Final answer:
The external ear consists of the pinna, auditory canal, and tympanic membrane, whereas the cochlea is part of the inner ear and is not a term related to the external ear. Disorders can include infections or blockages.
Step-by-step explanation:
The external ear comprises the pinna, which is the part of the ear that captures sound waves, and the auditory canal, ending with the tympanic membrane or eardrum. The external ear is involved in funneling sound waves through the auditory canal towards the tympanic membrane. The eardrum vibrates in response to sound waves, initiating the hearing process. Disorders of the external ear can include infections like otitis externa, blockages due to earwax, and structural deformities.
In contrast, the middle ear contains the auditory ossicles: the malleus, the incus, and the stapes, which amplify and transmit these vibrations to the inner ear. The inner ear houses the cochlea, primarily involved in converting the mechanical energy of sound waves into nerve impulses and maintaining balance. The term cochlea, however, does not pertain to the external ear but to the inner ear. Therefore, the correct answer is: