The Digestive System

You are what you eat!

What is the function of the digestive system?

• The digestive system has three main functions:1. It breaks down food into molecules the body can use.

2. The digested molecules are absorbed into the blood.

3. Wastes are eliminated from the body.

Important definitions

• Digestion: the process by which your body breaks down food into small nutrient molecules (protein, fat, carbohydrates, vitamins, and minerals).

• Absorption: the process by which the nutrient molecules pass through the walls of your digestive system into your blood.

What are the major parts of the digestive system and their function?

• Mouth: Digestion begins in the mouth. Two types of digestion take place in the

mouth:1. Mechanical: this is done with

your teeth, breaking the food apart.

2. Chemical: the saliva in your mouth starts to breakdown starches (complex sugars).

Major parts and their function

• Esophagus: a muscular tube that connects the mouth and the stomach. Contraction of smooth muscles (peristalsis) pushes the food toward the stomach.

• Epiglottis: a small flap of tissue that seals off the windpipe to prevent food from entering the lungs.

Major parts and their function

• Stomach: mechanical and chemical digestion occurs here. The stomach squeezes (churns) the food, mixing it with fluids. It also releases enzymes to breakdown protein.

• Once the food is turned into liquid form, it is ready for final digestion and absorption.

Major parts and their function

• Small intestine: this is where most of chemical digestion takes place. It mixes with enzymes and secretions produced in three different organs.

• Liver: has many functions, but in digestion the liver produces bile, a substance that breaks down fat.

Major parts and their function

• Gallbladder: an organ that stores bile. After eating, bile passes from here through a tube to the small intestine.

• Pancreas: has many functions, but in digestion produces enzymes that breakdown fats, proteins, and starches.

These enzymes pass through a tube to the small intestine.

Major parts and their function

• Large intestine: the last section of the digestive system. The material entering here has water and undigested food (fiber). Water is absorbed and the remaining material passes through the rectum to the anus and out of the body.

http://videos.howstuffworks.com/discovery/28649-assignment-discovery-breaking-down-digestion-video.htm

What organs, in order, does the food pass through during the digestive process?

• Mouth

• Esophagus

• Stomach

• Small intestine

• Large intestine

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http://videos.howstuffworks.com/hsw/17328-the-digestive-system-understanding-digestion-video.htm

What other systems work with the digestive system?

• Circulatory: nutrient molecules are absorbed by the blood and carried throughout the body.

• Excretory: collects waste from digestion and eliminates it from the body.

• Endocrine: the pancreas releases enzymes during digestion.

The Digestive System

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