1. Presented By: Sam Lund, Donovan Parker, Tom Srebernak
The Digestive System
Presented By: Sam Lund, Donovan Parker, Tom Srebernak

2. Goals of the Digestive System
1. Extract nutrients from food
2. Transform nutrients into useful forms
Ex. Oreo= Glucose (sugar)
3. Absorb nutrients and distribute them where they are needed

3. Functions of the Digestive System
Ingestion: Intake of nutrients
Digestion: Breakdown of large particles into smaller ones
Absorption: Uptake of nutrient molecules
Defecation: Elimination of undigested residues

4. Actions of the Digestive System
1. Intake
Breaks up food
Moves food through the GI tract (Peristalsis)
Mixes with digestive enzymes
2. Secretion
Release of enzymes and hormones for chemical digestion and regulation
3. Membrane Transport
- Absorption of nutrients from the tissues by the blood and lymph for transport

5. Stages of Digestion Mechanical: Physical breakdown of food
Chemical: Digestive enzymes hydrolyze food particles to break larger molecules into smaller ones
Some nutrients are absorbed without digestion
Vitamins, minerals, cholesterol, water

6. Anatomy of the Digestive System
Oral Cavity
Pharynx
Esophagus
Stomach
Small Intestine
Large Intestine

7. Small Intestine 6 meters in length Functions: Chemical Digestion
Nutrient Absorption
Nutrient Transportation

8. Functions of the Small Intestine
Digestion and absorption of food
Digestive enzymes secreted by the pancreas
Enter the small intestine via the pancreatic duct.

9. Anatomy of the Small Intestine
Duodenum (25 cm)
Food mixes with bile from the gallbladder.
Jejunum (2.5m)
Absorbs nutrients into the bloodstream.
Ileum (3.6 m)
Reabsorbs bile acids.

10. Large Intestine 1.5 meters long
Responsible for absorption of water from the indigestible residue of food

11. Anatomy of the Large Intestine
Ascending Colon: Descending Colon: Up the right side Down the left side Cecum: Sac on Sigmoid Colon: lower right side S-shaped

12. Anatomy of the Large Intestine
Ascending Colon-Removes water and other nutrients
Transverse Colon-Expulsion of waste materials, continues leaching out
Descending Colon-Absorbs water from fecal matter. Stores food particles that are to be emptied into the rectum.
Sigmoid Colon- Make and eliminate feces. Contains 60 varieties of bacteria
Rectum- Temporary storage for fecal matter before it’s eliminated from the body through the anal canal.

13. Oral Cavity Functions:
A. Ingestion: Cheeks lips and tongue mobilize food
B. Digestion:
Mechanical
Mastication
Chemical
3 salivary glands
Digests some starches and fat

14. Pharynx
Purpose: Pharyngeal constrictors force food down during swallowing
Divided into 3 parts:
Epipharynx
Mesopharynx
Hypopharynx

15. Esophagus Straight Muscular tube about 1 foot long
Purpose: Muscular contraction moves food towards stomach

16. Stomach Food storage Mechanical digestion Chemical digestion
Muscular sac on the left side of the peritoneal cavity
Functions:
Food storage
Mechanical digestion
Chemical digestion

17. Enzymes Involved in Chemical Digestion
Saliva:
Amylase: Breaks down starch
Lipase: Breaks down fats when it enters the stomach
Stomach:
HCL: Activates enzymes, breaks up foods
Pepsin: Digests proteins
Renin: Digests milk

18. Final Destinations of Digestion Products
Starches  bloodstream
Fats  lymph vessels (lacteals)
Proteins  bloodstream