1. Digestion
Function:
Food is broken down by the digestive system into a usable form the cells can use.

2. Where does the digestive system start and end?
Mouth
Pharynx
esophagus
stomach
small intestine
large intestine (also called the colon)
rectum
anus

3. Enzymes help speed up the changing of food into a usable form
Fats, proteins and carbs must be broken down by enzymes
Vitamins, Minerals and water do not have to be broken down.

4. II. Trip through the Digestive System
1. Mouth
2. Esophagus
3. Stomach
4. Small Intestine
- pancreas
- liver
- gallbladder
5. Large intestine
6. Anus
Organ Chart
SNEAK PEEK

5. 1. Mouth: Where food enters Time spent: Few minutes
Production of saliva is the first step in digestion (sometimes before you even start eating)
Tongue moves it around and the saliva produced coats and lubricates the food for easier chewing and swallowing.
Teeth cause only a mechanical change.
Saliva also contains an enzyme called amylase
chemically break down certain carbohydrates

6. 2. Pharynx Tube connecting mouth to the esophagus
As you swallow the epiglottis covers the windpipe so food does not go down the wrong tube.
Lasts a few seconds
No digestion occurs here

7. 3. Esophagus Tube connecting mouth to stomach Few seconds
No digestion occurs here
Peristalsis (muscle contractions) send the food down the tube until it reaches the sphincter (start of the stomach)
Esophagus video

8. 4. Into the Stomach
As food approaches, the sphincter valve opens causing food to go into the stomach.
Time spent: 4 hours
Physical change: mixes and churns the food
Chemical change: 2 enzymes - Pepsin and Rennin
Acid that breaks down food
and bacteria
Stores and processes food.

9. Chemical change in the stomach
Pepsin: breaks down protein
Rennin: enzyme that turns milk into cheese
Let’s view the stomach!

10. 5. Through the Small Intestine
Most chemical digestion and absorption occurs here!
18-39 feet long on average... That's 4 -5 x's longer than you!
The small intestine itself does not make enzymes, but 3 other organs not in the digestive tract deliver enzymes to the small intestine
All 3 nutrients are digested via 3 other organs
Time: 12 hours to digest and absorb

11. Three parts to the Small Intestine:
1. Duodenum
Located at the junction
of the stomach and the
small intestine
Receives bile from the gallbladder, and other digestive enzymes from
the pancreas
Bulk of the digestion of proteins, fats and carbohydrates takes place in the duodenum before the material travels further into the small intestine

12. Three parts to the Small Intestine:
2. Jejunum
coiled mid-section of the small intestine
3. Ileum
final portion of the small intestine, which leads into the large intestine
contain very small finger-like bumbumps called 'villi‘, which improves the small intestine's ability to absorb nutrients.

13. The Pancreas The pancreas produces 3 enzymes Lipase: breaks down fats
Protease: Breaks down protein
Amylase: Breaks down carbs
Delivers these enzymes to small intestine through the pancreatic duct
pancreas is a small flat organ (about cm long) that is located behind the stomach and sits close to the duodenum

14. The Liver: Largest organ of the body (except the skin) Makes bile:
liver is the body's 'detoxifier‘
Ammonia - a toxic product arising from the digestion of proteins, is converted into the less toxic 'urea' by the liver and then transferred to the kidneys
Largest organ of the body (except the skin)
Makes bile:
BILE: Green, smelly liquid
Breaks fats into smaller fat droplets
Delivers the bile to the gallbladder for storage
Located in the upper abdomen to the right of the stomach, below diaphragm

15. The GallBladder Stores Bile (physical change)
Delivers the bile when needed to the small intestine via the Hepatic Duct
If the bile hardens it forms gallstones.
small (10 cm long) pear-shaped organ that is located near the duodenum and the liver.

16. How are nutrients absorbed?
Absorption: movement of chemicals into or out of an organ
Has villi on the inside that have blood vessels that carry nutrients throughout the body
Villi increase the intestinal surface area
More surface =more absorption

18. 6. Large intestine
Once in the large intestine: digestion is already complete.
Large intestine only does physical changes: removes water from undigested food and begins to produce feces.
Time: 4 hours
3 parts: Ascending (up)
Transverse (across)
Descending (down)
Also contains: caecum, appendix, colon and rectum

19. 7. ANUS: Where waste is excreted!
Appendix
has no known function and is thought to be a remnant from a previous time in human evolution.
Rectum
rectum is the final part of the large intestine.
where stool (feces) is stored before being passed as a bowel motion.
7. ANUS: Where waste is excreted!
Nervous system triggers the urge to pass stool
Surrounded by strong sphincter muscles.

20. Problems of Digestive System -Heartburn
Acid moves into the esophagus
Caused by eating too much food
Many people get acid reflux disease
Take an antacid such as rolaids, tums, pepto-bismol

21. Problems Of Digestive System -Gallstones
Bile stores up and hardens either in the liver or the gallbladder
Block pathways for digestion
have to have them surgically removed

22. Problems of Digestive System ULCERS
Sore or hole on inside the stomach or small intestine
Caused by too much HCl & pepsin being produced
Enzymes eat away at stomach lining
Causes burning sensation in stomach
Stress can bring on an ulcer or it is just natural production of too much acid
Prescribed medicine for extreme cases
Minor cases can uses Pepsid AC

23. Problems of Digestive System -Appendicitis
Swelled appendix
Bacteria builds up from stuck food
Causes severe pain on lower right side of body
Appendectomy – the removal of the appendix

24. Problems of Digestive System Constipation
Too much water is absorbed by the large intestine
Can be a virus or something one eats
Over the counter medicines usually take care of the problem
Pepto-bismol, eating more roughage (lettuce), etc.

25. Problems of Digestive System Diarrhea
Not enough water is absorbed by the large intestine
Runny stools
Caused by bacteria or virus or something one ate
Over the counter medicines such as pepto-bismol will help