Question

Which is FALSE about efferent connections in the cochlea?

a. They mostly contact inner hair cells

b. They mostly contact outer hair cells

c. They contact a diffuse number of outer hair cells

d. They can cause outer hair cells to change length

e. All of the above are TRUE

Which of the following is/are FALSE?

a. “Sound waves” are made of compressions and rarefactions

b. Sound intensities between 65 and 120 dB are considered painful

c. Room noise ~ 40-50 dB

d. Complex sounds are made up of pure tones.

e. None of the above

About how many Afferents (not Efferents) contact a given inner hair cell (not an outer hair cell)?

a. 1

b. 10

c. 100

d. 1,000

e. 3,000

Speech sounds are mostly in what frequency range?

a. 20 – 20,000 Hz

b. 0 – 120 Hz

c. 1000 – 6000 Hz

d. 1000 – 20,000 Hz

e. 40 – 50 Hz

Which is/are TRUE?

a. Auditory tuning curves are similar to receptive fields that we discussed for touch and vision, except auditory tuning curves are based on frequency, not a map of spatial locations (like in vision and touch).

b. Hair cells and auditory nerve fibers have “V” shaped tuning curves.

c. Auditory tuning curves are broad in the superior colliculus (the nucleus that guides orientation reflexes) and narrow in the inferior colliculus (the nucleus that processes the meaning of sounds).

d. All of the above are True

e. None of the above are True

Answer 1

There are two types of hair cells in the cochlea. They are inner hair cells and outer hair cells. Inner hair cells are present in one row and outer hair cells are present in three rows. Inner hair cells are the actual sensory receptors.

The efferent axons of the cells that arise from the brain terminate mostly on outer hair cells.
Hence option “a” is the correct answer.

Sound waves are made up of compressions and rarefactions. The normal room noise is 45-50 dB. Complex sounds are made up of two or three pure tones.
The sound waves that are above 130 decibels only are painful, but not just above 65 decibels.
Hence option “b” is the correct answer.

Inner hair cells are contacted by around 10-20 afferent neurons.
Hence, option “b” is the correct answer.

The sound waves below 20Hz are called infra sound and the sound waves above 20,000 Hz are called ultra sound waves. The sound waves in the range of 20 – 20,000 Hz are the normal speech sounds.
Hence, option “a” is the correct answer.