In the human ear, where are the sensory receptors responsible for hearing (the organ of Corti) located?

Introduction / Context:
Hearing involves converting sound waves into nerve impulses that the brain can interpret. This question focuses on the anatomical location of the receptors for hearing. Knowing where the organ of Corti is located helps you understand how the inner ear functions and how different parts of the ear contribute to hearing and balance.

Given Data / Assumptions:
• The ear has three main parts: outer ear, middle ear, and inner ear. • The organ of Corti is the sensory structure for hearing. • Different inner ear structures have different roles in hearing and balance.

Concept / Approach:
The inner ear contains the cochlea, vestibule, and semicircular canals. The cochlea is a spiral shaped, fluid filled structure that houses the organ of Corti. Within the organ of Corti, hair cells act as mechanoreceptors that convert mechanical vibrations of the basilar membrane into electrical signals. These signals travel via the auditory nerve to the brain. The vestibule and semicircular canals are mainly involved in balance and equilibrium, not in hearing. The tympanic membrane and ossicles are involved in conducting and amplifying sound but do not contain the primary hearing receptors.

Step-by-Step Solution:
Step 1: Recall the pathway of sound: external ear collects sound, tympanic membrane vibrates, ossicles transmit vibrations to the inner ear. Step 2: Note that the stapes pushes on the oval window, creating waves in the fluid of the cochlea. Step 3: Within the cochlea, the organ of Corti sits on the basilar membrane and contains hair cells. Step 4: These hair cells transduce mechanical vibrations into nerve impulses in the auditory nerve. Step 5: Therefore, identify the cochlea as the structure that contains the receptors for hearing.

Verification / Alternative check:
Standard diagrams of the inner ear clearly label the cochlea as the coiled part associated with hearing and the semicircular canals as looped structures associated with balance. The organ of Corti is drawn inside the cochlea and is never placed in the vestibule, middle ear, or semicircular canals. This confirms that the cochlea is the correct location.

Why Other Options Are Wrong:
Option A: The vestibule is associated mainly with static balance and position of the head, not the primary receptors for hearing. Option B: The tympanic membrane is the eardrum that vibrates in response to sound but does not contain the sensory cells for hearing. Option C: The semicircular canals detect rotational movements of the head and contribute to dynamic equilibrium, not hearing. Option E: The auditory ossicles (malleus, incus, stapes) amplify and transmit vibrations but do not themselves act as receptors.

Common Pitfalls:
Students sometimes confuse structures involved in sound conduction with those that actually detect sound. It is important to separate the roles: outer and middle ear conduct and amplify sound, inner ear structures convert sound to nerve impulses. Another common error is to confuse the semicircular canals and cochlea because they are both in the inner ear. Remember that cochlea is associated with hearing, while semicircular canals are associated with balance.

Final Answer:
The receptors for hearing are located in the cochlea, which contains the organ of Corti.