The Digestive System

Path of the Digestive System

· Mouth

· Esophagus

· Stomach

· Small Intestine

· Large Intestine

· Rectum

The Mouth

· Where digestion begins

· Two types digestion occur:

· Mechanical – breaking down of food into smaller pieces with teeth

· Chemical – the breaking down of complex molecules into simpler one by the enzymes in saliva

· An enzyme is a protein that speeds up chemical reactions.

The Esophagus

· A muscular tube that connects the mouth to the stomach

· Epiglottis – flap of tissue preventing food from entering trachea

· Peristalsis – involuntary muscular contractions that move food down the esophagus

The Stomach

· A J-shaped muscular pouch

· Holds about 2 liters of food

· Both mechanical and chemical digestion take place as stomach churns food in digestive juices.

· Contains enzyme Pepsin and Hydrochloric Acid

The Small Intestine

· Makes up about 2/3 of the digestive system.

· Where almost all chemical digestion and absorption of nutrients takes place.

· Contain millions of tiny finger-like structures called villi where the absorption takes place.

Other Digestive Organs

· Liver

· Heaviest organ of the body

· Produces bile to break down fat

· Gallbladder

· Holds bile until it is needed in the small intestine

· Pancreas

· Triangular shape

· Produces insulin to break down sugars

The Large Intestine

· Last section of the digestive system

· Water is absorbed, and remaining material readied for elimination from body.

· Last section is known as the rectum.

Pop Quiz

· 1) Where does digestion begin?

· 2) What type digestion takes place in the stomach?

· 3) What is the name of the finger-like structures that cover the interior of the small intestine?

· 4) What does the enzyme produced by the pancreas break down?

· 5) What is the name of the enzyme that brakes down sugar?