5/14/12 pgs. 147-148 the digestive system: part 1

5/14/12

pgs. 147-148

The Digestive System: Part 1

KnowWhat are the functions of the digestive system? (There are three of them– take your best guess.)

Evidence: Draw, Label and color the digestive system diagram on TB page 519

The Digestive System – Part 1

“I don’t know any.” is not an acceptable answer.

Clarifying ?s Informationfunctions

3. Eliminate wastes from the body.

1. Break down food

2. Absorbed food molecules into blood to be carried throughout the body.

- The process of the body breaking down food into small nutrient molecules

2. Chemical – Enzymes produced by the body are used to break food down to its smallest components.

Example: take bite of food, teeth break/grind it, saliva makes the food moist.

Two kinds of digestion

1. Mechanical – Food is physically broken down into smaller pieces

digestion


Example: The starches in bread and potatoes are broken down into sugar molecules.

Clarifying ?s Information

1. Food enters mouth and teeth and jaws cut and grind it for swallowing. (mechanical)

The process of digestion

2. Saliva coats food – 2 functions: 1. lubrication for easy swallowing, 2. Enzymes in saliva begin breaking down food. (chemical)

- a protein that speeds up a chemical reaction. Each enzyme has a specific job

Example: A starch enzyme cannot break down a protein.

enzyme



Summary:


3. Food is swallowed. (mechanical) Epiglottis blocks route to lungs – prevents gagging and breathing obstructions.

4. ring-like muscles in esophagus contract, which pushes food toward stomach. (mechanical)

5. Food enters stomach: food is squeezed, churned, and mixed. (mechanical)

6. Food mixes with stomach acid, which continues breaking down food. (chemical)

7. Food leaves the stomach as a thick liquid.


Clarifying ?s InformationThe Digestive System – Part 1

functions

3. Wastes are eliminated from the body.

1. Break down food into molecules that the body can use.

2. Molecules are absorbed into the blood and carried throughout the body.

- The process of the body breaking down food into small nutrient molecules

2. Chemical – Enzymes produced by the body are used to break food down to its smallest components.

Example: When you take a bite of food, teeth break it apart and grind it while saliva makes the food moist.

Two kinds of digestion

1. Mechanical – Food is physically broken down into smaller pieces

digestion

Example: The starches in bread and potatoes are broken down into sugar molecules.

- a protein that speeds up a chemical reaction. Each enzyme has a specific job

Example: A starch enzyme cannot break down a protein.

enzyme


Summary:


1. Food enters mouth and teeth and jaws cut and grind it for swallowing. (mechanical)


2. Saliva coats food – 2 functions: 1. lubrication for easy swallowing, 2. Enzymes in saliva begin breaking down food. (chemical)3. Food is swallowed. (mechanical) Epiglottis blocks route to lungs – prevents gagging and breathing obstructions.4. ring-like muscles in esophagus contract, which pushes food toward stomach. This is called peristalsis and only works in one direction. (mechanical)5. Food enters stomach where food is squeezed, churned, and mixed. (mechanical)6. Food mixes with mild hydrochloric acid in the stomach, which continues breaking down food. (chemical)7. Food leaves the stomach as a thick liquid.

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5/14/12 pgs. 147-148 the digestive system: part 1

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