Lecture 34: Oral Cavity Flashcards
The prescence of teeth divides the mouth into two what two spaces
Vestibule and oral cavity proper
What is the space between the lips/cheeks and teeth
Vestibule
What is the space internal to the teeth
Oral cavity proper
Under normal conditions the oral vestibular and oral cavity are both just ____
Potential spaces
The oral cavity proper is almost completely filled by
The tongue
How does the mobility of the tongue change depending on what portion you are referring to
Rostral portion is very mobile
Partially mobile toward central portion that is fixed to floor of oral cavity
Caudal portion is relatively immobile
What attaches the central portion of the tongue to the floor of the oral cavity
Frenulum
What is the caudal portion of the tongue attached to
Basihyoid bone and epiglottis
What are the valleculae
Two small pockets on either side of the midline as a result of the attachment of the caudal tongue to epiglottis
The dorsal surface of the tongue is characterized by the presence of several different kinds of ___
Papillae
To protect from sharp particles of the food the dorsal surface of the tongue is mostly covered in ____
Small keratinized filiform papillae which are not associated with taste buds
What are the 3 types of papillae that are scattered throughout the tongue
Larger fungiform, foliate, vallate
Which papillae is the largest and typically restricted to a line or area towards the caudal end of the dorsal surface
Vallate papillae
In felines keratinized filiform are much ____ and tend to be directed ____
Larger and caudally
What is the lyssa
Stiff CT rod embedded in the apex of the tongue, function is unknown but most likely works as a dynamic stiffening rod to help support the extensive freely mobile apex
What two groups can the muscles of the tongue be divided into
Intrinsic and extrinsic
What muscle group of the tongue forms the dorsal and lateral parts of the body of the tongue
Intrinsic
What muscle group of the tongue originate on other structures and insert onto tongue
Extrinsic
What muscle group of tongue controls the position and gross movements
Extrinsic
What muscle group of the tongue control the shape and fine movements of the tongue
Intrinsic muscles
What nerve innervates both intrinsic and extrinsic muscles of the tongue (except palatoglossus)
Hypoglossal (CN XII)
Genioglossus OINA
O: medial surface of the mandible
I: midline ventral surface of the tongue
N: hypoglossal
A: depress the tongue
Hyoglossus OINA
O: basihyoid
I: lateral side of the caudal portion of the tongue
N: hypoglossal
A: retract the tongue
Styloglossus
O: stylohyoid
I: lateral surface of the tongue along most of the length
N: hypoglossal
A: retract the tongue
Geniohyoid OINA
O: intermandibular articulation
I: basihyoid
H: hypoglossal nerve
A: draws the hyoid apparatus and larynx rostrally
What is the major vessel that supplies the tongue
Lingual artery
What does the lingual artery branch off of
external carotid artery
What is the pathway of the lingual artery
Enters the oral cavity on the medial surface of the hypoglossus muscle, the runs on the lateral surface of the genioglossus muscle as it courses through the tongue to the apex, in the apex the name changes to deep lingual artery and found ear ventral surface
Ateriovenous anastomoses in the apex of the tongue facilitates efficient ____
Heat exchange and cool the animal during panting
What nerve supplies motor to all the intrinsic and extrinsic tongue muscles (except 1)
Hypoglossal
What is the pathway of the hypoglossal nerve
After crossing through the cranial neck the hypoglossal nerve runs with the lingual artery toward the oral cavity
It enters the oral cavity on the lateral surface of the hyoglossus muscle
What four cranial nerves contribute to sensory (general and taste) innervation to the tongue
CN V3-lingual branch, CN VII (facial), CN IX (glossopharyngeal), CN X (vagus)
What two cranial nerves supply the rostral portion of the tongue (rostral to vallate papillae)
CNV3 and CN VII
What CN supplies general sensory to the rostral portion of the tongue
Lingual nerve- branch off CN V3
What CN supplies taste from the rostral portion of the tongue
Fibers from the facial CN VII, via the chorda tympani, hitchhiking on lingual nerve
