1. Digestive System Objectives What are the nutrients that the body uses
What is the purpose of digestion
Organs of the Digestive System

2. Nutrients of the Body Carbohydrates – Provide energy for the body
Fiber – helps food move through your digestive tract
Starch – Complex carbohydrate
Sugar – Simple carbohydrate. It is the building block of all carbohydrates

3. Fats Provides energy for the body when carbohydrates are not available
Fatty acids and glycerol – building blocks of fats
Saturated – from animals mainly
Unsaturated – from plants mainly

4. Proteins
Provides energy for the body when fats and carbohydrates are not available.
Used to build and repair the body
Amino acids – building blocks of proteins

5. Minerals, Vitamins, Water
Minerals -- Helps your body function properly (ex. Keeps muscle, bones, nerves healthy)
Vitamins – needed for chemical reaction to occur in the body (ex. Aids in blood clotting)
Water – chemical reactions of the body take place in water.

6. Digestive System
Purpose of the digestive system is to fuel the body with energy from nutrients.
Types of Digestion
Mechanical – physical action of breaking food down into smaller pieces (done in mouth and stomach)
Chemical – food is broken down
into the essential nutrients the body can
use with the help of chemicals such as
enzymes

7. “Lock and Key” System = +
enzyme
carbohydrate
Sugars

8. “Lock and Key” System Enzymes Examples:
Chemicals that help bread down substances (foods)
Often end in “ase”
Examples:
Amylase  carbohydrates
Protease  proteins
Lipase  fats (lipids)

9. Mouth
Tongue
Esophagus
Liver
Stomach
Gall bladder
Pancreas
Large Intestine
Small Intestine
Rectum
Anus

10. Organs of the Digestive System
Mouth
Food is mechanically disgested with the help of the teeth and tongue
Food is chemically digested with the help of saliva and the enzyme amlyase
Saliva breaks down carbohydrates into sugars
Salivary glands – secretes saliva into the mouth
Food doesn’t enter the salivary glands
Chyme is the name of the chewed food in your mouth

11. Esophagus and Stomach
Esophagus – transports food to the stomach. Smooth muscles push food through the digestive tract, this is known as peristalsis
Stomach – produces gastric juice. A layer of mucus protects the stomach lining from gastic juice. Churns food with strong muscles
Gastric juice breaks down proteins into amino acids

12. Liver and Gall Bladder Liver – produces bile Gall Bladder – small sac
Bile chemically digests food in the small intestine.
Food doesn’t enter the liver
Bile breaks down fats into fatty acids
Gall Bladder – small sac
underneath the liver which
stores bile.

13. Pancreas Known as the “super gland”
Produces pancreatic juice. It chemically digests food in the small intestine
Food doesn’t enter the pancreas
Pancreatic juice breaks down carbohydrates, fats, and proteins

14. Small Intestine The most important digesting organ (22-24ft long)
Bile and pancreatic juice digest food in the small intestine
The small intestine produces intestinal juice
Intestinal juice breaks down carbohydrates and protein
Most nutrients digested are absorbed in the lining of the small intestine (villi)

15. Villi Fingerlike projections inside the small intestine
Increase the surface area for the absorption of nutrients
Absorption = mechanical digestion

16. Large Intestine Water is absorbed in the large intestine (3-4 ft long)
Waste products are collected in the large intestine (feces) and are stored in the rectum
Wastes are expelled from the body through the anus
No digestion occurs here