The document summarizes the digestive systems of various animals. Carnivores like dogs and cats eat meat, herbivores like cattle eat plants, and omnivores like pigs and humans eat both plants and animals. Herbivores have complex multi-chambered stomachs like cows that allow them to digest cellulose, while carnivores and omnivores have simpler single-chambered stomachs. The document then describes the specific structures and functions of the digestive tract in cows, horses, chickens, and humans.

2. 1. Carnivores – eat meat – dogs and cats
2. Herbivores – eat plants - cattle, horses,
and sheep
3. Omnivores – both plant and animal
eaters – pig and humans

3.  Monogastric – 1 stomach – can’t digest
cellulose (fiber) – pigs and humans
 Ruminant – 4 stomachs – polygastric – digest
cellulose, produce own B vitamins and proteins
– cows and sheep
 Pseudo-ruminant - have 1 stomach, but have
enlarged cecum that digests cellulose – horses
and rabbits

6.  Prehension – gathering food –
teeth, lips, tongue
 Mastication – Chewing – break food into
smaller pieces for swallowing – teeth and
saliva

7.  Esophagus – transport tube to stomach –
muscular contractions move food down

8.  Stomach
 conditions – pH of
2, churning and
contracting to mix
and grind food
 ingredients –
food, HCl, enzymes

9.  Small intestine
 major site of nutrient absorption
 Functions – villi absorb nutrients that have been
broken down – minerals, vitamins,
amino acids,
Fatty acids,
simple sugars

10.  Glands –
gallbladder secretes
bile used for lipid
breakdown;
Pancreas secretes
enzymes for protein
and carbohydrate
breakdown

11.  Large intestine – colon
 accumulates wastes
 absorbs water
 Rectum and Anus

14.  Mouth
 Prehension – cow tongue is very long
 Mastication – graze rapidly, and don’t
chew much 1st time
 Esophagus – liquids to the reticulum and
solids to the rumen
 Rumen – very large compartment

15. Regurgitation – when rumen full, force contents
back up to re-chew
 Rumination
 re-mastication of cud or bolus
 Bolus – ball of grass
 Adds saliva to food
 Esophagus – re-swallow food
 Reticulum – honeycomb

16. – fermentation vat
 30 gal or more
 contains microbes that break down the
cellulose
 pH of 6.5 – 7 for microbes
 releases methane – belch
 creates B vitamins and proteins from
amino acids
 also contains papalli that absorb
nutrients released by microbes

17.  Omasum – filter for large particles – grinds
them down
 Abomasum – like the monogastric stomach –
acidic
 Small intestine – same as monogastric
 Large intestine – same as monogastric
 Rectum and anus

18. Omasum Abomasum
Rumen Reticulum

19. Rumen
Large
intestine Omasum
Rectum
Anus
Cecum Abomasum Reticulum
Small intestine

21. Small
colon Large
colon
Rectum
Esophagus
Anus
Cecum
Small
intesine

22. Mouth
 a. prehension
 b. mastication
Esophagus
Stomach
 a. same as monogastric
 b. too small in horses and inactive
– doesn’t break down cellulose
 c. require frequent smaller meals

23.  Small intestine – absorption of nutrients – same
as monogastric
 **Still has not digested the cellulose – large
amount
 Cecum
 enlarged area between small and large
intestine
 contains microbes that break down cellulose
like rumen

24.  Large colon – absorbs nutrients released by
cecum
 Small colon – absorbs water and collects waste
 Rectum and Anus

27.  Beak
 Prehension – claws
 Mastication - no teeth and no enzymes
in the saliva
 Esophagus
 Crop – enlargement in esophagus that adds
moisture
 Proventriculus – adds HCl and enzymes to
begin digestion

28.  Gizzard – muscular region that contains grit to
grind food
 Small intestine – absorbs nutrients through
villa
 Ceca – bi-lobed region that breaks down and
absorbs cellulose – not much in chicken diet
 Large intestine – very short – absorbs water
 Cloaca – urine is combined with feces – very
high in N
 Vent – homologous to the anus