What cranial nerves supply the caudal portion of the tongue (including around the vallate papillae)
Glossopharyngeal (CN IX) and vagus (X)
What nerve provides both general sensory and taste to the most caudal tongue
Glossopharyngeal
What nerve provides both general sensory and a little bit of taste from the tongue around the epiglottis
Vagus
What are the four regional salivary glands
Parotid, mandibular, sublingual, buccal (called zygomatic in dogs)
What drains the parotid gland
Single long parotid duct that crosses the masseter superficially
Where does the long parotid duct drain to
Oral cavity on the buccal surface rostral to the edge of the masseter muscle (in dog opposite to fourth maxillary premolar)
What gland is sandwiched in between the maxillary and linguofacial veins
Mandibular
What is the pathway of the mandibular ducts
Run from medial surface of the gland through the floor of the oral cavity to empty in the rostral part of the oral cavity
How are the sublingual glands distinguished
Based on their drainage pattern- monostomatic vs polystomatic
How does the monostomatic sublingual gland drain
Drains via a single major sublingual duct that runs parallel to mandibular duct
What species does not have the monostomatic sublingual gland
Horses
What is the polystomatic gland and how does it drain
Collection of smaller more diffuse lobules of glandular tissue that drain directly via numerous small ducts through the floor of the oral cavity
Where do both the mandibular and major sublingual ducts drain into
Empty into the oral cavity at the sublingual caruncle
What is the sublingual caruncle
Small bump of tissue just lateral to the root of the lingual frenulum
Do salivary glands receive PNS or SNS innervation
Both
What ganglion do postganglionic sympathetics to the salivary glands come from
Cranial cervical ganglion
What is the pathway of postganglionic sympathetics from the cranial cervical ganglion
Axons form periarterial plexiand follow arteries to the target organs (lingual to mandibular and sublingual glands)
Some postganglionic sympathetics pass through parasympathetic ganglia (no synapse), and distribute to target organs with parasympatheticswh
Parasympathetics leave the brain in what four cranial nerves
Vagus, oculomotor, facial, and glossopharyngeal
What ganglion receive PNS innervation from facial nerve
Pterygopalatine ganglion and mandibular and sublingual ganglia
Parasympathetics to mandibular and sublingual salivary glands receive innervation from what ganglion
Mandibular and sublingual ganglia
What ganglion receives PNS innervation from the glossopharyngeal nerve
Otic ganglion
What salivary glands receive parasympathetic innervation coming from otic ganglion
Parotid and buccal/zygomatic
What is the presynaptic pathway for glossopharyngeal to otic ganglion
CN IX travels through middle ear, middle cranial fossa and foramen ovale to synapse on otic ganglion
What is postsynaptic pathway of CN IX after synapsing at otic ganglion
Hitchhike on auriculotemporal nerve and its branches to reach parotid and zygomatic glands
Describe the entire pre to postsynaptic pathway from glossopharyngeal CN IX to parotid gland
- CN IX passes through jugular foramen (pre)
- Becomes tympanic branch in middle ear (pre)
- Continues through middle cranial fossa and foramen ovale to become minor petrosal nerve (pre)
- Synapse at otic ganglion in infratemporal fossa
- Hitchhikes on auriculotemporal nerve (post)
- Innervates parotid gland on lateral face
What is the preganglionic pathway from CN VII to mandibular and sublingual ganglia
Preganglionic PNS from CN VII travel through the ear to infratemporal fossa and join lingual nerve to hitchhike to mandibular and sublingual ganglia for synapse
Describe the pathway of postganglionic PNS from mandibular or sublingual ganglia
Pass directly to glands
Describe the entire pathway of innervation (pre and post) from CN VII to mandibular gland
- CN VII passes through internal acoustic meatus
- Enters temporal bone and becomes chorda tympani (pre) which passes through middle ear
- Hops on lingual nerve in infratemporal fossa
- Synapse at mandibular ganglion in oral cavity
- Direct post synaptic fibers travel through to cranial neck and synapse at mandibular ganglion (post)