Splanchnology

Gums (Gingiva)

composed of dense fibrous tissue covered by smooth, heavily vascularized mucosa

Gums (Gingiva)

It is the part of the mucosa that is intimately united to the periosteum of the alveolar processes of the jaw.

Gums (Gingiva)

It extends from the neck of the teeth and down into the alveoli.

Gums (Gingiva)

They are continuous externally with the mucosa of the vestibule, and internally with that of the floor of the oral cavity proper or of the hard palate.

Tongue (Lingua)

It fills the oral cavity when the upper and lower teeth are in contact. It is supported caudally by the hyoid bone.

Tongue (Lingua)

It is composed primarily of skeletal (striated) muscle, adipose tissue, some glands, and externally of a thick mucous membrane.

Tongue (Lingua)

It extends from its attachment on the basihyoid bone to its free tip at the mandibular symphysis.

Sorting of food, intake of liquid, sucking on the newborn, tactile organ, chemical selection of food (taste buds), grooming and getting insects, heat dissipation

functions of the tongue

dorsum liguae, margin of the tongue, apex, body, root

parts of the tongue

dorsum linguae

the surface of the tongue opposite to the palate where the wear of the tongue is the greatest.

lingual mucosa and median groove

parts of the dorsum linguae

lingual mucosa

It is rough compared to the ventral surface due to the presence of lingual papillae.

Median groove

divides the dorsum linguae into two lateral halves, extending from the tip of the tongue to the level of the caudal pair of vallate papillae.

margin of the tongue (margo linguae)

separates the dorsal and ventral surfaces of the tongue.

apex

free rostral portion of the tongue; the thinnest and narrowest end of this muscular organ formed by the rostral formation of the two margins.

lyssa

a median filiform structure embedded in the musculature along the ventral surface of the apex.

body (corpus linguae)

caudal to the apex and represents the bulk of the tongue; it is long and slender.

root (radix linguae)

the caudal one-third, sloping ventrally toward the base of the epiglottis.

lingual frenulum

an unpaired, median mucosal fold on the ventral surface of the tongue which primarily connects the body of the tongue to the floor of the mouth.

Fimbriated plica

a rounded fold of mucosa protruding on each side of the lingual frenulum on the ventral surface of the tongue.

Sublingual vein

can be used for venipuncture, located between the lingual frenulum and the lateral border of the fimbriated plica.

Trigeminal (V), Facial (VII), Glossopharyngeal (IX), Vagus (X)

The sensory nerve of the tongue that is for pain, temperature, tactile and touch and taste (gustatory)

Hypoglossal (XII)

the only motor nerve of the tongue

lingual papillae

filiform and conical function in mechanical; fungiform, vallate, and foliate function mainly for gustatory.

filiform, fungiform, vallate, foliate, conical, and marginal papillae

types of papillae

filiform papillae

are the smallest in size and the most numerous of all lingual papillae; soft, thorny serrations giving the mucosa a velvety appearance.

filiform papillae

Located in the dorsum of the rostral two-thirds of the tongue, composed of primary, secondary and tertiary filiforms.

8-10

how many filiform papillae surround a single fungiform papillae?

fungiform papillae

are mushroom-shaped papillae on the rostral two-thirds of the tongue; larger, broader but shorter and less numerous than filiform papillae and gustatory (contain taste buds).

fungiform papillae

Second most numerous and are most concentrated at the tip and sides of the tongue.

fungiform papillae

The blood they contain gives them a dark pink appearance making them prominent.

vallate papillae

are located on the caudal third of the dorsum of the tongue; and mark the boundary between the filiform papillae of the oral part and the conical papillae of the pharyngeal part of the tongue.

Serous gustatory glands or von Ebner’s gland

exists at the base of the vallate papillae; associated with the ducts of these glands are lymphoid aggregates.

foliate papillae

two groups in the dog, each located on the dorsolateral aspect of the caudal third of the tongue rostral to the palatoglossal arch.

conical papillae

found on the dorsum of the caudal one-third of the tongue

conical papillae

Each stands on a wide circular base and narrows to a thin, hard point at its apex.

conical papillae

Are mechanical and tactile

marginal papillae

threadlike and narrower, function in suckling, and are present in newborn dogs; they disappear as the pups change from liquid to solid diets.

Premolar carrying space

is the area of lack of occlusal contact which extends from the canine teeth to the third premolars.

taste buds

is a pear-shaped group of epithelial cells located in the gustatory papillae: fungiform, vallate, and foliate papillae.

taste buds

They are broad basally and narrow apically where they communicate with the oral cavity through an apical taste pore.

dark or type I cell, light or type II cell, type III cell, and basal cell

four types of cells

type III cell

a cell that is involved in the transmission of stimulus to the sensory nerves that serve the taste buds.

sweet-taste, salt-taste, and sour-taste sensitivity

map of qualities of taste sensitive fibers

sweet-taste sensitivity

a sensitivity that is at the rostral margins and tip of the tongue

salt-taste sensitivity

a sensitivity that lies within the distribution of the chorda tympani (Facial nerve)

sour-taste sensitivity

a sensitivity that is almost evenly distributed over the dorsum of the tongue

fungiform area and areas innervated by chorda tympani

sensitive to sweetness, sourness and saltiness.

