1. Digestive System Objectives: What are the nutrients that the body uses
What is the purpose of digestion
Identify the 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. Nutrients of the Body
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. Nutrients of the Body
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. Nutrients of the Body
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
Chemicals that help break down substances (foods)
Often end in “ase”
Examples:
Amylase  carbohydrates
Protease  proteins
Lipase  fats (lipids)

9. What’s missing?

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

11. Organs of the Digestive System
Esophagus
Stomach
transports food to the stomach (mechanical)
produces gastric juice to breakdown proteins into amino acids (chemical)
Smooth muscles push food through the digestive tract, this is known as peristalsis
A layer of mucus protects the stomach lining from gastric juice
Churns food with strong muscles (mechanical)

12. Organs of the Digestive System
Liver
Gall Bladder
produces bile that chemically digests food in the small intestine
small sac underneath the liver which stores bile - mechanical
Bile breaks down fats into fatty acids
Food doesn‘t enter the liver
Food doesn’t enter the liver

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

14. Organs of the Digestive System
Small Intestine
Villi
most important digestive organ (22-24ft long); absorption of nutrients through villi - mechanical
Fingerlike projections inside small intestine; increase the surface area for nutrient absorption
Bile and pancreatic juice digest food in the small intestine - chemical
Absorption = mechanical digestion
Intestinal juice breaks down carbohydrates and protein – chemical

15. Organs of the Digestive System
Large Intestine
Water is reabsorbed in the large intestine (3-4 ft. long) - mechanical
Waste products are collected in the large intestine (feces) and are stored in the rectum - mechanical
Wastes are expelled from the body through the anus - mechanical
No nutrients are absorbed in the large intestine