1. Digestive System

2. What is digestion?
Body breaks down food into small nutrient molecules

3. Where does digestion begin?
Mouth

4. What two types of digestion occur in the mouth?
1. Mechanical Digestion
Physically breaking down the food.
Chewing
Churning

5. What two types of digestion occur in the mouth?
2. Chemical Digestion
The salivary gland creates our saliva to soften the food so that it is easier to swallow.
Enzymes begin to break down the food into bolus.

6. Salivary Enzymes What are enzymes? Enzymes found in the mouth?
A substance that speeds up the process of a reaction.
Enzymes found in the mouth?
LipaseBegins to break down fats
AmylaseBegins to break down carbohydrates

7. Tongue
A muscle that helps food churn and form a ball for safe travel down the esophagus.

8. Esophagus
Esophagus a muscular tube lined with mucus that connects the mouth to the stomach.
Epiglottis prevents food from going down your trachea.

9. Peristalsis
Involuntary waves of muscle contraction that move food down the esophagus and throughout the digestive system.

10. Stomach J-Shaped muscular pouch
Chemicals called gastric juices (hydrochloric acid, pepsin) continue to break down food.
The food is moved around in the stomach and mixed with the chemicals for about 3 or 4 hours.
When it is done in the stomach, the food is now a cream-like liquid call chyme.
Now a valve at the end of the stomach opens sending the food past the liver.
The bottom picture is an empty stomach of a dog. When the stomach is full these ridges smooth out.

11. Liver/Gall Bladder The liver makes a chemical called bile.
Bile is stored in the gall bladder.
When the gall bladder mixes bile with our food, it does an important job: breaking down the fat (from milk, butter, cheeses) into tiny droplets. This fat will supply us with much energy later.

12. Pancreas
The pancreas also adds a digestive chemical as the food leaves the stomach.
This digestive juice works on breaking down the carbohydrates (from breads, potatoes, etc.) and the proteins (from meats, cereals, peanut butter).

13. Small Intestine Tube that is about 22 feet long! Made up of 3 parts:
Duodenum
Jejunum
Ileum
The chyme is now digested small enough to be put to use by the body.

14. Small Intestine - Villi
Along the walls of the small intestine are thousands of tiny fingers called villi.
Blood vessels in the villi can absorb the tiny food molecules and send them off to the rest of our body through the blood.

16. Large Intestine 5 foot long tube.
Whatever the body cannot put to use is sent to the large intestine.
The job of the large intestine is to remove water.
Water was necessary but it is no longer needed and is sent into the blood stream.
Food spends about hours in the large intestine where it become feces.

17. Rectum / Anus Rectum Short tube at the end of the large intestine
Waste material is compressed into a solid form
Anus  A muscular opening at the end of the rectum.