Areas innervated by glossopharyngeal

insensitive to sweet and salt tastes

The tip of dog’s tongue

is also sensitive to water taste

saliva

can be serous or mucous in character, which helps in the formation of bolus and acts as a lubricant during swallowing.

parotid, sublingual, mandibular and zygomatic

Major salivary glands

minor salivary glands

these are the glands inside the oral cavity: labial, buccal, lingual and palatine

parotid gland

It lies at the junction of the head and neck overlying the basal portion of the auricular cartilage.

parotid gland

Its outline is V-shaped as viewed from the surface with the apex directed ventrally.

parotid gland

It is unencapsulated, lobular, and lighter red than the adjacent skeletal muscle and fills more or less the retromandibular fossa.

parotid duct

It is formed by two or three converging radicles which leave the ventral third of the rostral border of the gland and unite with each other on the masseter muscles.

parotid duct

It is related to the lateral surface of the masseter as it runs straight forward to the cheek, parallel, or nearly parallel, to the fibers of the muscle.

parotid duct

It opens into the buccal cavity at the rostral end of a blunt ridge of mucosa by a small papilla located opposite the caudal margin of upper P4.

Accessory Parotid Glands

usually are present on one or both sides, lying above the parotid duct.

Parotid artery

a branch of external carotid artery; it is the main blood supply in the parotid gland. Other supply comes from: caudal auricular, masseter, transverse facial and rostral auricular arteries.

mandibular gland

The encapsulated, round or oval gland lying largely between the external and internal maxillary veins just caudal to the angle of the jaw

Mandibular Duct

It leaves the medial surface of the gland near the ventromedial part of the impression formed by the sublingual gland.

Mandibular Duct

The duct lies between the masseter muscle and mandible laterally, and the digastricus medially.

mandibular duct

The remaining part is closely related to the sublingual duct and opens on the sublingual caruncle on the floor of the oral cavity.

facial artery

the largest artery supplying the mandibular gland; it enters the gland where the mandibular duct leaves.

lingual vein

the chief vein draining the gland.

sublingual gland

It is the smallest of the four pairs of major salivary glands, lying under the mucosa of the lateral sublingual recess and of the lateral surface of the tongue.

orbital gland

zygomatic gland is also known as?

zygomatic gland

It is globular to pyramidal in shape.

It has one major duct and four minor ducts.

The major duct opens on the ridge of mucosa that extends to a plane through the caudal surface of the last upper cheek tooth.

The smaller, minor ducts open on this ridge, caudal to the opening of the major duct.

Infraorbital artery

supplies the zygomatic gland

pharynx

It is the common passageway for food and air.

pharynx

It extends from a transverse plane through the head at the level of orbital openings to a similar plane through the second cervical vertebrae.

nasopharynx, oropharynx, and laryngopharynx

parts of the pharynx or divisions of the pharynx

Paired choanae, Paired pharyngeal openings of the auditory (Eustachian) tube, isthmus faucium, aditus larynges, and entrance of the esophagus

The pharyngeal cavity has the following openings:

paired choanae

an opening at the pharyngeal cavity that is rostrodorsally, they connect the nasopharynx with the nasal cavity.

Paired pharyngeal openings of the auditory (Eustachian) tube

these openings connect the nasopharynx with the middle ear cavities

Isthmus faucium

an opening that is slit-like, leading from the oral cavity into the oropharynx; bounded laterally by the palatoglossal arches, dorsally by the soft palate, and ventrally by the root of the tongue.

Aditus larynges

these openings are caudoventrally, when the animal swallows, the aditus is closed by the epiglottis.

Entrance to the esophagus

at the caudal end of the laryngopharynx.

nasopharynx

is part of the respiratory channel. It lies dorsal to the soft palate and extends from the choanae to the intrapharyngeal opening (pharyngeal isthmus/pharyngeal chiasma).

oropharynx

is part of the digestive tract, although air passes through it when the animal coughs or breathes orally. Its roof is formed by the soft palate, its floor is the root of the tongue and its lateral wall by the fauces (contains the palatine tonsil).

laryngopharynx

it is common to the respiratory and digestive channels; chief importance in deglutition. It is the caudal continuation of the oropharynx and extends from the base of epiglottis to about the level of cricoid cartilage of the larynx.

Limen pharyngoesophageum

(formerly the annular fold) an annular ridge of tissue marking the pharyngoesophageal junction in dogs.

tonsil

Aggregation of lymphatic tissue in the pharyngeal mucosa. Some are distinct accumulations and others are diffuse and difficult to see.

tonsil

They help to protect the openings of the pharynx against microorganisms and toxic substances.

esophagus, stomach, small intestine, large intestine, and anal canal

alimentary canal consists of?

liver and pancreas

two large glands associated with the alimentary canal

esophagus

The first part of the alimentary canal; is the musculo-membranous connecting tube between the laryngopharynx and the stomach; it is capable of great dilatation.

cervical, thoracic, abdominal (shortest)

portions of the esophagus

esophagus

It begins opposite the middle of the axis (dorsally) and the caudal border of the cricoid cartilage (ventrally); it ends in the cardia of the stomach.

limen laryngoesophageum

the internal demarcation between the pharynx and esophagus.

esophagus

It varies in diameter, where the diameter is narrow, the muscular wall is thick; where the diameter is wide, the muscular wall is thin.

cervical portion (pars cervicalis)

Related mainly to the left longus colli and longus capitis muscles dorsally; to the trachea ventrally and to the right.

cervical portion (pars cervicalis)

It runs through the ventral surface of cervical vertebrae and the trachea but as it approaches the thoracic inlet it shifts from its median position and passes to the left side of the trachea.

thoracic portion

It runs caudally in the dorsal mediastinum, passes dorsal to the tracheal bifurcation and crosses the right side of the aortic arch.

thoracic portion (pars thoracica)

It ends to the esophageal hiatus of the diaphragm.

abdominal portion (pars abdominalis)

The wedge-shaped terminal part located at the cardia of the stomach.

fibrous (adventitia), muscular, submucous, mucous

Coats of the esophagus

stomach (gaster/ventriculus)

The largest dilatation of the alimentary canal is a musculoglandular organ between the esophagus and the small intestine.