Your digestive system has three main functions

The Digestive System

• digestion

• absorption

• elimination

Mouth• Mastication: teeth tear,

crush, and grind your food. An enzyme in saliva begins to break down starches in your food.

• The pharynx is the junction between the digestive tract and the respiratory system.

• A flap of tissue called the epiglottis seals off the trachea, or windpipe, preventing food and liquid from entering your lungs.

• After passing through the pharynx, the food enters the esophagus, a muscular tube that connects the pharynx to the stomach

Esophagus

• Waves of muscle contractions, called peristalsis, push food through the rest of the digestive system.

Pharynx

Epiglottis

Mouth

Salivary gland

LiverEsophagus

Stomach

Pancreas

Small intestine

Large intestine

Rectum

Gallbladder

• From the esophagus, food passes through a valve and into the stomach, a muscular pouch located in the abdomen.

Stomach

• Mechanical digestion occurs as three layers of muscle produce a churning motion.

• Pepsin: breaks down the proteins• Hydrochloric acid: kills bacteria

• Peristalsis moves the food, which is now a thick liquid called chyme (kym), into the small intestine.

• The small intestine is where most chemical digestion and absorption of nutrients takes place. It’s about 22 feet long.

Small Intestine

• Liver The role of the liver is to produce bile. Bile is a substance that physically breaks up large fat droplets that clump together.

• Gallbladder Bile flows from the liver into the gallbladder, the organ that stores bile.

• Pancreas The pancreas secretes enzymes into the small intestine that complete the breakdown of carbohydrates, proteins, and fats.

• The lining of the small intestine is covered with millions of tiny fingerlike projections called villi.

                                                   

         

• The large intestine is about 5 feet long and 3 inches wide.

The Large Intestine

• As the material moves through the large intestine, most of the remaining water is absorbed into the blood.

• Collects waste from the small intestine and gets rid of it

Rectum• A short, muscular tube that

forms the lowest portion of the large intestine and connects it to the anus.

• Feces collects here until pressure on the rectal walls cause nerve impulses which send messages to the voluntary muscles in the anus to relax, permitting expulsion.

• Healthy eating habits and regular exercise are important for keeping your digestive system healthy.

Avoiding Digestive Disorders

• Consume plenty of fiber.

• Avoid fatty foods.

• Eat moderately.

• Plan meals for a time when you can relax.

• Drink water.

• Get regular exercise.