The ear, hearing and equilibrium Flashcards
What is the external outer ear responsible for?
Collects sound waves
What does the middle ear contain?
- 3 auditory ossicles
- the oval window
- the round window
What does the inner internal ear contain?
- Receptors for hearing
- Receptors for dynamic and static equilibrium
What are the external ear structures?
- Auricle or pinna
- Externals auditory canal
- Tympanic membrane
What is Auricle or pinna?
- Elastic cartilage covered with skin
- Directs sound waves towards the tympanic membrane (eardrum)
Describe the Externals auditory canal?
- Curved tube of cartilage and bone leading into temporal bone
- Ceruminous glands produce cerumen (earwax)
- Cerumen lubricates and protects the external canal
Describe the Tympanic membrane?
- Thin semi-transparent membrane that separates the external and middle ear
- Sound waves vibrate the tympanic membrane and transfer that energy to the ossicles
What is the middle ear structure?
- Malleus
- Incus
- Stapes
- Auditory tube
What is the inner ear divided into?
- The vestibule
- The cochlea
- The semicircular canals
What are the two main division of the inner ear?
- Bony labyrinth
- Membranous labyrinth
What are the three channels of the cochlea?
- Scala vestiboli
- Cochlea duct
- Scala tympani
Name the three ossicles?
- Malleus
- Incus
- Stapes
Where are high pitched sounds detected?
At the base of the cochlea
Where are low pitched sounds detected?
At the apex of the cochlea
The vestibule is responsible for what?
Static equilibrium
The semi-circular canals are responsible for what?
Dynamic equilibrium
What is the order of the auditory pathway?
1 - sound waves vibrate the tympanic membrane
2 - vibration of the ossicles transfers and amplifies the vibratory motion to the oval window
3 - pressure waves are created in the perilymph of the cochlea labyrinth
4 - pressure waves travel through the perilymph, pass through the vestibular membrane and into endolymph
5 - pressure waves in the endolymph cause the basilar membrane to vibrate. This moves the hair cells and creates an action potential (nerve impulse)
Endolymph is found within the what?
Cochlear duct
Nerve fibers that synapse with hair cells in the organ of Corti unite to form part of the _____ nerve
Vestibulocochlear
Sound waves are translated into nerve impulses in the?
Cochlea
The neural receptors for the sense of hearing are located in the?
Inner ear
What does the oval window connect to?
Stapes
What helps maintain proper air pressure in the middle ear?
Eustachian tube
Name the correct pathway leading to the perception of sound?
Tympanic membrane, ossicles, perilymph, endolymph, hair cells
Each crista in the semicircular ducts is covered by a gelatinous material called the?
Cupula
High intensity (loud) sounds can cause deafness because they are most damaging to the?
Hair cells of the spiral organ of Corti
Perilymph fills the?
Bony labyrinth
What are the three major areas of the ear?
External ear, middle ear, inner ear
What is the main focus of the pinna?
catch sound waves and pass them along further into the ear
What is the role of the tympanic membrane?
Main job is to amplify sound waves so they are stronger when they enter the inner ear
What is the role of the labyrinth?
- Turn those physical vibrations into electrical impulses that brain can identify as sounds.
- Helps maintain your equilibrium
What is the basilar membrane?
- A stiff band of tissue that runs between the scala media and scala tympanic in the cochlea.
- Reads every single sound within the range of human hearing and communicates it immediately to the NS
- It is covered in 1000s of fibres from short to long. The short fibres vibrate to high frequency pressure and the long fibres resonate to lower frequency pressure
