Digestive System

alimentary canal

which extends from the mouth to the anus

monogastric

digestive system of the dog is described as such

The accessory glands include the: Salivary gland Liver and gall bladder Pancreas

Oral cavity

extends from the lips to the entrance of the pharynx.

Oral vestibule

space between the lips and the teeth

Labial vestibule

between lips and incisors

Buccal vestibule

between lips and cheek teeth

Proper oral cavity

bounded rostrally by the lips, laterally by the cheeks, dorsally by the hard palate and ventrally by the tongue

Diastema or physiologic gap

large communication space between the vestibule and proper oral cavity. Located between the canine tooth and premolars in dogs.

Lips

form the rostral and most of the lateral external boundaries of the vestibule. The upper and lower _____ meet at the angle of the mouth. In dogs, upper ____ is pendulous and presses on the lower one. The general looseness of the _____ creates a large vestibule- an advantage in administering liquid medicines.

Cheek

forms the caudal portion of the lateral walls of the vestibule. In dogs are small because of the large mouth opening.

Hard palate

represents the osseous part (processes of the palatine, maxilla and incisive bones) and the mucosa that covers its oral surface. There are 6 to 10 palatine rugae that transversely cross the oral cavity.

4th cheek tooth

The hard palate is widest at the _______ and median raphé usually replaced by a ridge.

Soft palate

direct continuation of the hard palate. Particularly long in dog thus pose a difficulty in breathing in brachycephalic breeds.

Incisive papilla

a rounded eminence located just caudal to the upper central incisor. On each side of this papilla is the orifice of the incisive duct which communicates with the vomeronasal organ (Jacobson’s organ)

Teeth

highly specialized structures that serve for the procuring, cutting, and crushing of food as well as for social interaction. They are arranged in two dental arcades, one associated with the mandible and one with the incisive and maxillary bones.

Root

portion of the teeth which is covered with cement and is embedded in the gum through the socket of bone called an alveolus by periodontium (periodontal membrane) making up a specialized joint termed as gomphosis.

Crown

the part of the tooth visible above the mucous membrane of the gum. It is the portion of the tooth covered with enamel.

Neck

the line junction of crown and root.

Dentin

comprises the bulk of the tooth and contains the dental cavity in the center. constitutes the ivory of elephant tusks.

odontoblasts.

Dentin is produced by the ___________.

dental pulp

a mass of delicate connective tissue, blood vessels and nerves found in the center of the dental cavity.

Enamel

hardest part of the tooth and the hardest part of the body; brilliant white in color.

ameloblast

Enamel is produce by ____________.

hypsodonts

In _________, it covers also the embedded crown but not the short roots.

brachydonts

In __________, enamel covers only the crown white.

Cementum

thin, bonelike layer on the surface of the teeth. Holds the tooth firmly in the gum. Found only in the root in dogs

Dental pulp

soft tissue contained in the root. Composed of sensory nerve, arteries, veins, lymphatic capillaries and connective tissues. They are contained in the pulp cavity

pulp cavity

contains the dental pulp

Vestibular surface

surface of teeth that faces the lip or cheek, formerly called labial or buccal surface.

Lingual surface

surface of the teeth that faces the tongue

Contact surface

surface of the teeth that faces the adjacent teeth in the dental arch.

distal surface

the contact surface adjacent to the next caudal or lateral tooth.

Mesial surface

the contact surface adjacent to the next rostral or medial tooth

Occlusal surface

surface that faces the ipsilateral opposite upper and lower arch

Incisors

teeth embedded in the incisive bone and mandible. It is composed of central ______ (I1), middle _________ (I2) and lateral ________ (I3). Also known as nippers.

Canines

robust, long, pointed and slightly curved in dogs. It is the longest teeth in dogs with roots nearly two times as long as their crown. Also known as eyeteeth, bridle teeth, holding teeth, tusks, or tushes.

