Ear! Flashcards
To learn the anatomy of the ear
What are the three parts of the ear?
External Ear, Middle Ear (within the Temporal bone), and Inner Ear (within the Temporal Bone)
What are the two components of the external ear as discussed in class?
Auricle and the External Acoustic Meatus
What is the auricle made up of?
Elastic Cartilage, covered with skin
Name the components of the auricle and describe each (6).
Helix - outer rim of the ear Antihelix - Inner rim (Y shaped) Tragus -prominence on inner side of external ear Antitragus - prominence above the lobule Cavus - entrance to the "cave" Lobule - Ear lobe!
How is the lobule different than the other components of the auricle?
It does NOT contain any cartilage.
It is the only part of the ear that continues to grow!
How long is the External Acoustic Meatus and what shape is it?
2-3cm, S-shape (therefore, to examine this structure, you must pull on the auricle to straighten out the canal)
What is the External Acoustic Meatus made up of?
Outer 1/3 - Elastic Cartilage
Inner 2/3 - Bony
What glands are in the external acoustic meatus, where are they located, and what does it secrete?
Ceruminous gland - secretes cerumen (ear wax) to prevent desiccation.
These glands are found in the outer 1/3 of the external acoustic meatus.
What is the external acoustic meatus sealed by?
The tympanic membrane (1cm diameter)
What are the parts of the tympanic membrane discussed in class?
Pars Tensa - fibrous (rigid)
Pars Flaccida - Air vibrations make it vibrate
Umbo - divet for tip of handle of malleus
What are the three components of the middle ear?
Tympanic Cavity, Auditory Ossicles, and the Pharyngotympanic tube (Eustachian tube)
What are the two components of the tympanic cavity?
Tympanic Cavity Proper - tube/cavity
Epitympanic Recess - aka the attic of the cavity - ossicles
The auditory ossicles stretch from what to what?
Tympanic Membrane to the Oval Window (membrane against fluid)
What kind of relationship does vibratory force and amplitude have?
Inverse.
When the vibratory force increases, the vibratory amplitude decreases.
What are the three auditory ossicles?
Malleus (hammer)
Incus (anvil)
Stapes (stirrup)
Name and describe the anatomy of the malleus (2).
Handle tip - draws in the tympanic membrane, creating the umbo (invagination)
Head - articulates with the incus
Name and describe the anatomy of the incus (3).
Body - articulate with the malleus
Short limb - attaches to the chamber wall
Long limb - articulates with stapes
Name and describe the anatomy of the stapes (3).
Head - Articulates with incus
Neck - Stapedius muscle location
Base (foot plate) - Presses against oval window
Name the muscles associated with the ossicles (as discussed in class).
Tensor Tympani
Stapedius Muscle
Details on the tensor tympani muscle, please!
Grabs the handle of the malleus
Dampens malleus-tympanic membrane
Details on the stapedius muscle, please!
Inserts into the neck of the stapes.
Reduces vibrations by pulling/tension
Pulls to stabilize position also
What happens with loss of function of a muscle associated with the ossicles?
Sensitivity - loud hearing
What is the purpose of the Eustachian tube?
Equalizes air pressure
Drains mucus from the tympanic chamber
What is the location of the Pharyngotympanic tube?
Stretches from the tympanic cavity to the nasopharynx
What is the E-tube made up of?
Proximal side(1/3) - bony Distal side (2/3) - cartilagenous, bound by muscles
Is the Eustachian tube usually open or closed?
Closed
When does the Eustachian tube open?
When swallowing
What is a Pastulous E-tube?
The Pharyngotympanic tube is always open.. an individual with this generally talks quiter because they hear themselves talking loudly since the tube is open
What is the anatomy of the inner ear?
Contains the Vestibulocochlear organ, the otic capsule, the bony labyrinth, and the membranous labyrinth.
What is the fluid called in the bony labyrinth of the inner ear?
Perilymph (which is cerebrospinal fluid)
Where is the membranous labyrinth located?
Within the bony labryinth of the inner ear.
What is the fluid of the membranous labyrith called and what is it high in?
The fluid is called endolymph and it is high in potassium.
What is the anatomy of the membranous labyrinth (3) and the function of each part?
Cochlear - auditory
Vestibule - static equilibrium (propioception) and the detection of acceleration
Semicircular Canals - Dynamic equilibrium (detects movement)
