V. The Digestive System

I. Terms You Should Know

A. Digestion Process of breaking down food into

smaller partsB. Mechanical/Physical Digestion

Examples: Chewing/Crushing/Tearing food

C. Chemical Digestion Use of enzymes to break down food

D. Absorption Take in nutrients/molecules in the body

II. Mouth

A. Teeth

1. 32 Teeth Total2. Incisors

Front Rip/Tear Food

3. Canines “Fangs” Hold Food

4. Molars Back Grind Food

5. Wisdom Teeth Develop in later years Used to replace lost teeth

B.Tongue

1. Helps move food

Muscle2. Taste

Tastebuds on surface

C. Salivary Glands

1. Produces Saliva2. Moistens/ softens food3. Lubricates Mouth4. Amylase

Enzyme that breaks down starches & carbs

E. Epiglottis

1. Flap that covers the trachea when you swallow

Prevents food from going down your windpipe

D. Pharynx

1. Receives the food from your mouth2. Swallowing takes place here3. Located in the back

III. Esophagus

A. Tube to Stomach

B. Peristalsis1. Wave-like muscle contractions that move food

IV. Stomach

A. Gastric Juices/Fluids

1. Pepsin & Hydrochloric Acid

Break down proteins during digestion

2. Mucus Lining of stomach Necessary in

order for stomach to not “eat itself”

B. Chyme

1. End product of stomach digestion2. Takes stomach about 40 minutes to get to this point3. Greenish in color

V. Small Intestine

Where most chemical digestion takes place

A. Duodenum

1. First 25 cm of small intestine2. Horseshoe shape

B. Intestinal Glands

1. Produce substances to neutralize acids from food in stomach

C. Intestinal Secretions

1. Pancreas Digests: Carbs,

Proteins, & Fats2. Liver

Gall Bladder▪ Stores bile

Bile▪ Digests fat▪ Greenish in color

D. Food Absorbed

1. Villi Tiny fingerlike

projections in stomach Food absorbed here Increases surface area Microvilli (even

smaller)2. Fats enter bloodstream3. Diffusion – allows nutrients from food to enter blood

E. Appendix

1. Current function is unclear2. One theory is that it used to store good bacteria for the body

F. Large Intestine/Colon

1. Involved with waste products2. Absorb water3. Large amount of bacteria found in these locations

G. Anus

1. Opening at the opposite end of the digestive tract from the mouth2. Control expulsion of unwanted semi-solid matter

Digestive System Diagram