Digestive SystemDigestive System

Digestive System Rap

Job of Digestive SystemJob of Digestive System

Break down food (macromolecules) into nutrients & energy

Review: MacromoleculesReview: MacromoleculesWhat macromolecules do we eat?Proteins: Meat, Nuts Lipids: Oils, FatsCarbohydrates: Breads, Sugars

Review: Food EnergyReview: Food EnergyWhich macromolecule is our main energy source?

Carbohydrates

Which macromolecule stores the most energy?

Lipids

Review: Food Energy (cont.)Review: Food Energy (cont.)

The Food PyramidThe Food Pyramid

NutritionNutrition

Nutrients: Anything that promotes growth

Vitamins (Vitamin C) Minerals (Iron) Macromolecules

Two Types of DigestionTwo Types of Digestion

Mechanical – physically breaking food into smaller pieces (mouth)

Chemical – food molecules are broken down by acids and enzymes (stomach, small intestines)

Digestive SystemDigestive System

Tracking a Piece of FoodTracking a Piece of Food

1. Mouth2. Esophagus3. Stomach4. Small Intestine5. Large Intestine6. Rectum 7. Anus

SwallowingSwallowing

Peristalsis: wavelike movement of muscles pushes food through digestive tract

My food went down the My food went down the “wrong pipe!”“wrong pipe!”

2 tubes in throat: trachea & esophagus

esophagus connects mouth to stomach How does food know which tube to go down?

epiglottis

3 Jobs of Stomach3 Jobs of Stomach

1. Store food & liquid2. Mix food & digestive

juices (HCl)3. Empty into small

intestine

Digestive JuicesDigestive JuicesAssist in breaking down of food

Ex. Enzymes

Acid Reflux

Small IntestineSmall IntestineAbsorbs greatest amount of nutrients

Covered with tiny finger-like projections – villi

~20 ft long!

VilliVilli

Increase surface area

for better absorption (like a towel)

Large IntestineLarge IntestinePrepares waste for removal by absorbing water

~5 ft long!

Digestion: ‘Helper’ OrgansDigestion: ‘Helper’ OrgansSalivary Glands: produce saliva – starts breaking down carbohydrates

Pancreas: produces enzymes & regulates

glucose levels

Liver:Produces bile

Filters blood

Digestion: ‘Helper’ Organs Digestion: ‘Helper’ Organs (cont.)(cont.)

Gall Bladder: stores bileHelps digest fatty foods

Digestion: ‘Helper’ Organs Digestion: ‘Helper’ Organs (cont.)(cont.)