Lecture 18: Orbit, Eye, and Ear Flashcards
What seven walls make up the orbit of the eye?
1) Frontal
2) Lacrimal
3) Palatine
4) Maxillary
5) Zygomatic
6) Sphenoid
7) Ethmoid
Label the following
Which cranial nerve provides parasympathetic control to the lacrimal apparatus?
Facial nerve
_____ is the opening from the pterygopalatine fossa
Inferior orbital fissure
Label the following:
Once the lacrimal gland secretes tears, how are they transported from the gland to the conjunctival sac?
Lacrimal duct
How are tears transported from the conjunctival sac to the nasolacrimal duct?
Lacrimal canaliculi
The cornea, sclera, and limbus (cornea sclera junction) make up which layer of the eye?
Fibrous, external layer
____: tough coating of the eye, white part
___: transparent part of eye, covers lens and supporting structures
Sclera
Cornea
What is the pathway that tears take?
Which layer of the eye is associated with vasculature?
Middle layer of the eye
Which layer of the eye contains the following?
- choroid
- ciliary body (and processes)
- iris
- pupil
- sphincter/dilator papillae
Vascular layer (choroid)
______: located between fibrous later and retina, houses capillary lamina compex
Choroid
Capillary lamina supplies blood supply to which layer of the eye?
Choroid
Label the following:
Which structure of the eye secretes aqueous humor into the anterior chamber?
Ciliary processes
____: Thin diaphragm anterior to lens, manipulates amount of light entering the eye
____: Central aperture of iris, where light enters eyeball
Iris
Pupil
Ciliary Body connects the choroid to which structures?
Lens and Iris
Which muscles are indicated by the orange and blue regions? Function of those muscles?
Orange = Dilator Papillae (dilates pupil, sympathetic innervation)
Blue = Sphincter Papillae (constricts pupil, parasympathetic innervation)
The optic disc, macula lutea, and fovea centralis composed which part of the inner layer of the eye?
Fundus of the eyeball
____: spot where CN II enters, creating a blind spot
____: location for visual acuity lateral to optic disc
___: center of macula, spot for light to focus
Optic disc: spot where CN II enters, creating a blind spot
Macula lutea: location for visual acuity lateral to optic disc
Fovea centralis: center of macula, spot for light to focus
True or False: Aqueous humor helps refract light, helps light be focused on an object
True
Label the following
Which layer of the retina are rods and cones found in?
Neural Layer
A. Photoreceptive Neuron Layer
Which layer of the retina (Optic or Non-visual Layer) contains: light receptive cells, rods (low light) and cones (color) ; optic nerve; bipolar neurons; ganglia layers
Optic Layer
Macula lutea is also known as the ___
fovea
Label the chambers of the eye:
True or False: Both the anterior and posterior chamber of the eye contain aqueous humor
False (anterior only! - made by ciliary body)
Which chamber of the eyeball contains Aqueous Humor?
Anterior Chamber
(helps refract light + provides nutrients to surrounding structures)
Which chamber of the eye is located between the iris/pupil and lens/ciliary body?
Posterior Chamber
Which muscle change the shape of the lens and focal distance?
Ciliary muscles
___: Active process of lens manipulation, parasympathetic control via CN III
Accommodation
Why can trauma to the eye dislodge or detach the retina?
Pigmented and Neural layer are not firmly held onto each other
____: a disease of the eye associated with deterioration of the lens
____: a condition in which the lens becomes more opaque, making it more challenging for light to enter
Presbyopia (Age-related Farsightedness)
Cataracts
Cause of glaucoma?
Imbalance of aqueous humor production and removal
Which chamber of the eye contains Vitreous Humor?
Posterior Chamber
What are the three types of extra-ocular muscles
Levator Palpebrae Superioris
Rectus Muscles (4)
The Obliques (2)
Name this muscle:
What is its function and origin?
Levator Palpebral Superiosis
Action: Elevates upper eyelid
Origin: Sphenoid
What is the origin for the following eye muscles:
* Superior Rectus
* Medial Rectus
* Lateral Rectus
* Inferior Rectus
The rectus muscles originate in the common tendinous ring
Which eye muscles originates in the inferomedial orbital floor?
Inferior Oblique Muscle
Label the following muscles and the CN that innervates them
Label the following muscles and the CN that innervates them
True or False: The Superior and Inferior rectus muscle are important for eye ADduction, while the Lateral Rectus is important ABducting and the Medial Rectus is important ADducting
True
Which muscle functions to elevate, adduct, and medially rotate?
