digestive system Flashcards
The digestive or gastrointestinal system performs four main functions:
ingestion
digestion
•absorption
•elimination
Ingestion
food material taken into mouth
Digestion
food is broken down, mechanically and chemically, as it travels through the gastrointestinal tract.
Digestive enzymes aid the breakdown of complex nutrients.
- Proteins → amino acids
- Sugars → glucose
- Fats → fatty acids or triglycerides
Absorption
Digested food passes into the bloodstream through lining cells of the small intestine.
•Nutrients travel to all cells of the body.
•Cells burn nutrients to release the energy stored in food.
Elimination
- The body eliminates solid waste materials that cannot be absorbed into bloodstream.
- The large intestine concentrates feces.
- The wastes pass out of the body through the anus.
Organs of the Digestive System
The gastrointestinal tract begins with the oral cavity.
Besides producing bile, the liver:
- Helps maintain normal blood glucose levels •Manufactures blood proteins necessary for clotting •Releases bilirubin, a pigment in bile
- Removes toxins and poisons from the blood
What happens if bilirubin cannot leave the body and remains in the bloodstream?
Hyperbilirubinemia
Function of the pancreas
Endocrine function: insulin in bloodstream cell
Exocrine function: enzymes in duodenum for digestion
Which term is the first part of the large intestine?
Cecum
Which term means swallowing?
Deglutition
absorption
Passage of materials through the walls of the small intestine into the bloodstream
amino acids
Small building blocks of proteins; released when proteins are digested
amylase
Enzyme secreted by the pancreas and salivary glands to digest starch
anus
Terminal end or opening of the digestive tract to the outside of body
appendix
Blind pouch hanging from the cecum
bile
Digestive juice made in the liver and stored in the gallbladder; breaks up large fat globules; composed of bile pigments, cholesterol, and bile salts
bilirubin
Pigment released by the liver in bile
bowel
Intestine
canine teeth
Pointed, dog-like teeth next to the incisors; also called cuspids or eyeteeth
cecum
First part of the large intestine
colon
Consists of the ascending, transverse, descending, and sigmoid segments
common bile duct
Carries bile from the liver and gallbladder to the duodenum; also called the choledochus
defecation
Elimination of feces from the digestive tract through the anus
deglutition
Swallowing
dentin
Primary material found in teeth; covered by the enamel in the crown and a protective layer of cementum in the root
duodenum
First part of the small intestine; measures 12 inches long
elimination
Act of removal of materials from the body
emulsification
Physical process of breaking up large fat globules into smaller globules
enamel
Hard, outermost layer of a tooth
enzyme
Chemical that speeds up reactions between substances; enzyme names end in –ase
esophagus
Tube connecting the throat to the stomach
fatty acids
Substances produced when fats are digested; a category of lipids
feces
Solid wastes; stool
gallbladder
Small sac under the liver; stores bile
glucose
Simple sugar
glycogen
Starch; glucose is stored in the form of glycogen in liver cells
hydrochloric acid
Substance produced in the stomach; necessary for digestion of food
ileum
Third part of the small intestine
incisor
One of four front teeth in the dental arch
insulin
Hormone produced by endocrine cells of the pancreas; transports sugar from the blood into cells and stimulates glycogen formation by the liver
jejunum
Second part of the small intestine
lipase
Pancreatic enzyme needed to digest fats
liver
Large organ located in the RUQ of the abdomen; secretes bile; stores sugar, iron, and vitamins; produces blood proteins; destroys worn-out RBCs; filters out toxins; normal adult liver weighs about 2 ½ to 3 pounds