Ear And Oral Cavity Flashcards
External ear boundaries and functions
From pinna/auricle to tympanic membrane
Function: collecting sound waves
Ear auricle make
Elastic cartilage as the scaffold
Ear auricle somatic sensation
Variable mappings
CN 5, 7, 9, 10
Lesser occipital nerve: C2 ventral ramus
Greater auricular nerve: C2 and C3
Middle ear boundaries
Between tympanic membrane and bony cages for vestibulocochlear organs
Middle ear function
Transforming sound waves into controllable mechanical vibrations
Tympanic cavity: contents
Auditory ossicles
Pharyngotympanic tube (eustachian tube)
Malleus
“Handle” interacts w/ tympanic membrane
*chorda tympani nerve runs medial to handle
Auditory ossicles (3)
Mallius, incus, and stapes
Lateral → medial
Tympanic cavity boundaries
Lateral Wall: tympanic membrane
Medial wall: labyrinthine
Roof: segmental part of the temporal bone (middle cranial fossa)
Floor: Internal jugular vein
Anterior wall: Internal carotid artery
Posterior wall: mastoid sinus
Tympanic cavity: medial wall
Labyrinthine
Innervation: CN 7 - facial nerve
Contents: promontory w/ tympanic plexus, oval and round window, and horizontal semicircular canal
Branches of CN 9
Tympanic nerve
Stylopharyngeal nerve
Lingual branches
Communicating branches to the vagus nerve anastomosis
Carotid branch
Carotid branch of CN 9
Bifurcation of the common carotid artery, visceral sensory not following visceral motor
Tensor tympani
Stapedius
P: pyramidal eminence
Di neck of stapes
I: nerve to stapedius (cn 7)
A: dampening vibrations passed to the cochlea via the oval window
Hyperacusis
A disorder in loudness perception
Inner ear boundaries
From vestibulocochlear organs to the internal acoustic meatus
Vestibular system
Otolith organs
Semicircular canals
Sensory receptors
Otolith organs
Semiscircular canals
Sensory receptors
Hair cells
Benign paroxysmal positional vertigo (bppv)
Dislodge of the otocnia into the semicircular canals
** mainly from the utricle
** most common and misdiagnosed “dizziness”
Signs/symptoms: nystagmus, interaction of CN 6 and 8
Cochlear system
Hearing
1. Scala vestibuli
2. Scala media: organ of corti, hair cells as the sensory receptor
3. Scala tympani
Cochlear system: Scala vestibuli
Cochlear system:
Cochlear system:
Inner ear innervation: cochlear component
Cochlear division of CN 8
Inner ear innervation: cochlear component
Cochlear division of CN 8
Innervation of inner ear
Localization
Distance and location from sound origin
Blood supply to inner ear
Labyrinth
Oral cavity boundaries
Anterior: oral orifice, orbicularis oris
Lateral buccinator
Posterior: pterygomendibular raphe
Roof: hard and soft palate
Floor: myohyoid and
Hard palate bones
Maxilla and Paladin
Teeth
Specialize skin appendage
Parts: crown, root, neck, pulp cavity
32 in adult teeth (-4 for removal of wisdom teeth)
Oral cavity innovation
Maxillary nerve: buccal nerve, superior alveolar nerve (post, middle, ant)
Mandibular nerve
Soft palate muscles
Tensor veli palatini
Levator veil palatini
Uvula
Tensor veli palatini
Lateral
Levator veli palatini
Uvula
Tongue parts and functions
Oral part
Pharyngeal part
Function: stir and mix food, taste, and speech
Tongue: oral part
Tongue: pharyngeal part
Tongue: pharyngeal part
Extrinsic tongue muscle: palatoglossus
Extrinsic tongue: styloglossus
P: styled process
Di lateral tongue and blending
Extrinsic tone muscle: hyoglossus
Extrinsic tongue muscle: genioglossus
P: superior mental spire
D: inferior tongue
Intrinsic tongue muscles functions
Stir and mix the food and speech
CN 12 deficiency
Imbalance of bilateral intrinsic and extrinsic muscles
* protrusion of the tongue will deviate to the weaker side: opposite to the muscular deficiency
Soft palate arches
Anteriorly: palatoglosseal
Posteriorly: palatopharyngeakl
Tongue: sensation
Salivatory glands function
Moisture to the mucosal surface of the oral cavity
Mix food during mastication
Digest starch
Saliatory glands: visceral innervation
