19 Auditory System Flashcards
What type of energy do auditory receptors pick on? and what energy is it converted into?
Within the ear, auditory receptors covert the mechanical energy of sounds into an electrical signal that is transmitted to the brain.
Parts that make up the outer ear.
Pinna - prominent fold of the cartilage-supported skin, captures the sound and focuses it into auditory canal.
Pathway into the brain of the outer ear?
Pinna –> Auditory Canal (Ends at air drum)
processes of the middle ear?
High and low-pressure regions impinge upon the eardrum.
High-pressure pushes the eardrum inward, low pressure made ear drum go outward.
Continual pressure makes the ear drum vibrate As the eardrum is attached to the bones, the bones begin to vibrate and turn the sound signal into mechanical vibrations
Vibrations are transmitted into fluid in the inner ear via vibration membrane of the oval window
Parts of the middle ear
Ear drum (tympanic membrain)
ossicles - middle air bone
step by step process of the inner ear?
Cochela vibrations produce waves in the fluid that cause hair cells to move
hair cells respond by turning mechanical signal into an electrical signal
within the cochela hair cells synapse on spiral ganglion cells.
parts of the inner ear
Cochela
Hair cells
Soiral ganglion cells
What is the tuning curve of a spiral ganglion cell?
they can be tuned to specific frequency (maximally sensitive to sound of 16000hz with firing rate dropping rapidly for lower and higher.
what is tinnitius?
hering noise in the absence of any sound stimulus
includes buzzing, humming, whistling
caused by a disease effected the cicheka or auditory nerve.
the pathway from the inner ear to the CNS. and the role.
Contains structures for both hearing and balance.
The axons of the spiral ganglion cells exit the cochela and converge with the axons of vestibular neruons to form vestibulocochlear nerve.
This nerve carries impulses for balance and hearing from ear to brain.
Thus information travels via the vestibulochlear nerve to the brain stem.
What is the vestibulocochlear Nerve and what does it do?
The vestibulocochlear nerve carries the signal from the cochlea into the brain stem, where the spiral ganglion cells synapse on neruons in the COHLEAR NUCLEI, which are located at the level of the lower pons-uppder medulla.
how does information ascend from the cochlear nuclei to the inferior colliculi?
Bilaterally, goes up two wires.
What do neurons in the inferior colliculus synapse on to?
Medical geniculate nucleus of the thalamus.
What do neurons in the gerniculate nucluse synapose onto?
Neurons in the primary auditory cortex.
Where is the first region of the cortex to process sound located?
Superior temporal lobe and buried within the lateral sulcus (A1)
