21. Oral Cavity Flashcards
What is the boundary and contents of the oral cavity proper?
What is the boundary and contents of the vestibule?
OCP: area within dental arches = ant 2/3 tongue, lingual frenulum (submandibular gland opening), plica sublingualis (sublingual gland opening)
V: between lips and teeth = loose/attached gingiva (gums), labial frenulum (tether, upper and lower), openings of parotid gland ducts (adjacent to second molars)
What is the roof of the oral cavity and its features?
Bony Palate
Maxilla: incisive canal (for nasopalatine n.)
Horizontal plate of Palatine: Greater/lesser palatine foramina/canals, posterior nasal spine
2 incisors, 1 canine, 2 premolars, 3 molars on each side
Soft Palate
Uvula
Numerous salivary glands - innervated by parasymps on nasopalatine and greater/lesser palatine nerves (pterygopalatine ganglion)
What muscles mark the floor of the oral cavity?
what marks the lateral wall of the oral cavity?
Mylohyoid m. - true floor
Geniohyoid m. - above mylohyoid m.
Genioglossus m. - extends into whole tongue
Buccinator - lateral wall
Posterior Oral Cavity
What features divide oral cavity and oropharynx?
What features of the tongue have taste buds? Which do not?
What muscles raise and lower the soft palate? What is the name of the cartilage of the auditory tube?
Sulcus Terminalis, Foramen Cecum, Palatoglossal Arch (also pulls down soft palate)
Circumvalate Papillae (big) Foliate Papillae (ridges) Fungiform Papilla Filiform Papilla (invisible but give tongue texture; no taste buds)
Levator palati - raises soft palate
Palatopharyngeus m. - lowers soft palate (along with palatoglossus)
Tensor veli pallatini m. - tenses soft palate
Torus tubarius - cartilage of auditory tube
Where does the oral cavity develop from?
What nerves are general sensory in the oral cavity?
What nerve does the gag reflex?
Stomodeum - invagination of surface ectoderm, inside lining of 1st pharyngeal arch
V3 - lingual n. buccal n.
V2 - nasopalatine, greater palatine, lesser palatine n.
CN IX does gag reflex (Pharyngeal Arch 2 diminishes)
How does the face develop? How does this lead to the formation of cleft lip?
Flanking stomodeum: Frontonasal process and maxillary/mandibular parts of 1st pharyngeal arch
- Medial and Lateral Nasal Swellings appear on frontonasal process
- Medial Nasal Swellings fuse to intermaxillary segment = primary palate (and external nose and part of upper lip)
Cleft lips form at the fusion of the primary palate to the maxillary part of the 1st arch, which is just off line of the upper lip
How do the nasal cavity and palate develop? How does this explain the site of cleft lip? What are the different types of cleft lip and why is it a problem at birth?
- Olfactory placode invaginates = nasal sac = breaks through to stomodeum behind primary palate
- Secondary palate forms from fusion of lateral palatine processes = posterior maxilla, palatines, soft palate (also need to fuse to nasal septum
Cleft Palate: incomplete fusion of lateral palatine plates, occurs MIDLINE (also may not fuse to nasal septum)
unilateral: 1 lateral palatine process does not fuse to the other nor the nasal septum
complete: both lateral palatine processes do not fuse to each other, nor the nasal septum
Problem: hole to nasal cavity, baby can not create suction to feed
Tongue muscles and their innervation
All innervated by CN 12 (except palatoglossus - CN X)
Intrinsic Tongue m.
Genioglossus (protracts - keeps from swallowing, retracts, and depresses tongue)
Hyoglossus (depress/retract)
Styloglossus (retract/elevate)
Sensory innervation of tongue
Which nerve within the tongue is superficial? Which is deep/hard to see? Which spirals? Under what?
Ant 2/3: Gen sensory (V3 - lingual nerve), Taste (CN 7, chorda tympani)
Post 1/3: front part (CN IX visceral sensory/taste/gag reflex), back part (CN X visceral sensory/taste)
Lingual nerve is superficial, hypoglossal nerve is deep
Lingual nerve spirals under submandibular duct
