia

digestion

-phagia

eat, swallow

-prandial

pertaining to a meal

-tripsy

surgical crushing

gut

a continuous muscular tube stretching from the mouth to the anus

• also called the alimentary canal or gastrointestinal tract

mastication

chewing movements of the mouth that break up food

deglutition

swallowing

uvula

hangs from the posterior edge of the soft palate, and plays a speech production and gag reflex

esophagus

a muscular tube that carries food through the thoracic cavity and diaphragm into the abdominal cavity, where it enters the stomach

• food is propelled along the esophagus by wavelike muscular contractions called peristalsis (pushes food through the entire gastrointestinal tract)

stomach

a J-shaped muscular organ that acts as a bag or sac to collect an churn food with digestive juices

• composed of three parts

  • fundus (upper region)

  • the body (main portion)

  • antrum (lower region)

• rugae: folds in the lining of the stomach

  • stretch out and disappear when the stomach is full

• chyme: semisoft mixture of food and digestive fluids that pass from stomach into small intestines

• muscular valves called sphincters control the entry and exit into the stomach

  • cardiac sphincter: keeps food from flowing backward into the esophagus

    • also called the lower esophageal sphincter or gastroesophageal sphincter

    • relaxes when throwing up or regurgitating

  • pyloric sphincter: tapers off from the antrum and regulates the passage of food into the small intestine

    • only a small amount of chyme is allowed to enter the small intestine with each opening of the sphincter because of size and acidity

small intestine

located between the pyloric sphincter and the colon, it is the major site of digestion and absorption of nutrients from food

• villi: finger-like projections from wall of small intestine; serve to increase surface area for nutrient absorption

  • microvilli: more projections covering each surface cell of a villus

• has three sections: duodenum, jejunum, and the ileum

large intestine

where fluid that remains after the complete digestion and absorption of nutrients in the small intestine goes

• most of this fluid is water that is reabsorbed, and the material that remains is solid waste called feces

• includes the

  • cecum: a pouch or sac-like area in the first two to three inches at the beginning of the colon

    • vermiform appendix: a small worm-shaped outgrowth at the end of the colon

  • colon: consists of four parts

    1. ascending colon: on the right side and extends from the cecum to the lower border of the liver

    2. transverse colon: moves horizontally across the upper abdomen toward the spleen

    3. descending colon: travels down the side of the body to where the sigmoid colon begins

    4. sigmoid colon: curves into an S-shape back to the midline of the body and ends at the rectum

  • rectum: where feces is stored, and leads into the anal canal

    • contains the anal sphincter the consists of rings of voluntary and involuntary muscles to control defecation

salivary glands

produces saliva that allows food to be swallowed with less danger of choking

• contains the digestive enzyme amylase that begins the digestion of carbohydrates

• three pairs of salivary glands:

  • parotid glands: in front of the ears

  • submandibular and sublingual glands: in the floor of the mouth

liver

process nutrients absorbed by intestines, detoxifies harmful substances in the body, and produces bile

• bile: important for the digestion of fats and lipids because it breaks up large fat globules into smaller droplets, making them easier to digest; called emulsification

gallbladder

stores bile produced by the liver

• travels through the hepatic duct and up the cystic duct to the gallbladder

• in response to the presence of fat in the chyme, the muscular wall of the gallbladder contracts and sends bile back down the cystic duct and into the common bile duct

  • common bile duct: carries bile to the duodenum where it is able to emulsify the fat in chyme

pancreas

connected to the duodenum by the pancreatic duct

• produces two important secretions for digestion:

  • buffers: neutralize acidic chyme that has just left the stomach

  • pancreatic enzymes: chemically digest carbohydrates, fats, and proteins

• also an endocrine gland that produces the hormones insulin and glucagon, which play a role in regulating the level of glucose in the blood