Digestive System

1 Function:• Break down food into small molecules so it

can be absorbed and moved by the blood which delivers it to your cells for energy.

2 Types of digestion

2 types of digestion

• Mechanical: food is cut, mixed, or churned into smaller pieces.

2 types of digestion

• Chemical: saliva, bile, and acid help break down or dissolve the chemical bonds of the food molecules

The Path of Food

1. Ingestion (eating)

2. Digestion (breaking down food molecules)

3. Absorption (by cells)

4. Elimination (disposal of unused food)

Organs of the Digestive System

1. Food is chewed in the mouth• Mechanical-chewing and ripping it into smaller

pieces• Chemical-saliva starts to dissolve starches

http://www.youtube.com/watch?v=CsYbO6zBR74

2. Slimy pieces of food slide down the pharynx, past the epiglottis, into the esophagus

http://www.youtube.com/watch?v=QvGYvK6qScE&feature=related

3. Food is squeezed down the esophagus by muscle contractions called peristalsis.

4. Food lands in the stomach• Mechanical digestion-food is churned and mixed• Chemical digestion-food is mixed with enzymes

and acids to break it down.

http://www.youtube.com/watch?v=cp-SEs6dxR8&feature=relatedheartburn video

5. 2-4 hours later, food is now a watery liquid and it slowly moves into your small intestine.

Stomach Stapling

Stomach size is reduced and

intestinal length is shorted to reduce

the amount of food stored and calories

absorbed.

This reduces the size of the

stomach and small intestine, thereby restricting food

intake and caloric absorption.

Small Intestine6. In the small intestine food is digested even

more and then absorbed by the bloodstream.

7. Fat is chemically digested in the small intestine by bile. The liver makes bile and extra bile is stored in the gall bladder

• Carbohydrates, proteins, and fats are also chemically digested by a digestive solution made by the pancreas.

8. Millions of villi in the small intestine allow the blood to pick up the nutrients (absorb) to deliver to cells around the body.

http://www.youtube.com/watch?v=xu5jDCX2cHM http://www.youtube.com/watch?v=_GTQBiZni6w

9. Remaining food and liquid is moved into your large intestine by peristalsis.

10. Water is absorbed from the large intestine back into the body.

http://www.youtube.com/watch?v=PpzfKt-47iA&feature=related

11. Remaining food is compacted and released from the body as feces through the rectum and anus.

The End!

1. Mouth

2. Salivary Glands

3. Gall Bladder

4. Liver

5. Pancreas

6. Small Intestine

7. Esophagus

8. Stomach

9. Large Intestine

10.Rectum

11.Anus

Review of digestion

1. Draw a plate of food

a. Mechanical digestion by teeth (tear dinner in half)

b. Chemical digestion by saliva (tear dinner in half again)

2. Food goes into the mouth

3. Food moves into the esophagus

No digestion occurs

4. Into the stomach

a.Mechanical digestion churning muscles (tear pieces in half)

b. Chemical digestion by acid (tear pieces in half again)

5. Into the small intestine

a. Chemical digestion by bile (tear pieces in half again)

b. Absorption by blood stream (I will come around and collect some nutrients)

6. Into the large intestine

a. Absorption of water by blood stream (I will come around and collect some water)

7. Elimination of unused food

a. Form compact feces from remaining food particles (I will come around and collect the

feces)