1. Comparative Digestive Systems Topic 3024
Amanda Moore
Torey Birchmeier
Modified by
Ashlee Gibson

2. Digestive Systems Overviews

3. Digestion
Digestion: Breaking down large, nutrient macromolecules into simpler molecules for use by an organism.
Food enters the mouth and goes through mechanical and chemical changes as it passes through the alimentary canal.

4. Types of Stomachs Simple Stomach Complex Stomach
Man, Pig
Complex Stomach
Cattle, Sheep, Goats
Simple Stomach with enlarged ceacum
Horses, Rabbits, Guinea Pigs

5. Parts of Digestive Tract
Mouth: initial opening of alimentary canal
Salivary Glands
secrete juices that contain enzymes to help break up the food
Mastication
chewing, crushing, preparing food for swallowing

6. Parts of Digestive Tract
Pharynx: funnel shaped muscle between mouth and esophagus
part of digestive and respiratory tracts
Esophagus: muscular tube connecting pharnyx to stomach
muscle contractions move food down to stomach

7. Parts of Digestive Tract
Stomach: located between esophagus and small intestine
Two basics types
Simple
Ruminant

8. Parts of Digestive Tract
Simple Stomach
Humans, swine, rabbits and horses
Divided into three regions
cardiac
fundus
pylorus

9. Simple Stomach Digestion: is mechanical, muscle contractions
is chemical, enzymes soften and break down macromolecules of food
enzymes are catalysts, they start the chemical reactions

10. Simple Stomach Enzymes that break down food
Gastric-break down proteins in stomach
Liver and pancreatic-break down fats in small intestine
Intestinal-break down carbohydrates and proteins in small intestine

11. Parts of Digestion Tract
Ruminant Stomach
Sheep, Cows and Goats
Occupies 3/4 of the abdominal cavity

12. Four Components of Ruminant Stomach
Rumen
composes 80% of ruminant stomach in mature bovine animals and 30% in young animals
Reticulum
composes about 5% of bovine stomach
prevents indigestible objects from entering the stomach

13. Four Components of Ruminant Stomach
Omasum
composes 7-8% of bovine stomach
absorbs mostly water
Abomasum
the “true” stomach
composes 7-8% of stomach in mature animals and 70% in young animals

15. Digestion in the Ruminant Stomach
Rumination: The process of regurgitation, re-mastication, re-salivation and re-swallowing of food.
Purpose: To smash and break up food which provides more surface area bacteria to break down

16. Parts of Digestive Tract
Small Intestine: long, coiled tube connecting the stomach with the large intestine.
Is covered by villi which increases surface area to increase absorption
Food moves through by muscle contractions called peristaltic movement
Final breakdown and absorption of nutrients occurs here

17. Parts of the Digestive Tract
Large Intestine
Includes cecum, colon and rectum
Absorbs water
Very little nutrient absorption takes place here

18. Parts of the Digestive Tract
Accessory Organs
Pancreas
produces and secretes digestive enzymes
produces insulin which regulates carbohydrate metabolism
Liver
produces bile-breaks down fatty acids
stores iron, handles fats and carbohydrates in the blood