Ears and Eyes Flashcards
Pinna (auricle)
Surrounds entrance to the external acoustic meatus; protects opening of canal and provides directional sensitivity
External Acoustic Canal (Meatus)
Canal in the outer ear that leads to the middle ear and ends at the tympanic membrane
Tympanic membrane
Thin, semitransparent sheet; separates external ear from middle ear
Ceruminous glands
Integumentary glands along external acoustic meatus; secretes waxy material to help keep foreign objects out of tympanic membrane and slows growth of micoorganisms in external acoustic meatus
Tympanic cavity
Space inside the middle ear
Pharyngotympanic tube
Permits equalization of pressues on either side of tympanic membrane; encloses and protects three auditory ossicles
Auditory ossicles
-Malleus (hammer)
-Incus (anvil)
-Stapes (stirrup)
-Converts arriving sound waves into mechanical movements; conduct vibrations to inner ear
Inner ear
Found in the petrous portion of the temporal bone; includes:
-Vestibular Apparatus
-Cochlea
Vestibular Apparatus
Detects balanca and is subdivided into the Vestibule and Semicircular Canals
Vestibule
Receptors provide sensations of gravity and linear acceleration
Semicircular canals
Contain semicircular ducts and has receptors stimulated by rotational movements
Cochlea
Contains receptors that detect vibrations perceived as sound to provide hearing
Oval Window
Formed of collagen fibers and is connected to base of stapes. Movement of the stapes creates vibrations within the cochlea
Vestibulocochlear Nerve (VIII)
Innervates the sense of hearing and balance.
-Cochlear branch: innervates hearing
-Vestibular: innervates balance
Palpebrae
Lenses
