The Digestive System Structures Esophagus Stomach Small Intestine

The Digestive System

Structures • • Esophagus Stomach Small Intestine Large Intestine(colon or bowel) – Rectum – Anus • Liver • Pancreas • Gall Bladder

Function • To break down food into smaller portions that can be absorbed into the bloodstream and delivered to the cells of the body. • This process is called DIGESTION.

2 types of digestion: chemical and mechanical – Mechanical digestion mashes and grinds food into smaller pieces. • Stomach, teeth, tongue use mechanical digestion – Chemical digestion is the breaking down of food into molecules • Stomach, small intestine, and saliva use chemical digestion.

More on digestion • Begins in the mouth • Most occurs in the small intestine

The digestive tract Ø Food passes through the digestive tract Ø Includes the mouth, esophagus, stomach, small intestine, large intestine

Esophagus • Muscular tube that connects the pharynx (throat) to the stomach

Stomach • Muscular, sac like organ • Uses chemical and mechanical digestion to break down food • Contains acid and enzymes to break down food and kill bacteria you may swallow

Small Intestine • Smaller in diameter; longer in length • Most digestion occurs here • Lined with villi that increase surface area for nutrient absorption • Nutrients are absorbed in the bloodstream here

Large Intestine • Stores, compacts, and eliminates waste products • Fiber helps to keep the stool(poop) soft and moving through • Last part is the rectum – Stores feces(poop) until it can be eliminated from the body – Opening is called the anus

Liver • Not part of the DIGESTIVE TRACT aids in digestion • Makes bile • Stores and absorbs nutrients • Breaks down toxins

Gall Bladder • Not part of the DIGESTIVE TRACT aids in digestion • Stores bile that is made in the liver

Pancreas • Not part of the DIGESTIVE TRACT aids in digestion • Neutralizes stomach acids – The body’s natural antacid (like Tums) • Produces enzymes that aid in digestion • Also part of the endocrine system