auditory function and balance

Question 1

how is amplification achieved

Answer 1

lever system of articulated ossicles and ratio of area of tympanic membrane to oval window protective mechanisms

Question 2

what does the ear project the stimuli onto, how is this accomplished, and where are these

Answer 2

projects stimuli onto hair cells, via a series of mechanical coupling, which are the sensory receptor of the inner ear within the cochlea

Question 3

structure of hair cells

Answer 3

have a hair bundle on projecting surface, which is a cluster of modified microvilli (stereocilia)

Question 4

where do superior olivary complex neurones send feedback to

Answer 4

hair cells (mainly outer hair cells)

Question 5

effect of activity in superior olivary complex neurone fibres

Answer 5

increases representation of signals in noise and protects it from damage by loud sounds

Question 6

diagram of superior olivary complex neuronal feedback

Answer 6

Question 7

2 functions of activity of superior olivary complex neurones

Answer 7

balance responses from the two ears; reduce cochlea sensitivity

Question 8

what reduces amplitude of vibrations passing through ossicles

Answer 8

reflex contraction of tensor tympani and stapedius muscles

Question 9

what does auditory tube allow

Answer 9

equilibration of air pressure on either side of tympanic membrane

Question 10

2 types of hair cell

Answer 10

inner and outer hair cell

Question 11

how are inner hair cells arranged and innervated

Answer 11

3500 in single row, densley innervated by 10 sensory axons per cell (provide info for brain)

Question 12

how are outer hair cells arranged and innervated

Answer 12

20000 cells arranges in 3 rows, sparsely innervated, with 1 axon innervating several cells

Question 13

function of outer hair cells

Answer 13

efferent nerve causes cells to change shape -> amplifies response to sound of adjacent inner hair cells at centre of vibration

Question 14

diagram of auditory pathway from cochlea to brain

Answer 14