NUR1 239 Chapter Notes - Chapter 15: Eardrum, Semicircular Canals, Conductive Hearing Loss
Document Summary
Includes : auricle/pinna, external auditory canal, tympanic membrane/ eardrum. 2. 5 cm (1 in. ) long in adult ; ends at the tympanic membrane. Covered w/ skin that has many fine hairs, glands, and nerve endings. Glands secrete cerumen (earwax) w/c lubricates and protects ear canal. Curvature differs w/ age : upward curvature in infant and toddle , An air- filled cavity that starts at the tympanic membrane. Contains three ossicles (bones of sound transmission : malleus (hammer, incus (anvil, stapes (stirrups) Connects the middle ear to the nasopharynx. Stabilizes the air pressure bet. the external atmosphere and middle ear thus preventing rupture of the tympanic membrane and discomfort produced by marked pressure differences. Contains : cochlea a seashell-shaped structure essential for sound transmission and hearing, vestibule, semicircular canals contains the organs of equilibrium. Sound can be transmitted by : air conduction, bone conduction. Occurs when skull bones transport sound directly to the auditory nerve.
