audition Flashcards
(23 cards)
What is the place code?
The place code is the different frequencies that can be detected by the different areas on the cochlea due to their elasticity.
What causes sensory neural hearing loss?
Damage to the cochlea hairs
What causes Tinitus ?
When the hairs on the cochlea are damaged or destroyed.
The neurones in the cortex are idle so will ‘invent’ inputs , causing ringing in the ears.
Where does the auditory signal enter the brain ?
The medulla
what are the four physical properties of sound ?
Amplitude / intensity -the amount of energy in a sound
Frequency - how many air/ water compressions there are in a second
Sound source location
Duration - length of the sound
What are the three canals of the cochlea ?
tympanic, Vistibular and cochlea
How does the organ of Corti work ?
There are 4 rows of hairs in the membrane , the vibrations caused by the sound cause the hairs to bend , this opens the potassium and calcium channels and depolarises the cell - setting off signals in the neurones
How do MRI scans work ?
Magnetic pulse is put into the brain to disrupt the normal functioning of the neurones to see how they respond
Why do people get phantom pain ?
Phantom pain is when someone who has lost a limb , is still able to feel pain in the limb even when it isn’t there. The neurones in the brain from the limb will be invaded by other body areas.
What are the three bones of the middle ear ?
Hammer, Anvil and stirrup
what is golgi stain ?
A stain used to highlight the neurons because the stain is absorbed by them
what are myelin stains ?
myelin stains are dyes that are absorbed by the fatty myelin surrounding neurones
How do CT scans work ?
A dye is injected into the blood and x rays are fired at different angles, the dye will be absorbed at different intensities depending on the density of the tissues
What are the 4 lobes in each of the hemispheres of the brain ?
parietial , temporal, Frontal and Occupital
what is a sulcus ?
an indentation in the brain
What is the role of the partial lobe ?
Spacial localisation and body sensations
how is a lesion on the brain simulated in the lab ?
the part of the brain has an copper wire attached to it from the outside of the head with an impulse sent through it to disrupt the neuronal activity
what is Electroencephalography ?
a measure of the electrical brain activity. this technique is done by placing a hat on the patients head with electrodes on it
what is an MEG ? why might it be chosen over an event related potential ?
magentoencephalography records the magnetic fields produced by the electric currents on the brain , not obstructed by tissues
how does sound get from the ear to the brain ?
sound is funnelled in by the pinna , the vibrations go to the tympanic membrane where it sends the vibrations to the ossicles of the er
the ossicles vibrate sending the signal to the cohlea
the organ of corgi has 4 rows of hair cells on it , they vibrate and open the calcium and potassium channels which depolarise the cell and send the signal to the brain where it enters and goes to the medulla
what is sensorineural hearing loss caused by /
damage to the cochlea hair cells
How is frequency encoded by the brain ?
Frequencies above 200 Hz are encoded by neurone fringe rate, the rate of firing increases as the frequency grows
How are sounds lower than 200 Hz encoded ?
There are no specialised cells for these sounds, the whole of the cochlea will vibrate, the number of cells that vibrate will show the intensity of the sound