Which muscle functions to depress, adduct, and laterally rotate?
Superior rectus = elevate, adduct, and medially rotate
Inferior rectus = depress, adduct, and laterally rotate
Intorsion (medial rotation) and Extorsion (lateral rotation) are predominately done by which muscle?
Oblique muscles
Which eye muscle is innervated by the abducens nerve?
Which eye muscle is innervated by the trochlear nerve?
Abducens = lateral rectus
Trochlear = superior oblique
Functions of the Inferior Oblique?
Functions of the Superior Oblique?
Which cranial nerve is important for special sense of vision?
Which nerve provides motor function to some extraocular muscles, as well as levator palpebrae superioris?
Optic Nerve (neuronal layer of retina)
Oculomotor Nerve
Which cranial nerve carries a pre-synpaptic parasympathetic fiber to cilliary ganglion?
Oculomotor
Which cranial nerve provides motor function to superior oblique muscle?
Which cranial nerve provides motor function to the lateral rectus?
Trochlear = superior oblique muscle
Abducens = lateral rectus
Which cranial nerve will provide general sensation to the orbit and the eye, as well as superior orbital fissure?
Trigeminal (V1)
What three nerves branch off of the opthalmic n.?
1) Lacrimal: lac gland
2) Frontal: eyelid, forehead, scalp via: supratrochlear/supraorbital
3) Nasociliary: eyeball, orbit, face
3A) Infratrochlear: eyelids, conjunctiva
Which cranial nerve travels alongside lacrimal n on its way to lacrimal gland?
CN 7
Ciliary ganglion are: ____ ganglion that include passage of general sensory fibers from NASOCILIARY n., PRESYNAPTIC PS FIBERS FROM CN3 (synapse here); and POSTSYNAPTIC SYMPATHETIC FIBERS from _____
parasympathetic ; internal carotid plexus
Which ciliary nerves form post-synaptic para/sympathetic fibers to iris and cornea?
Short Ciliary Nerves
Which ciliary nerves are post-synaptic fibers that act on dilator papillae
Long Ciliary Nerves
The main artery for the eye? Where does it originate from?
Opthalmic a (internal carotid artery)
What three arteries branch off of the ophthalmic artery?
1) Central retinal artery = supplies retina
2) Muscular branches = EO muscles
3) Ciliary arteries = choroid and ciliary plexus
Label the arteries of the orbit
What structure drains the vascular layer of the eye?
Vorticose
Pupillary light reflex ensures that __ and ___ are responding properly
CN II (afferent)
CN III (efferent - parasympathetic)
Bones of the ear are located in which region of the head?
Temporal Bone
Label the external ear structures
____: passage from the auricle to tympanic membrane; modified sweat gland; secretes cerumen
External Acoustic Meatus
_____: separates external ear from middle ear
Tympanic Membrane (ear drum)
____: external cartilaginous structure that receives sound
Auricle
Label the external ear structures
Label borders of the inner ear
Which middle ear structure separates the external acoustic meatus from the tympanic cavity?
Lateral wall (Tympanic Membrane)
____: vertical wall that separate inner ear from tympanic cavity
Bony Labyrinth (Medial Wall)
_____: contains branch of CN IX. Carries sensory, parasympathetic, and sympathetic nerve fibers; provide innervation to middle ear and parotid gland via otic ganglion
Tympanic Plexus
_____: a structure of the middle ear that is covered by footplate of stapes and transmits vibrations from stapes to perilymph of vestibule
Oval Window
If ____, a structure of the middle ear was not present, perilymph would be incompressible
Round window
Label temporal arteries
The (anterior wall) carotid wall contains what two structures?
1) Pharyngotympanic Tube: Important fr draining and equalizing pressure
2) Tensor Tympani Muscle: attaches from bony tube to handle of malleus
Label the auditory bones
The head, neck, and handle of the malleus is embedded in the _____ and the ____ muscle inserts here, helps to stabilize and dampen membrane
tympanic membrane; tensor tympani muscle
The Incus is composed of ___, ___ /___
body; short/long crus
Which muscle tenses the tympanic membrane to dampen loud sound and is innervated by V3 (of CN 5)?
Tensor Tympani Muscle
Label the structures of the tympanic cavity:
What are the three auditory bones that span from tympanic membrane to oval window, transmitting vibrations from tympanic membrane by pushing oval window to produce wavs in the perilymph?
