The Ear Perry C Hanavan Outer Ear Peripheral

The Ear Perry C. Hanavan

Outer Ear • Peripheral – Outer ear – Middle ear – Inner ear – Auditory nerve • Central – Brainstem – Midbrain – Cerebral

Peripheral

Outer Ear - Pinna

Middle Ear - Tympanum

Middle Ear – Tympanic Membrane

Middle Ear – Ossicles

Middle Ear - Ossicles

Middle Ear – Ossicles - Malleus

Middle Ear – Ossicles - Incus

Middle Ear – Ossicles - Stapes

Middle Ear

Inner Ear - Osseous

Inner Ear - Membranous

Inner Ear - Labyrinth

Inner Ear – Organ of Corti

Cochlear Structures

Inner Ear – Organ of Corti

Basilar Membrane • Traveling wave

Inner Ear – OHC & IHC • IHC – Non-motile – Afferent – Responds to loud sounds • OHC – Motile – Efferent – Responds to soft sounds

OHCs

Two Theories of Motility • Somatic prestin motor • Hair bundle motor

Tip-links –Hair Bundle Motor <<<IHC OHC >>>

Tip Link Structure • Tip Link Structure

Hair Bundle Motor

Tip-links

Auditory Nerve

2 Types of Auditory Neurons Paul Fuchs You. Tube Type II

Standard ABR Cross-section of Internal Auditory Canal Sup. Vest Nerve Facial Nerve HIGHFREQUENCY FIBERS Acoustic Nerve Large Tumor Abnormal Standard ABR TUMOR The wave V latency used in the standard ABR IT 5 and I-V delay measures is dominated by neural activity from the high-frequency regions of the cochlea. Thus, unless the tumor affects these high-frequency fibers sufficiently, standard ABR latencies will be normal. Inf. Vest Nerve Small Tumor Abnormal Standard ABR Small Tumor Normal Standard ABR