Digestive System

2 Types of Digestion

•Mechanical – Breaks down food PHYSICALLY/MECHANICALLY• Chemical – Breaks down food

using CHEMICALS

The Mouth

• Tongue – Moves food around

• Incisors – Sharp – Cut food

• Canines – Pointed – Tear Food

• PreMolars/Molars – Flat – Grind Food

• Salivatory Glands – Produces Saliva

Mechanical or Chemical?

Teeth Breaking Food Up into Smaller Pieces

Mechanical or Chemical?

Teeth Breaking Food Up into Smaller Pieces

MECHANICAL

Mechanical or Chemical?

Tongue Pushing Food Around

Mechanical or Chemical?

MECHANICALTongue Pushing

Food Around

Mechanical or Chemical?

Saliva Breaking food upUsing enzymes

Mechanical or Chemical?

CHEMICALSaliva Breaking food up

Using enzymes

Mouth and Throat

• Pharynx – Upper portion of throat

• Larynx – Where throat separates from lungs and esophagus/ Voice box

• Trachea – Windpipe – leads to the lungs

Mouth and Throat

• Epiglottis – Flap that prevents food from entering lungs

• Esophagus – Tube connecting mouth to stomach

Esophagus

• Uses PERISTALISIS to MOVE food down to the stomach

• PERISTALISIS = CONTRACTIONS• Lined with mucus – helps food travel down to

stomach

• Sphincter is found at end of esophagus – preventing food/acid from traveling back up!

Mechanical or Chemical?

PERISTALISIS movingFood down esophagus?

Mechanical or Chemical?

MechanicalPERISTALISIS moving

Food down esophagus?

STOMACH

• Sloshes food around – mixing in ACIDS and ENZYMES

• Pepsin (enzyme) breaks down proteins• Food turns into thick liquid

Mechanical or Chemical?BOTH!!!Sloshing and Grinding = MechanicalAcids and Enzymes = Chemical

Small Intestines

• DUODENUM (beginning) – Continues to BREAK DOWN FOOD

• JEJUNUM (middle section) – Nutrients are Absorbed

• IlEUM (end section) – Nutrients are absorbed

• Food moves through PERISTALSIS (contracting waves)

Support for Small Intestines

Liver

StomachGall Bladder

Pancreas

Liver

• LARGEST ORGAN IN THE BODY!!!!• Produces BILE

BILE

Gallbladder

• Breaks up fat particles• Not an enzyme! Similar to soap in grease –

breaks it into small bubbles of grease

• Sack that holds BILE• Squirts bile into duodenum

Pancreas

• Produces enzymes• Breaks down starches, proteins, and fats

Absorption in Small Intestine

• Villi – finger-like things that have blood vessel inside. Nutrients enter blood through VILLI

Appendix

• At start of Large Intestine

• Hypothesized that it stores extra “good” bacteria, used in severe cases of dysentery

• Is safe to remove

Large Intestine

• Water Absorption

• Bacteria present to further break down VITAMINS

• Also known as COLON

End of Large Intestine

• Rectum – – Waste is collected; – Compressed into solid form

• Anus – – Sphincter that releases waste