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