Digestivepowerpoint comparative anatomy.ppt

Digestive system of animals

1. Digestive Systems

2. Digestive Systems Overviews
Objectives
•Describe the structures and functions of
the digestive system of ruminant
animals
•Draw the structures of the digestive
system of ruminant animals
•Label the structures of the digestive
system of ruminant animals

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
–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
–secretes enzymes which breakdown fat and
starches
•Liver
–secrets bile which digest fats

19. The Digestion Process

20. The Digestion Process
•Food is broken down
•Animals have digestive systems adapted to the
foods that they consume
•Four types of digestive systems
–Ruminant(polygstric)
–Simple Stomach(monogastric)
–Avian
–Equine-modified simple stomach

21. Ruminant Digestive System
Modified to handle the breakdown of
large amounts of fiber

22. Ruminant Digestive System
•Mouth
–no upper incisors, hard palate
–molars for grinding coarse vegetation
–saliva does not contain enzymes
•Esophagus
–muscular tube connecting the mouth to the
stomach

23. Ruminant Digestive Systems
The Four Compartmented Stomach
•Rumen: storage area and fermentation vat
•Reticulum: nails and wire may be found
here-hardware stomach
•Omasum: eliminates excess water from feed
•Abomasum: true stomach, gastric juices
and enzymes are secreted

24. Ruminant Digestive Systems
Stomach (cont.)
•Regurgitation: first step in rumination
–large quantities of roughage are consumed and
are chewed just enough to swallow
–after swallowing, regurgitation (“cud chewing”)
takes place, food is re-chewed

25. Ruminant Digestive System
•Small Intestine
–connects stomach to large intestine
–food nutrients absorbed into blood
–contains bile and pancreatic juices
–pushes food through by muscle contractions

26. Ruminant Digestive System
•Large Intestine
–Contains Cecum, Colon and Rectum
•Cecum: sac at junction of small intestine and large
intestine
•Colon and rectum: at end of system
–not as long as small intestine, but larger in
diameter
–water and some nutrient absorption occurs here
–where residue solidifies before excretion

27. Monogastric Digestive System
Characterized by inability to digest
roughage efficiently

28. Objectives
•Describe the structures and functions of the
digestive system of non-ruminant animas
•Draw the structures of the digestive system
of non-ruminant animals
•Label the structure of the digestive system
of non-ruminant animals

29. Monogastric Digestive System
•Mouth
–has upper and lower incisors
–digestive enzymes secreted which breaks down
nutrients
•Esophagus
–connects mouth to stomach

30. Monogastric Digestive System
•Stomach
–secretes Hydrochloric Acid to break down
nutrients
–enzymes such as pepsin also secreted here
–churning action mixes food
–small and large intestine
•function just as in ruminant systems

32. Avian Digestive Systems
Characterized by several organs not
found in other species that are
adapted for grinding hard or encased
food

33. Avian Digestive Systems
•Mouth
–no teeth which leads to the saying “scarce as a
hen’s teeth!!”
–Salivation excretion moistens food
•Esophagus
–has a modification called the “crop” which
stores and moistens food
–connects mouth and stomach

34. Avian Digestive Systems
•Stomach
–Contains two parts
•Proventriculus: same as monogastric stomach and
provides digestive excretions
•Gizzard: located after proventriculus, very
muscular, used to grind food

35. Avian Digestive Systems
•Small Intestine
–similar functions as in ruminants and monogastric
systems
•Large Intestine
–similar functions as in ruminants and monogastric
systems
–“cloaca”: chamber into which urinary and genital
canals open
–“ceca”: aids in fiber digestion and absorption

37. Equine Digestive Systems
Characterized by non-ruminant
animals that consume and digest
feeds high in fiber

38. Equine Digestive Systems
•Mouth
–intact top and bottom incisors
–molars adapted to chewing fibrous feeds
–no digestive enzymes in saliva
•Esophagus
–not well adapted for regurgitation
–connects mouth and stomach

39. Equine Digestive System
•Stomach
–similar to monogastric system
•Small intestine
–similar to monogastric and ruminant systems
–no gall bladder to store bile
–enlarged cecum to aid in fiber breakdown

40. Equine Digestive System
•Large Intestine
–similar to monogastric systems
–cecum (at junction of small and large intestines)
and colon take up most of the volume of the
equine digestive system

42. Accessory Organs
Organs that aid in the digestive
process without actually being part of
the digestive system

43. 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

44. The End!!