Question

This is a list of some of the steps in the process of hearing a sound. Put them in cause-and-effect order from first to last.

A. K+ channels in the hair cell membranes open

B. The incus (ear bone) vibrates

C. The hair cell releases neurotransmitter

D. Pressure waves pass through the air in the ear canal

E. Afferent neurons transmit action potentials through the cochlear nerve

F. The hair cell membrane is depolarized

G. Pressure waves travel through the fluid in the cochlea

H. The tympanic membrane vibrates

I. Voltage-gated Ca2+ channels open

J. The stapes (ear bone) vibrates

K. Stereocilia in hair cells deflect (bend)

L. The malleus (ear bone) vibrates

M. The oval window vibrates

Answer 1

Answer :

The process of hearing can be shortly summarised as follows. Sound vibrations are picked up by pinna (extra ear) which passes through ear canal to the middle ear. Midlle ear contains three small ear bones, which increase the magnitude of vibrations. The vibrations are sent to inner ear, cochlea. Cochlea has special hair cells which converts pressure variation (sound) into electrical signals. These signals are sent to brain via auditory nerve, and the brain processes electrical signal which we percieve as sound.

The steps can be organised as :

D. Pressure waves pass through the air in the ear canal.

H. The tympanic membrane vibrates.

L. The malleus (ear bone) vibrates.

B. The incus (ear bone) vibrates.

J. The stapes (ear bone) vibrates.

M. The oval window vibrates.

G. Pressure waves travel through the fluid in the cochlea.

K. Stereocilia in hair cells deflect (bend).

A. K+ channels in the hair cell membranes open.

F. The hair cell membrane is depolarized.

I. Voltage-gated Ca2+ channels open.

C. The hair cell releases neurotransmitter.

E. Afferent neurons transmit action potentials through the cochlear nerve.