30.3 The Digestive System
What are the functions of the digestive system?
Its converts food into small molecules that can be used by the cells of the body. Food is processed by the digestive system in four places-ingestion, digestion, absorption, and elimination.
Stomach
a large muscular sac that continues the chemical and mechanical digestion of food
Parts of the Colon?
ascending, transverse, descending, sigmoid
Pepsin
enzyme that breaks down proteins into smaller polypeptide fragments
Villus
fingerlike projection in the small intestine that aids in the absorption of nutrient molecules (for surface area)
Pancreas
it produces enzymes that break down carbohydrates, proteins, lipids, and nucleic acids. it makes sodium bicarbonate (neutralizes stomach acid in duodenum). Pancreatic fluid and sodium bicarbonate for digestion.
Ileum
last region of the small intestine
Pyloric Valve
located bw the stomach and small intestine, opens to let chime into small intestine
Saliva
made of water, mucus, amylase
Jejunum
middle region of the small intestine
Chyme
mixture of enzymes and partially-digested food
Chemical Digestion
process by which enzymes break down food into small molecules that the body can use
Gallbladder
stores and concentrates bile
Liver
stores glycogen, breaks down toxins, and secretes bile to break down fat globules
Lymph Vessels
take in fats and fatty acids
Capillaries
take in nutrients in the small intestine
Duodenum
the first part of the small intestine and where almost all of the digestive enzymes enter the intestine
Bolus
the mashed up clump of food in the mouth before swallowing
Mechanical Digestion
the physical breakdown of large pieces of food into smaller pieces
Ingestion
the process of putting food into your mouth (opening to the digestive tract)
Gastrointestinal Tract
the tube in the body that goes all the way through
Esophagus
tube connecting the mouth to the stomach
Anal Sphincter
your butthole. teehee.
Large Intestine
(colon) organ in the digestive system that removes water from the undigested material that passes through it
Teeth
-incisors, cuspids, and bicuspids cut and tear food -molars grind and crush food into a fine paste that can be swallowed -tongue moves food around so it can come in contact with the teeth
Gastric Pits
-mucus line the stomach -digestive enzymes lower pH levels -HCl- pH turns pepsinogen into pepsin
Appendix
a small saclike organ that is between the small and large intestine
Peptic Ulcer
a sore in the stomach that is caused when the mucus layer fails and acids erode the stomach lining
Cardiac Sphincter
a thick ring of muscle that closes the esophagus after the bolus enters the stomach
Amylase
an enzyme that breaks down the chemical bonds in starches
Lysozyme
an enzyme that fights infection by digesting the cell walls of many bacteria that may enter the mouth with food
Peristalsis
the contractions of smooth muscles that provide the force that moves food through the esophagus toward the stomach