1. How did you do?

2. Duodenum 1st section of small intestines pancreas liver gall bladder
Most digestion
acid food from stomach
mixes with digestive juices from:
pancreas
liver
gall bladder

3. Pancreas
Involved in the digestion of the three types of food molecules: carbohydrates, proteins, and lipids.
Digestive enzymes:
digest proteins
trypsin, chymotrypsin
digest starch
Amylase
Endocrine Function -secrete insulin and glucagon
Buffers
neutralizes acid from stomach

4. Liver
Organ involved with excretion, the recycling of useable materials, and the production of urea & bile
bile stored in gallbladder until needed

5. The liver
The average human liver weighs about 3.1 pounds and is about the size of a football!!
It provides a multitude of functions including:
Acts as a source for detoxifying the body of alcohol and poisons.
Builds proteins
Produces bile salts which are used to break down fats.
Metabolize and store carbohydrates, which are used as the source for the sugar (glucose) in blood that red blood cells and the brain use
Can supply quick energy to the body by releasing sugar.

6. Gall bladder
Pouch structure located near the liver which concentrates and stores bile
Bile duct – a long tube that carries bile. The top half of the common bile
duct is associated with the liver,
while the bottom half is
associated with the pancreas,
through which it passes
on its way to the small intestine.

7. Bile
Bile is a bitter, greenish-yellow alkaline fluid, stored in the gallbladder between meals and upon eating is discharged into the duodenum where it aids the process of digestion.
Bile acts like a detergent to emulsifies lipids (physically breaks apart FATS)
bile contains colors from old red blood cells collected in liver =
iron in RBC rusts & makes feces brown

8. mouth
break up food
digest starch
kill germs
moisten food
stomach
kills germs
break up food
digest proteins
store food
liver
produces bile
- stored in gall bladder
break up fats
pancreas
produces enzymes to
digest proteins & starch

9. Appendix Vestigial organ / bacteria storage?
Sac-like structure in humans found below the junction of the small and large intestine
Vestigial organ / bacteria storage?

10. Large Intestine
Specialized compartment of the digestive tube designed to collect undigested materials and reabsorb water
Prepares waste (feces) to be expelled from the body
Broken into 3 main parts:
Cecum
Colon
Rectum

11. Large Intestine Solid materials pass through the large intestine.
These are undigestible solids (fibers).
Water is absorbed.
Vitamins K and B are reabsorbed with the water.
Rectum- solid wastes exit the body.

12. Large intestines (colon)
Function
re-absorb water
use ~9 liters of water every day in digestive juices
> 90% of water reabsorbed
not enough water absorbed
diarrhea
too much water absorbed
constipation

13. Large Intestines cont…
** Undigested food and water enter the large intestine where water is absorbed.
Strong peristaltic action forces feces out through the rectum and the anus.

14. You’ve got company!
Living in the large intestine is a community of helpful bacteria
Escherichia coli (E. coli)
produce vitamins
vitamin K; B vitamins
generate gases
by-product of bacterial metabolism
methane, hydrogen sulfide

15. Rectum Last section of colon (large intestines) undigested materials
eliminate feces
undigested materials
extracellular waste
mainly cellulose from plants
roughage or fiber
masses of bacteria

16. Defecation
the act or process by which organisms eliminate solid or semisolid waste material from the digestive tract.
Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum.
Undigested food may also be expelled this way; this process is called egestion

17. MECHANISM FOR CHEMICAL DIGESTION
Hydrolysis - the splitting of large, insoluble molecules into small, soluble molecules with the addition of water

18. Hydrolysis cont..
** In organisms, this process is regulated by hydrolytic (digestive) enzymes and is illustrated by the following:
1. Maltose + water ----> simple sugars (glucose)
2. Proteins + water ---> amino acids
3. Lipids + water ---> 3 fatty acids + glycerol

19. Hydrolysis cont…
In a similar fashion, polysaccharides such as starch are completely hydrolyzed to simple sugars. + =

21. Ingestion
Mechanical Digestion
Chemical Digestion

22. Mouth Salivary amylase - Breaks down starches into disaccharides
Lingual lipase – breaks down triglycerides into Free fatty acids, and mono- and diglycerides

23. Stomach
Pepsin – breaks proteins down into polypeptides

24. Small Intestine (from pancreas)
Pancreatic Amylase – continues breakdown of starches
Trypsin – hydrolyzes proteins and large polypeptides into smaller polypeptides
Nucleases – break down nucleic acids
Pancreatic Lipase – Breaks down fat with help from bile

25. Action of Bile Bile is not an enzyme
It allows enzymes to interact more effectively with enzymes secreted by the pancreas
Non-polar regions cling to fat molecules and the like polar regions repel
Fatty molecules are pulled off of large fat molecules increasing surface area, making them easier to break down

26. Small Intestine
Maltase, Sucrose and lactase – continue breakdown of carbohydrates
Peptidases-Break down dipeptides into amino acids

28. Practice Tracing Food through the Digestive System: http://kitses