1. Digestive System What is digestion and where does it start?

2. The Digestive System  Digestion  Absorption  Elimination

3. Digestion  Mechanical break down of foods  Teeth-break down food into small pieces  Masticaiton—process of chewing  Chemical break down of foods  Saliva-produced by the salivary glands; the first juices used in the process; break down starches and sugars in foods; lubricates food making it easier to swallow.  Both for use by the cells of the body

4. Digestion  Chemical break down of foods  Saliva-produced by the salivary glands; the first juices used in the process; break down starches and sugars in foods; lubricates food making it easier to swallow.  Bile  Stomach acids  Enzymes  Pepsin

5. Digestion  Tongue  Forms chewed food into a size and shape that can be easily swallowed  Esophagus  10” muscular tube that connects the pharynx with the stomach

6. Digestion  Peristalsis  A series of involuntary muscle contractions that move food through the digestive tract  Esophagus  Stomach  intestines

7. Digestion  Stomach  Hollow, sac-like organ surrounded by muscles which allow for expansion during ingestion.  3 Jobs  Mix foods with gastric juices  Store swallowed food and liquid  Move food into small intestine

8. stomach  Mix food with juices:  Secretions from the stomach lining that contain HYDROCHLORIC ACID,& PEPSIN, an enzyme that breaks down proteins  HCL—kills bacteria in food and creates an acidic environment for the pepsin to do its job  Mucus in the lining of the stomach protects the stomach from being digested in its own juices

9. stomach  Chyme  The creamy fluid mixture of food and gastric juices formed in the stomach.  YUCK!!! But it is what it is!!! :~)

10. Indirect Digestive Organs  Pancreas  Liver  Gall Bladder

11. pancreas  Organ that produces enzymes that break down the carbohydrates, fats, and proteins we consume.  Organ that is essential in insulin (blood sugar regulator) control.—Diabetes I and II.

12. liver  Organ that produces bile  Yellow-green fluid that helps break down and absorb fats  Jaundice—when the liver is not functioning properly the skin and eyes can become yellow from an excess of bile in the system.

13. gall bladder  Connects liver to digestive tract as a gateway for the bile  You can live without, but fatty foods will affect the body more than a body with a gall bladder.  Can become filled with painful gall stones

14. Absorption  Passage of digested food from the digestive tract into the cardiovascular system through capillaries in the villi of the intestines

15. absorption  Small Intestine  20-23’ long  1” diameter  Finishes digestion and begins absorption in the villi—finger-like projections in intestines  Large Intestine (colon)  5-6’ long  2.5” diameter  Finishes absorption and begins elimination

16. Elimination  Expulsion of undigested food or body wastes  Begins with large intestine—eliminate feces  Skin excretes some wastes through the pores—sweating  Lungs expel CO2 and other gas wastes  Liquids are filtered to the urinary tract for expulsion