Mouth Mechanical Digestion –Teeth and tongue break food down into smaller pieces Chemical Digestion –Salivary glands produce saliva –Chemicals (Enzymes) in saliva begin to break down food –Amylase breaks down starch into glucose Your body produces 1.5L of saliva each day!

Esophagus Muscular tube that connects mouth to stomach Involuntary smooth muscles contract in a wavelike motion called peristalsis to move food

Stomach Food stays in the stomach for 3-4 hours! The stomach is a bag-like organ with 3 muscular layers Sphincters control movement of food in and out

Chemical Digestion –Cells in the stomach lining secrete gastric juices- which include water, acids, mucus and enzymes –Mucus protects the stomach lining –Enzymes break down proteins Ie) pepsin Mechanical Digestion –Muscles contract (churn) to mix food (peristalsis) What is Chyme?

Intestine Extends from the stomach to anus Peristalsis moves partially digested food along SI

Small Intestines Where most digestion and absorption occurs 3 Parts: Duodenum- 25 cm (shortest and widest) Jejunum- 2.5m Ilieum- 3m Total- 6m long, 2.5 cm in diameter Chemical Digestion from enzymes of chyme

Liver and Gall Bladder Largest internal organ Produces bile- an emulsifying agent needed to digest fats Gall Bladder - underneath liver, small spherical organ –Bile is stored in gallbladder until it’s needed

Chyme –the partly digested food (texture similar to porridge) –Very acidic (pH 2.5) Pancreas- leaf shaped organ under stomach - secretes pancreatic juices- include sodium bicarbonate and enzymes –sodium bicarbonate raises pH to about 9 (neutralizes acid coming from stomach) - digestive enzymes: ie) lipase- breaks down fat and trypsin breaks down proteins

Large Intestine Your L.I. reabsorbs almost 10L of water daily! Inverted U shaped organ, surrounds SI 1.5m long, 7.5 cm in diameter It concentrates the waste by absorbing water from undigested food

Anus Muscular organ controlled by two sets of sphincters Solid matter left behind is eliminated from the anus as feces