Ear Anatomy & Hearing Flashcards
What is the function of the elastic cartilage of the pinna?
Gather sound
What is the external auditory meatus?
Ear canal
What is cerumen? Which gland produces it?
Ear wax - protects from damage and infection
Ceruminous glands - modified sebaceous gland
What does the cochlea contain?
Round window
Oval window
What are the auditory ossicles? What do they do/
Stirrup Hammer Anvil
Connect together via synovial joints, form flexible chain from tympanic membrane to oval window
What is the function of the tympanic membrane?
Convey vibrations from ear canal to ossicles
What is the tympanic bulla?
An air filled space containing the ossicles
Attached to middle ear cavity
What does the auditory tube do?
Connect middle ear to nasopharynx
Equalises pressure either side of ear drum
How do animals hear?
Ear drum vibrates Ossicles vibrate Stirrup pushes in and out of oval window Perilymph moves Pressure waves transmit from vestibule to tympani, to endolymph
What are the functions of the inner ear?
Balance - proprioception of head
Hearing - convert middle ear vibration to electrochemical signals
What is the bony labyrinth?
Convoluted tubule on the side and base of the skull Contains vestibule (balance), semi-circular canal (balance) and cochlea (hearing)
What does the round window contain?
Organ of Corti (contains hair cells which convert vibration to electrochemical signal)
Act as microphone
In which part of the cochlea are lower frequencies heard?
Outside - hears
Inside - higher frequency, no hairs
Which nerve innervates the inner ear? Where do axons travel to in the brain?
CN VIII - vestibulocochlear
To midbrain, thalamus and auditory cortex
What is otitis externa? What causes it?
Inflammation of the ear canal
Mites, fungi, bacteria
