H&N week 11- Ear and Eye Flashcards
Label this diagram of the ear
Label this diagram of the middle ear.
Label this diagram of the inner ear.
Discuss the 3 parts of the ear
External ear gathers soundwaves
It is made of the aurcicle and the external aucoustic meatus.
Middle ear- magnifies the sound vibrations
This contains air and 3 ossciles (malleus, incus and stapes)
Inner ear- For hearing and balance.
This contains the semi-circular canals and cochlea
Where is the chordae tympani found?
Inside the tympanic membrane.
Discuss the safety mechanisms of the external ear.
Hairs- to prevent bodies entering
Ceruminous glands- to produce wax.
What is otitis externa?
Inflammation of the skin lining.
Discuss the auricle
Function: gathers sound and sends it into the aucoustic meatus
Made of: A skeleton of elastic cartilage and lined with skin.
It is also known as the Pinna.
What is the external aucoustic meatus?
A bony canal running from the outer ear to the middle ear.
The outer part of the canal is made of cartilage and the inner part is made of bone.
What is the tympanic membrane
A thin membrane in the middle ear that is made of skin and collagen.
It sits under tension and vibrates when soundwaves come through.
What is the umbo?
The most concave part of the tympanic membrane.
How is the ear protected from loud sounds?
Tensor tympani muscle
- A tendon attached to the handle of the malleus
- it contracts to hold the malleus more steady, reducing vibrations
- Supplied by CN5
Stapedius muscle.
- It contracts and anchors the stapes to reduce movement
- Supplied by CN7
What is the tympanic cavity ?
Where you find the ossicles.
What is the Malleus?
A hammer shaped bone which attaches to the central part of the tympanic membrane.
What is the incus?
An anvil shaped bone which has a long process that articulates with the stapes
What is the stapes?
A bone that is shaped like a horse stirup (food rest) whcih fits into an inner window that seperates the middle and inner ear.
How does the stapes magnify sounds?
the tympanic membrane vibrates causing the food plate of the Stapes to move in and out.
This causes the movement of fluid.
How are sounds converted to electrical impulses?
the movement of fluid to the inner ear causes the movement of special receptor cells (hair cells with long cilia) and convert to electrical impulses.