1. DIGESTIVE SYSTEM

2. FUNCTIONS
Digestion
Absorption
Elimination

3. DIGESTION
Digestion – the mechanical and chemical breakdown of foods for use by the body’s cells.
Types of digestion include:
Mechanical Digestion – when teeth or the stomach break up food into smaller pieces
Chemical Digestion – when food is broken down into simpler substances due to the action of enzymes.

4. ABSORPTION
Absorption – the passage of digested food from the digestive tract into the bloodstream or cardiovascular system.
Nutrients are absorbed into the blood and delivered to all the cells of the body through the cardiovascular system
*Nutrients absorbed – Carbohydrates, Proteins, Fats, Vitamins, Minerals

5. ELIMINATION
Elimination – the expulsion of undigested food or body wastes

6. STRUCTURES OF THE DIGESTIVE SYSTEM
Teeth are used to break up food, a process called chewing or mastication.
MASTICATION = chewing
Salivary Glands – produce saliva in the mouth that contain enzymes that start to break down certain foods in the mouth
Saliva also lubricates food making it easier to swallow

7. STRUCTURES
The tongue forms and pushes chewed food towards the throat or pharynx.
As you swallow, muscular contractions force food into the pharynx.
The uvula, a small flap of tissue in the back of the throat, closes the opening to the nasal passages.
The epiglottis, another flap of tissue covers the windpipe, also known as your trachea.

8. DIGESTIVE TRACT
Alimentary Canal – takes in food, digests it, extracts nutrients, and expels water
30 foot long tube that opens at both end; food passes through

9. PARTS OF THE DIGESTIVE TRACT
Mouth – forms bolus
Bolus – ball shaped through chewing and swallowing food; mixed with saliva
Voluntary and Involuntary
Physical and chemical breakdown of food by process of chewing

10. PARTS CONTINUED Pharynx – located in the neck and throat
Food and air pass through here
Transports food to stomach
Involuntary

11. PARTS Esophagus – 10 inch tube transports food to stomach
Peristalsis – contraction of muscles to propel food down (bolus)

12. PARTS Stomach Chemical and Physical breakdown of food
Chyme – mixture of gastric juices and food
Food stays in the stomach for about 3 – 5 hours

13. PARTS Small Intestine – 20 foot long tube 3 parts:
Duodenum – first 10 inches of the small intestine; extract nutrients
Jejunum
Ileum
Absorption – nutrients absorbed into the blood stream

14. SMALL INTESTINE PARTS

15. PARTS Large Intestine – 5 – 6 foot long tube
Organization of wastes and feces
Undigested food turns into feces
Appendix – about 4 inch thin tube; no known function
Cecum – beginning of the large intestine; receives fecal matter from the Ileum

16. LARGE INTESTINE

17. PARTS Rectum – stores feces Anus – releases feces
Ring of muscle, expelling unwanted solid matter
Sphincter – circular muscle that normally maintains constriction of a natural body passage

18. ORGANS THAT HELP IN DIGESTION
Liver – produces bile
Bile – dark green to yellowish brown fluid that aids in digestion in the small intestine
Stores glucose (sugar) and iron
Pancreas – digests sugar
Produces enzymes that break down carbohydrates, fats, and proteins in food
Enzymes – any proteins that cause a chemical reaction

19. ORGANS CONTINUED Gallbladder – stores bile in between meals
At meal time, bile is secreted into the bile duct to reach the small intestine (duodenum) and mix with the fats in foods
Bile dissolves fats into watery contents
After dissolved, its digested by the enzymes made in the pancreas

20. FUN FACTS Carbohydrates digest first, proteins next, and fats last
It takes about 12 – 72 hours to digest food, depending on what type of food you eat
Water helps in digestion