Final answer:
The nurse would diagram the cochlea as the structure within the inner ear for a poster teaching about the prevention of hearing loss.
Step-by-step explanation:
When developing a poster to teach clients about the prevention of hearing loss, the nurse would diagram the cochlea as part of the inner ear. The cochlea is a snail-shaped, fluid-filled structure that contains the sensory receptor cells (hair cells) of the auditory system. The Eustachian tube, tympanic membrane (or eardrum), and the external auditory canal are essential parts of the ear but are not located in the inner ear; rather they are found in the middle and outer ear, respectively. The cochlea is responsible for transducing sound waves into neural signals that the brain can interpret as sound, making it crucial for hearing and an important focus for teaching about hearing loss prevention.