The part of the ear which contains nerve cells sensitive to sound vibrations is the

Step 1: Analyze the question The question asks which part of the ear contains the sensory nerve cells (receptors) that respond to sound vibrations. In other words, which structure turns vibrations into nerve impulses?

Step 2: Explain the concept Sound travels through the ear in stages:

1. Pinna collects sound waves.
2. Ear canal channels them to the eardrum.
3. Tympanum (eardrum) vibrates.
4. Ear ossicles (malleus, incus, stapes) pass on and amplify the vibrations.
5. Oval window passes the vibrations to the fluid in the inner ear.
6. Cochlea contains the organ of Corti, which has hair cells (sensory receptors). These convert the vibrations into nerve impulses.
7. The auditory nerve carries the impulses to the brain.

Step 3: Check each option

• A. Cochlea: It contains the organ of Corti, with the hair cells that detect sound vibrations. Correct.
• B. Ampulla: This is the swollen base of each semicircular canal. It contains receptors for balance (movement of the head), not hearing.
• C. Tympanum: This is the eardrum. It only vibrates and has no sound-sensitive nerve cells.
• D. Malleus: This is a small bone (the hammer). It transmits vibrations mechanically and has no receptor cells.

Step 4: Answer The correct answer is A. cochlea.

Tip: Remember "Cochlea = Catches sound signals" and "Ampulla = Awareness of balance." Hearing receptors are in the cochlea, and balance receptors are in the semicircular canals (ampulla) and vestibule.