1. Digestive System

2. Digestive System Which organ of the digestive system does
Knife
Food Processor
Garbage Disposal
Which organ of the digestive system does
each picture represent?

3. Digestive System
The function of the digestive system is to break down food so that it can be used as energy in your body.
The system consists of a series of complex organs and glands (which excrete enzymes) that break down food into small usable particles.

4. Digestive System Mechanical Digestion:
-food is broken down mechanically, with movement
Ex: Teeth
Chemical Digestion:
-food is broken down with a chemical or enzyme
Ex: Saliva

5. Digestive System
Peristalsis- series of involuntary smooth muscle contractions along the walls of the digestive tract.
Moves food through the digestive system.

6. Digestive System Organs Involved: Mouth Esophagus (A) Stomach (C)
Small Intestine (E)
Large Intestine (F)
Appendix
Pancreas (D)
Liver (K)
Gall Bladder (J)

7. The mouth completes both mechanical and chemical digestion!
Digestive System
Digestion begins in the mouth.
As you chew your food, two processes are occurring:
TEETH- your teeth begin mechanical digestion by breaking down food into smaller pieces.
SALIVA- this enzyme helps break down starches chemically
The mouth completes both mechanical and chemical digestion! 1

8. Digestive System
As you swallow, the food must pass several structures:
Pharynx- Back of the throat opens into esophagus
Epiglottis- flap of tissue that keeps chewed food from going down the trachea to the lungs. As you swallow, the epiglottis flops closed.
Larynx- Vocal cords

9. Digestive System
The esophagus is a long tube that runs from the mouth to the stomach.
After being chewed and swallowed, the food ball (bolus) enters the esophagus. 2

10. 3 Digestive System The food is deposited in the Stomach.
The stomach is a large, sac-like organ made of muscle. 3

11. The stomach completes both mechanical and chemical digestion!
Digestive System
The stomach churns food AND bathes it in gastric juice (acidic).
Food remains in the stomach for 2-4 hours, turning into a thin liquid soup called chyme.
The stomach completes both mechanical and chemical digestion! 3

12. Digestive System
The liquid chyme is the transported to the small intestine.
SI is a narrow muscular tube about 6 meters long, lined with villi. 4

13. Digestive System
Don’t forget the Bacteria!
Bile and other enzymes are injected into the Small Intestine to further break down the food.
Is this mechanical or chemical digestion?
Food remains in the SI for 3-5 hours 4

14. 4 Digestive System Villi- finger-like extensions that absorb nutrients
Villus expand surface area of SI. 4

15. Blood vessels pick up nutrients from SI
Digestive System
The function of the SI is to absorb all usable nutrients.
The villi are covered with capillaries which pick up the nutrients for ALL cells in the body.
Blood vessels pick up nutrients from SI
What system works with Digestive? 4

16. Don’t forget the Bacteria!
Digestive System
Don’t forget the Bacteria!
Anything (liquid or solid) that is not absorbed by the SI is sent to the Large Intestine.
The colon absorbs most excess liquids. 5

17. 5 Digestive System After about 18-24 hours…
The END process- solid waste (feces) is stored in the rectum until it is excreted through the anus. 5

18. Digestive System The digestive system is also part of the
Excretory system!

19. Your meal’s entire journey through the Digestive System has taken between 24 and 33 hours.

20. Digestive System- Accessory Organs
Many organs play a role in the digestion of foods but never come in contact with food, we call these accessory organs.
Three such organs are:
Liver
Gall Bladder
Pancreas

21. Digestive System- Accessory Organs
Liver- large organ located above and in front of the stomach.
It filters toxins from the blood and makes bile (breaks down fats).

22. Digestive System- Accessory Organs
Gall Bladder- small, sac-like organ located near the SI.
It stores and releases bile into the small intestine.

23. Digestive System- Accessory Organs
Pancreas- an enzyme producing organ located below the stomach and above the intestines.
Enzymes from the pancreas aid in digestion of carbohydrates, fats and proteins in the small intestine.