The digestive system converts food into nutrients through a long tube called the alimentary canal or gastrointestinal tract. It begins at the mouth and ends at the anus. The main parts include the mouth, esophagus, stomach, small intestine, large intestine, and exocrine glands like the pancreas and liver. In ruminants, the stomach is compound with four chambers, while in non-ruminants it is simple. The mouth contains the tongue, teeth, and three pairs of salivary glands that produce enzymes to begin breaking down food.

1. Veterinary Anatomy-II Digestive System
1
(Lecture-1)
By Sir Saleem Qaiser
The digestive system is a group of organs working together to convert food into energy and basic
nutrients to feed the entire body. Food passes through a long tube inside the body known as the
alimentary canal or the gastrointestinal tract (GI tract). In all the animals digestive tube starts from
mouth and ends at Anus. The digestive tube under the considerable modifications in its various
parts, to accomplish such specialized functions:-
- Chewing
- Swallowing
- Digestion
- Absorption
- Excretion
PARTS OF DIGESTIVE SYSTEM:-
Sr.
#
PARTS It includes SUB-PARTS
1.
Exocrine
Glands
Pancreas -
Liver -
Salivary Glands
Parotid
Sublingual
Submandibular (Sub
maxillary)
2.
Alimentary
Canal
Mouth
Tongue
Teeth
Pharynx
Esophagus -
Stomach
Simple Stomach (Non-
Ruminant)
Compound Stomach
(Ruminant)
Small Intestine
Duodenum
Jejunum
Ileum
Large Intestine
Caecum
Large Colon
Small Colon
Rectum
Anus

2. Veterinary Anatomy-II Digestive System
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STOMACH
 SIMPLE STOMACH:-
It is the stomach of Non- Ruminants or Mono-gastric Animals (Horse, Dog, cat, Human) and it
has four regions:-
- Cardiac = Esophagus enters stomach through this region
- Fundic = It is the upper region of stomach next to the cardiac region.
- Esophageal
- Pyloric = Stomach ends and Duodenum starts from this region.
 COMPOUND STOMACH:-
It is the stomach of the ruminants or poly-gastric animals
(Cattle, sheep, cow, goat). It consists of four chambers:-
- Rumen (largest chamber)
- Reticulum (honeycomb like interior)
- Omasum (numerous folds in its interior)
- Abomasum (True Stomach)
MOUTH
Mouth is the first part of the digestive system. It includes lips, tongue, teeth and salivary glands. It is
responsible for the initial breakdown of the food material by
the chemical action so, that the smaller particles may be
more readily acted upon by digestive juices.
BOUNDRIES OF MOUTH:-
 Rostral boundary = Lips
 Dorsal Boundary = Hard palate and Soft Palate
 Lateral Boundary = Cheeks
 Ventral boundary = tongue
 TONGUE
Tongue is a muscular organ and it consists of a mass of muscles which are covered with mucus
membrane. Tongue has three different kinds of muscles:-
 Hyoglossus muscle = It attaches basihyoid bone.
 Geneoglossus muscle = It attaches symphysis
mandibulae.
 Styloglossus muscle = It attaches the inside of the
stylohyoid bone.
Cattle use the tongue as a pre-
hensile organ responsible for pre-
hension.

3. Veterinary Anatomy-II Digestive System
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TONGUE PAPILLAE:-
Tongue consists of Stratified Squamous Keratinized epithelium that presents the large number
of papillae:-
- Filiform Papillae
- Fungiform Papillae
- Foliate Papillae
- Vallate Papillae (Cicumvallate papillae)
- Lenticular papillae
 Filiform Papillae are smallest hair like in
appearance. In the OX they consist of the
connective tissue and are covered by highly
qualified epithelial layer. In case of horse they
are shorter and softer.
 Some glands are also formed in the foliate
papillae of the horse and dog.
 Vallate papillae are larger and circular projections which are surrounded by deep grooves.
They also contain taste buds and serous glands in all domestic animals. They also contain
mucous glands in case of horse. They are also called as circumvallate papillae.
 Vallate and Fungiform papillae have taste-buds
while filiform, foliate, and lenticular papillae do
not contain any taste buds.
 PALATE
The roof of the mouth, separating the cavities of the mouth and nose is called palate. They are of
two types:-
- Hard Palate: It is a wide and is usually more or
less pigmented. Its body is covered by dense
connective tissues. Their number is 15-19 and
is usually straight.
- Soft Palate: It is situated behind the hard
palate and is comparatively shorter than had
palate.
MEMORY AID: FFFVL
Taste buds may also be formed on
the epiglottis, larynx, pharynx and
soft palate.

4. Veterinary Anatomy-II Digestive System
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 SALIVARY GLANDS
The salivary glands are exocrine glands that produce saliva. They also secrete amylase, a
digestive enzyme that breaks down starch into maltose and glucose. There are three types of
Salivary glands:-
 PAROTID GLANDS: They are situated below the ears
and behind the angle of the jaws and they produce
serous secretions into the mouth via parotid ducts.
 SUBLINGUAL GLANDS: They are located beneath the
mucus membrane of the mouth on each side of the
tongue or they are located beneath the tongue. They
produce mix type of secretions (serous + mucous)
which empties via a number of sublingual ducts (deep
ducts which are 30 in case of horse and they open along
the sublingual fold of the tongue into the oral cavity).
 SUBMAXILLARY (Sub Mandibular glands): They are
located medial to the parotid glands and in some species they may be covered by the ramus
of the mandible. They also produce mix type of secretions (serous + mucous).
 TEETH
They develop from the invagination of the epithelium which is called as dental lamina. It
produces enamel which is a cap like covering of the connective tissue and is called as dental
papillae. The teeth are of four different types:-
1. Incisor
2. Canine
3. Pre-Molars
4. Molars
 PHARYNX:-
It is a funnel shaped musculo-membranous organ which belongs both through the digestive and
respiratory system. The pharynx has seven openings:-
- Posterior Nares (2)
- Eustachian tube (2)
- Oral Opening (1)
- Laryngeal Opening (1)
- Esophageal Opening (1)
The canine teeth may also be called as
eye teeth, bridal teeth, tusk and tushes.