1. Digestion

2. Colorado State Established in 1870, Fort Collins Colorado.
College Highlight:
Colorado State
Established in 1870, Fort Collins Colorado.
Ranked nationally for its science and engineering programs

3. What is Digestion?
The process of converting food into simpler molecules that can be absorbed by cells and used within the body.

4. The Digestive System Mainly Includes:
The mouth
Esophagus
Stomach
Small Intestine
Large Intestine
Rectum

5. Accessory Organs An organ that helps with digestion but is not part of
the digestive tract.
These organelles add
secretions to the digestive
system
Salivary Glands
Tongue
Pancreas
Liver
Gallbladder

6. The Mouth Teeth physically break apart food
The process of chewing begins the early stages of mechanical digestion
Digestive enzymes released from salivary glands begin breaking down carbohydrates into smaller molecules (chemical digestion)

7. Saliva Helps to moisten food Makes food easier to chew
The amount of saliva released is controlled by the nervous system
You often produce saliva in the presence of the smell of food
Saliva contains salivary amylase, an enzyme that breaks the bonds of starches into sugar (glucose)

8. Esophagus Esophagus is most commonly referred to as the food pipe
It connects the throat (pharynx) to the stomach
Once the food is chewed and becomes a clump it is referred to as the bolus
The bolus is propelled down the throat via peristalsis

9. Peristalsis
Peristalsis is the contraction of the throat that moves the bolus downwards towards the stomach

10. Epiglottis
The epiglottis is a flap of connective tissue that separates the trachea away from the esophagus

11. Stomach The esophagus empties the bolus into the stomach
Large muscular sack that continues mechanical and chemical digestion
The three layers that churn and mix food with mucus and gastic juice secreted from the lining of the interior of the stomach
Extremely acidic with a pH of 1
Mucus functions to protect the interior lining of the stomach from itself

12. Stomach Cont
High acidity activates pepsin an enzyme that begins the digestion of protein
Because enzymes that break down carbohydrates cannot function in high acidity they no longer break down carbohydrates in the stomach
Chyme is what is produced by the stomach
Chyme travels from the stomach through the pyloric valve into the small intestines

13. The Small Intestines
Small intestines is made up of three parts, the duodenum, the jejunum and the ileum
6-7 meters long
Secretes peptidase that breaks dipeptides into amino acids
Secretes other enzymes that break down disaccharides into monosaccharides

14. The Pancreas Does not directly participate in digestion
A gland that secretes the enzymes amylase, trypsin, and lipase into the small intestines
Amylase breaks down carbohydrates
Trypsin breaks down proteins
Lipase breaks down lipids

15. Liver Aids the pancreas Has right and left lobe
Produces bile, a fluid that consists of lipids and salts.
Bile dissolves and disperses fat droplets found in fatty foods
Bile is stored in the gallbladder

17. Absorption in Small Intestines
Villi are fingerlike projections that line the surface of the small intestine
They are adapted for the absorption of nutrients
Villi are covered in more projections called microvilli
The increased amount of surface area allows for rapid absorption of nutrients
By the time the food is leaving the small intestines it has been depleted of all its nutrients

19. Large Intestines Also known as the colon
Functions to remove water from undigested material
Water is absorbed quickly across the wall of the large intestines
The concentrated waste that remains once water has been removed is excreted out of the body through the rectum