1) Malleus
2) Incus
3) Stapes
Which auditory muscle contracts, dampening sound by stabilizing incus footplate on oval window and is innervate by motor fiber by Facial nerve?
Stapedius Muscle
Label the structure of the Bony Labyrinth (medial wall)
Oval window is the superior opening while ___ is the inferior opening of the Medial Wall of the Tympanic Cavity
Round Window
Label the auditory bones
Label the malleus
Label the incus
Label the stapeus
Which cranial nerve inneravates the stapedius? Where does it go to?
Facial nerve
Stapes
Label tympanic membrane cavity musculature
What can cause ruptured tympanic membrane?
1) Foreign object
2) Changes in pressure
True or False: The Outer Ear is important for hearing and balance
False - inner ear
Label the structure of the Bony Labyrinth (Inner Ear)
_____: passageway from the vestibule of inner ear towards cochlear apex
scala vestibuli
____: apex, where the scala vestibule becomes scala tympani
Helicotrema
____: fluid between bony and membrane labyrinth
Perilymph
Main mechanism for perception of hearing and balance changes?
Movement of perilymph on endolymph fluids that bend hair cells
_____ lies between two perilymph chambers
Membraneous Labyrinth
____: continuous with saccule, spiral structure within cochlea
Cochlear Duct
What is found within the Membranous Labyrinth?
Endolymph
Which cranial nerve enters the internal acoustic meatus, turns posteriorly at geniculum (where geniculate sensory ganglion are present) and travels within the medial then posterior wall of tymp membrane?
Facial nerve
Which CN travels through the internal acoustic meatus to inner ear structures?
Vestibulocochlear nerve
_____: Passage from the posterior cranial fossa through which the facial nerve and vestibulochoclear nerve travel via a canal within the petrosal part of temporal bone to inner ear
Internal Acoustic Meatus
Hearing is the multi-step process of converting ____ into ___ energy then into ____.
From here, the waves are translated via sensorineural impulse by stimulating ___ cells
sound waves (air vibrations); mechanical energy (auditory bones vibrating); sonar waves (fluid vibrations)
hair cells
Stimulation of hair cells converts ____ into ___ signals and ___ impulses
mechanical; chemical signals; neuronal impulses
In the first step of hearing, the ___ receives the sound wave, which travels through the _____ and air vibrates against tympanic membrane
auricle; external acoustic meatus
In the second step of hearing, ____ membrane vibrates (converting sound waves into mechanical) by the vibration of: ___, ____, and ____ onto the oval window
tympanic membrane; malleus, incus, stapes
In the third step of hearing, there are vibrations on the ____ - translates into sonar waves (fluid vibrations) by pushing perilymph through vestibule
oval window
Sonar waves travel through the ___, toward inner apex, wrap around apex, the ___, toward round window, and travel out from the apex
cochlea; helicotrema
In the last stage of hearing, the ____ waves of the perilymph chambers propagate and vibrate _____, which in turn vibrates hair cells sitting in membrane.
As hair cells bend, they release chemical signals that create ____, which is picked up by CN VIII
sonar; basilar membrane; neuronal impulses
Hair cells closer to entrance of cochlea pick up ___ frequency while those deeper in the cochlea pick up ____ frequency
higher; lower
What is the difference between conductive and sensorineural hearing loss?
Conductive hearing loss involves: problem converting sound waves TO sonar waves from external ear to perilymph vibrations; from oval to round window
Sensorineural hearing los: nerve damage, relating to VC nerve and branches within inner ear; usually permanent; can improve with cochlear implants; cam also be caused by loss of hair cells
____: structure in the vestibular system that detect movement along vertical plane (up and down)
Saccule
_____: structure in the vestibular system that detect movement within horizontal plane
Utricle
_______: structure in vestibular system that detects rotational movements along x,y, and z axes
Semicircular canals
Lower frequencies near ____; higher frequencies near ____base
Helicotrema
Sound waves propagating through the ____
Vibrate the ____, in turn, vibrate hair cells
Hair cell tips connected to _____
As hair bends, release chemical signal to nerve to initiate impulse to brain
scala tympani
basilar membrane
tectorial membrane
What are the four modifiers that aid in converting sound to mech energy
When mechanical energy is converted to sonar energy:
____ vibrates oval window and propagates perilymph sonar waves
Sonar waves travel to ___
Round window balances ___
stapes
cochlea
oval window
The scala vestibuli contain perilymph from ____ while the scala tympani takes perilymph to ____
Cochlear Duct contains ___
vestibule; round window
endolymph