Premolars and Molars

teeth caudal to the canine are as the cheek teeth. They are grinding teeth forming the sides of the dental arch.

carnassial teeth or sectorial teeth

Upper 4th premolar and 1st lower molar teeth are the largest teeth and are referred to as _________________ (with 3 roots).

Molars

found only in permanent dentition

Premolars

are anterior to the molars

Temporary dentition

2 (I 3/3 C 1/1 P 3/3 M 0/0) = 28

Permanent dentition

2 (I 3/3 C 1/1 P 4/4 M 2/3) = 42

Tongue

It is divided into a free apex at the rostral end, a meaty body, and a caudal root adjacent to the pharynx. The entire _______ is mobile through its muscular attachments to the hyoid apparatus and mandible.

Lingual frenulum

unpaired, median mucosal fold at the ventrum of the tongue to connecting the tongue to the floor of the mouth.

dorsum of tongue

covered with papillae.

gustatory papillae

are covered in taste buds

mechanical papillae

cornified and aid in licking while protecting deeper structures

Filiform papillae

smallest and most numerous; located at the rostral 2/3 of the tongue. Looks like hair; are long and soft

Conical papillae

bigger but less frequent, found at the dorsum of the caudal 1/3 of the tongue. Each stands on a wide circular base and a pointed apex.

Marginal papillae

present in rostral half of the tongue of new-born carnivores and piglets that aids in suckling milk; disappears when the diet changed to solid

Fungiform papillae

looks like tiny mushroom at the rostral 2/3 of the tongue; scattered together with the filiform and can also be considered as mechanical

Foliate papillae

series of leaf-shaped ridges separated by crypts; located at the dorsolateral border of the caudal 1/3 of the tongue immediately rostral to the palatoglossal arch

Vallate papillae

with circular projections; largest and least numerous; located on the dorsum at the caudal third of the tongue, surrounded by a circular cleft and do not project above the surface of the tongue; there are 3 to 6 in dogs, common is 4

Lyssa

bar of cartilage embedded in the ventral surface of the apex of tongue of dog.

Salivary Glands

Composed of all glands that pour their secretions into the oral cavity. They include both major and minor.

Parotid gland

lies at the junction of the head and neck overlying at the basal portion of the auricular cartilage. The gland is dark-flesh in color with course lobulations.

Sublingual gland

there are two sublingual glands: monostomatic and polystomatic. In monostomatic sublingual gland, all the secretions enter the oral cavity via one opening, the sublingual caruncle located adjacent to the rostral lingual frenulum. The polystomatic sublingual gland is composed of 6 to 12 lobes and release their secretion by several ducts.

Mandibular gland

ovoid body lying largely between the linguofacial and maxillary veins just caudal to the angle of the mandible

Zygomatic gland or orbital gland

located ventromedial to the zygomatic arch. It is globar to pyramidal in shape. Found only in dogs and cats. It represents a caudal condensation of the largely unilobulated dorsal buccal glands of other mammals

The minor salivary glands include labial, buccal, molar, lingual and palatine

pharynx

a passage common to both the respiratory and the digestive systems. It is a musculomembranous junction of the respiratory and digestive tubes between the oral and nasal cavities rostrally and the esophagus and larynx caudally. It is consisting of nasal, oral, and laryngeal parts

Nasopharynx

dorsal to the soft palate; respiratory channel

Oropharynx

ventral to the soft palate; digestive channel

Laryngopharynx

part where the air from nasopharynx crosses to reach the larynx and the food and water from the oropharynx crosses into the esophagus thus it is considered as both respiratory and digestive channel

Pyriform recess

continuation of the floor of oropharynx on either side of the larynx. This is the site in dogs where the bones may become lodge and close the laryngeal opening of the airway

Pharyngeal opening or isthmus of fauces

the opening from the oral cavity to the oropharynx

Caudal nares or choana

the osseous opening between the caudal nasal cavity and nasopharynx

Pharyngeal openings of the auditory tubes

the slits in the lateral walls of the nasopharynx leading to the middle ear.

