Exam 4 Review:  Chapter 15:  External Ear

auricle = pinna - The outer visible projecting portion of the ear, composed of elastic cartilage covered by skin, which functions to collect and focus sound waves on the tympanic membrane.

external auditory meatus = external ear canal - The narrow passage way through which sound waves are transmitted from the auricle/pinna to the tympanic membrane; the outer half is supported by cartilage while the inner half is supported by bone (the temporal bone); the opening is protected by small hairs and cerumen.

cerumen - The secretion of the ceruminous glands, a yellow or orange sticky, bitter, waxy substance which assists in protecting the external ear canal from invasion by ectoparasites (insects).

tympanic membrane = tympanum - The delicate sheet of skin covered connective tissue which forms the boundary between the outer and middle ear; on its medial surface the malleus (hammer) is attached which responds to sound waves causing vibrations by transmitting those vibrations, in a lever system with the other two ear ossicles, to move the membrane of the oval window in order to transmit pressure vibrations into the perilymph of the cochlea; nickname eardrum.

Tympanum and Ossicles of the Middle Ear

Normal Tympanic Membrane Acute Otitis Media (middle ear infection)

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