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DIGESTION. Major Functions of the Digestive System. Digestion- Breaks down food into usable molecules Absorption- Absorbs food molecules into the bloodstream Elimination- Eliminates solid wastes. Two Types of Digestion:.
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Major Functions of the Digestive System • Digestion- Breaks down food into usable molecules • Absorption- Absorbs food molecules into the bloodstream • Elimination- Eliminates solid wastes
Two Types of Digestion: • Mechanical Digestion • Foods are physically broken down into smaller pieces • Chemical Digestion • Chemicals break foods into smaller chemical building blocks
The digestion Pathway
The Mouth • Chews food (MechanicalDigestion) • 2. Saliva moistens food • Salivary amylase (enzyme) breaks down starch (Chemical Digestion) Starch Glucose Energy
The esophagus • Strong muscular tube that connects mouth to the stomach • Epiglottis- seals off the windpipe • Mucus- thick slippery substance • Peristalsis- smooth muscle contractions
THE STOMACH • Most mechanical digestion • occurs here 2. Pepsin chemically breaks down protein 3. Hydrochloric acid helps pepsin and kills bacteria 4. Mucus protects the stomach lining
SMALL INTESTINE • 6meters long • Carries out almost all chemicaldigestion and absorption • Lined with villi to increase absorption
LARGE INTESTINE • 1.5 meters long • Absorbs water from wastes • Bacteria help digestion and produce vitamins • Wastes are stored in the rectum and eliminated through the anus.
The Helper Organs (match organ to function) Liver Makes enzymes Gallbladder Makes bile to break up fats Pancreas Stores bile
Liver, gallbladder & Pancreas