Laryngeal opening (aditus laryngeus)

- the opening to the larynx surrounded by rostral laryngeal cartilage

Esophageal opening (aditus esophagi)

the opening at the caudal end of the laryngopharynx into the esophagus.

Esophagus

the first part of the alimentary canal. It is a connecting tube between the laryngeal part of the pharynx and the stomach. In medium-sized dogs it is approximately 30 cm long and 2 cm in diameter when it is collapsed.

Cricopharyngeus muscle

cranial end acting as a sphincter

Cardiac sphincter

caudal end, part of the stomach acting as a sphincter

Stomach

Largest dilation of the gastrointestinal tract caudal to the esophagus. It is a musculoglandular organ interposed between the esophagus and the small intestine. It varies greatly in size. It stores and partly mixes the food, and its intrinsic glands intermittently add enzymes, mucus, and hydrochloric acid.

Greater curvature

long, convex surface of the stomach extending from the cardia to the pylorus. Greater omentum (epiploon) is attached to this structure.

Lesser curvature

short, concave surface of the stomach extending from cardia to pylorus. It is the attachment site of the lesser omentum.

Parietal surface

side in contact with the liver

Visceral surface

side in contact with the other abdominal organs

Cardia or cadiac ostium

opening of the esophagus into the stomach

Fundus

blind expanded part of the stomach at the left side above the level of the cardia

Body

largest part of the stomach

Pylorus

distal opening of the stomach

Pyloric part

portion of the stomach distal to the body

Pyloric antrum

wide proximal part of the pyloric part

Pyloric canal

narrow distal passage surrounded by the pyloric sphincter.

Pyloric sphincter

functional sphincter at the distal end

Gastric folds or rugae

internal folds of the stomach mucosa to increase the surface area.

Small intestine

extends from the pylorus of the stomach to the ileocolic orifce leading into the large intestine. It is the longest portion of the alimentary canal, having an average length, in the living animal, of 3.5 times the length of the body. It is divided into duodenum, jejunum and ileum.

Duodenum

first of three divisions of the small intestine. It is closely attached to the right side of the dorsal body wall by a short mesentery, the mesoduodenum . It has a descending, transverse and ascending portion.

Cranial flexure

separates descending duodenum from the pyloric end of the stomach

Caudal flexure

separates the descending duodenum from the ascending duodenum

Duodenojejunal flexure

separates the ascending duodenum from the jejunum

Jejunum

the longest and most movable part of the small intestine. It is attached to the body wall by the mesojejunum. The mesojejunum and mesoileum are often collectively referred to as the great mesentery.

great mesentery.

The mesojejunum and mesoileum are often collectively referred to as the ___________—

Ileum - is the short terminal part of the small intestine. The distinction between the ileum and jejunum is defined by the proximal extent of the ileocecal folds. Take note that the ileum is more muscular and firmer than the jejunum. It terminates at the cecocolic junction of the large intestine forming the ileal orifice

Large Intestine

short and unspecialized. The __________ of the dog is much simpler than that of the other domestic animals. Neither haustra nor tenia exists; nor are flexures or spirals present. In general, it is a simple tube, only slightly larger in diameter than the small intestine. Its most important function is the dehydration of its fecal contents. divided into cecum, colon, rectum, and anal canal. It begins at the ileal papilla and ends at the anus.

Cecum

commonly described as the first part of the large intestine, but this is not true in dogs as the ileum communicates with the ascending colon. The cecum exists as a diverticulum of the ascending colon. The _____ of dog is spiral S-shaped. It a blind pouch with a tapering apex, a body and a base. It is located on the right side of the abdominal cavity in the dog. It has the communication with the ascending colon via the cecocolic orifice.

Colon

divided into ascending, transverse, and descending segments and their connecting flexures. lies in the dorsal part of the abdominal cavity and is shaped like a shepherd’s crook or question mark. held by the mesocolon.

Right colic flexure

separates ascending and transverse colon