The Ear and Hearing Flashcards
What are the three parts of the ear?
Outer ear
Middle ear
Inner ear
What are the three parts of the Outer ear?
Aurical / Pinna
External auditory meatus (ear canal)
Tympanum (ear drum)
What is the role of Outer ear?
Converts acoustic energy into kinetic energy
Why is the auricle and external auditory meatus shaped in a specific way?
To preferentially filter and amplify sounds for human speech
What is the shape of External auditory meatus?
Sigmoidal shaped
Describe what the External auditory meatus is surrounded by?
First 1/3rd of canal is surrounded by cartilage
Last 2/3rds of canal is surrounded by bone
What is found in the Cartilaginous portion of the Eardrum?
Hair, sebaceous glands, cerumineous glands
What structure separates the External ear from the Middle ear?
Tympanic membrane
The Tympanic membrane is concave externally - what is the most depressed part of the cavity called?
Umbo
Which bone is attached to the medial Tympanic surface?
Malleus
The three bones of the Middle ear are called?
Ossicles
What is the name of the three Ossicles in the ear? Lateral to medial
Malleus (hammer)
Incus (anvil)
Stapes (stirrup)
What is the function of the Eustachian tube?
Pressure equalisation between the middle ear and external ear
Where is the Eustachian tube located in the ear?
Middle ear
What are the middle ear muscles? What do they attach to?
Tensor tympani: Attached to the Malleus
Stapedius: Attached to the Stapes
What is the role of the Middle ear muscles?
Acoustic reflex against high intensity sounds
What is the innervation of the Middle ear muscles?
Stapedius: Facial nerve
Tensor Tympani: Mandibular branch of Trigeminal
Bone conducts what frequencies of sound compare to air conduction?
Bone conducts lower frequencies than via air conduction
The inner ear comprises what two structures?
Cochlear (hearing) Vestibular system (balance)
What are the three structures of the Cohlear?
- Scala media
- Scala vestibuli
- Scala tympanic
What is the range of human hearing?
20 Hz to 20,000 Hz
What is “Ultrasound” and “Infrasound”
Ultrasound: Beyond human hearing range
Infrasound: Below human hearing range
What are the two types of Cillia on the Cochlear hair cells?
Sterocilla (short) and Kinocillium (long)
Describe the path of the Auditory pathway (SLIM)
Superior Olivary Complex -> Lateral Lemniscus -> Inferior Colliculus -> Medial Geniculate Nucleus
Where is the auditory cortex located in the brain?
Temporal lobe
What are the two types of hearing loss?
Conductive hearing loss
Sensorineural hearing loss
What is Conductive hearing loss?
Problems conducting sound waves through outer ear, eardrum or middle ear
What is Sensorineural hearing loss?
Problems in the cochlea, vestibulocochlear nerve or auditory cortex of brain
By performing the Rinne’s test, and it is found that Air Conduction (AC) is better than Bone Conduction (BC) - what does this mean?
Either normal, or sensorineural deafness
By performing the Rinne’s test, and it is found that Bone Conduction (BC) is better than Air Conduction (BC) - what does this mean?
Conductive deafness
I have performed a Rinne test which found AC > BC, after performing Weber’s the patient said they sounded the noise louder on the right side - what is the diagnosis?
Left sensorineural deafness
I have performed a Rinne test which found AC > BC, after performing Weber’s the patient said they sounded the noise louder on the left side - what is the diagnosis?
Right sensorineural deafness
