Physical and Chemical Changes in Digestion: Understanding the Role of the Digestive System, Study notes of Biological Systems

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Physical vs.

Chemical

Changes in

Digestion

What is

Matter?

• Anything and everything!
• Has MASS and TAKES UP SPACE!

Signs of Chemical Changes

• These changes alter the substance so that a

new substance with NEW properties appears

and is NOT easily reversible:

• Unexpected color change or odor
• Release of heat, light, or sound
• NOT easily reversible
• Produces gas or water, or formation of a solid
• NEW substance, with NEW properties

Test your real world skills!

• Color/dye your hair- physical or chemical?
• Bake a cake- physical or chemical?
• Ice cubes melting- physical or chemical?
• Rust on a nail- physical or chemical?
• Food breaking down in your stomach acid- physical or chemical?

Mouth

• Teeth cut, break and grind food into smaller pieces…. physical (mechanical) digestion
• Chewing mixes the food with saliva, from salivary glands around the mouth and face, to make it moist and easy to swallow.
• Enzymes in the saliva begin chemical digestion of carbohydrates (sugars) for energy

Esophagus

• A muscular tube
• It moves food by waves of muscle contraction called peristalsis.
• Physically moving the food along to the stomach.

Small Intestine

• Enzymes continue the chemica l reactions on the food, digesting of proteins, fats, and carbohydrates
• These nutrients are broken down small enough to pass through the lining of the small intestine, and into the blood (diffusion).
• Physically moves food to the large intestine.

Pancreas

• Accessory organ (you don’t NEED it to live)
• Food does not go through the pancreas (think of it as a “shower” of mild acids that help break down food in your small intestine)
• Produces chemicals to help break down macromolecules

Large Intestine (Colon)

• Physically ABSORBS (soaks up) extra nutrients & water
• Forms wastes into solid feces (poop )
• Physically moves feces to the rectum/anus

Rectum and Anus

• The last section of the digestive tract
• The rectum extends from the large intestine to the anus
• The anus is where feces is physically stored for elimination from the body.