concept 50.2: in hearing and equilibrium, mechanoreceptors detect moving fluid or settling particles

mechanoreceptors

they detect settling particles or moving fluid

how does hearing work

vibrating objects create percussion waves in the air that cause the tympanic membrane (eardrum) to vibrate, and the vibration of this causes small bones in the middle ear to vibrate and the vibrations are moved on to the cochlea where hair cells are in the cochlea create pressure waves

tympanic membrane

the eardrum- the first place sound waves enter

ossicles

small bones in the middle ear that vibrate as a result of the vibrations in the tympanic membrane

the middle ear

has three bones that that transmit the vibrations to the oval window

oval window

the entrance to the cochlea

the cochlea

has hair cells- mechanoreceptors- that are simulated and they cause changes in the membrane potential in the sensory cells and this action potentials

the ear conveys information about what

volume- the amplitude of the sound wave

pitch- the frequency of the sound wave

how is volume determined in the ear

determined by how much distortion the hair cells are receiving- more distortion = higher volume

what is pitch determined by

determined by which area of the basilar membrane moves and which hair cells are stimulated- low frequency= hair cells far away, high frequency= hair cells close to the oval window

what does the ear provide other than hearing

body movement, position and balance

what do the utricle, saccule, and otoliths work together and do

the utricle and saccule contain granules called otoliths that sit on hair cells and the movement of the otoliths bend the cilia on hair cells and allow us to perceive our heads position relative to gravity or linear movement (horizonal or vertical movement)

what do the semicircular canals detect for us

angular movement in any direction

what happens when the body moves

the the otoliths in the utricle and saccule or fluid in the semicircular canal to lag behind and the hair cells send a signal to the brain