Alimentary Canal“The pathway for food”

1. Mouth- food is physically broken down by the teeth and tongue. It is chemically broken down by enzymes produced by salivary glands.

• Carbohydrates are changed from starch to sugar in the mouth by amylase.

3 salivary glands

Parotid (near the ear) is the largest.

Sublingual (under the tongue)

Submandibular (below the jaw)

2. Pharynx- Both air and food passes through. The epiglottis prevents food/liquids from getting into the airway.

3. Esophagus- peristalsis (involuntary muscle contractions that push the food down).

4. Stomach (2-4 hours)- cardiac sphincter, fundus, body, pyloric sphincter.

Enzymes• Pepsin (breaks down

protein)• Rennin (breaks down

milk)• Lipase (emulsifies

fats)• HCl (germicide and

breaks down fats)

5. Small intestine ( 6 meters in length). Food stays here for approx. 3-5 hours.Three sections

1. Duodenum “mixing bowl” 25 cm in length. Point where digestive juices from liver and pancreas enters the intestines.

2. Jejunum (2.5 m)- most of chemical digestion occurs here.

3. Ileum (3.5 m)- contains villi which absorbs broken down food and enters the bloodstream.

6. Large intestine- absorption of water and holds feces.

Four sections of the large intestine:

1. Ascending (going up)

2. Transverse (across)

3. Descending (going down)

4. Sigmoid (s-shaped)

7. Rectum- holding area for feces. Takes about 24 hours for food to reach this point.

8. Anus- most powerful sphincter in the body (and aren’t we glad!)