1. What process moves food through the digestive system?
Peristalsis
What keeps food from splashing back up your esophagus?
Cardiac sphincter
What is a science word for pooping?
Egestion
What two functions does the small intestine perform?
Digestion and absorption
What does the large intestine absorb?
water

2. Mouth and Stomach

3. The tongue Papillae Tongue Taste Buds
When you chew food into smaller bits some of them dissolve into your saliva (physical digestion)
Once food particles are in solution the taste buds on the tongue can detect them
Amylase, an enzyme in your saliva, starts to break down polysaccharides into disaccharides (chemical digestion)
Tongue detects: sweet, sour, bitter, salty and Umami
Papillae
Tongue
Taste Buds

4. The tooth Dentin: similar to bone Enamel:
Made from calcium. Hardest part of the body
Crown
Pulp cavity: contains nerves and blood vessels
Root
Root canal

5. Teeth Canines: For tearing into food (meat!)
Molars: For crushing and grinding food
Premolars: For grinding food
Incisors: For biting off bits of food

6. Stomach The stomach lining is called the ‘lumen’
It is covered in mucus that protects it from the acidic environment in the stomach (the acid HCL is part of gastric juices and makes the stomach have a pH of around 2.5)
Food entering the stomach triggers the release of the hormone gastrin
Gastrin tells special cells in the lumen to make gastric fluids

7. The stomach moves (churns) which physically breaks down food
The gastric fluids in the stomach contain:
pepsin, an enzyme that breaks proteins into smaller polypeptide chains
HCL, which kills invading pathogens and activates the pepsin (from its dormant storage form: pepsinogen)
Rennin, an enzyme that slows the movement of milk through the digestive tract of infants by causing it to curdle and clump up (so it has time to be absorbed in the small intestine) Rennin has little affect in the stomach of adults