special sense: hearing and equilibrium Flashcards
• External Ear
o Composed of the auricle and external acoustic meatus
• Auricle (pinna)
o The skin covered cartilaginous structure encircling the auditory canal opening
• Lobule
portion of the pinna lying inferior to the external auditory canal
• External Acoustic Meatus (external auditory canal)
short narrow chamber carved into the temporal bone
• Ceruminous Glands
o Skin lined walls in the external acoustic meatus that secrete wax
• Tympanic Membrane( Eardrum)
o Where sound wave enter that vibrate at exactly the same frequency as the sound waves hitting it
• Middle Ear
o A small chamber, tympanic cavity, found within the temporal bine
• Auditory ossicles
o Malleus, incus, stapes
o Articulate to form a lever system that amplifies and transmits the vibratory motion of the eardrum to the fluids of the inner ear via the oval window
• Pharyngotympanic (auditory) tube
o Connects the middle ear chamber with the nasopharynx
• Otitis Media
o Inflammation of the middle ear
• Internal Ear
o A system of bony and rather tortuous chambers called the bony labyrinth
• Bony Labyrinth
o Filled with perilymph
o Cochlea, vestibule, semicircular canals
• Perilymph
o Aqueous fluid in the bony labyrinth
• Vestibule
o Involved with equilibrium
• Semicircular Canal
o Involved with equilibrium
• Cochlea
o Contains sensory receptors for hearing
• Cochlear duct
o Soft, wormlike tube about 3.8 cm long
o Separates the perilymph containing cochlea cavities into upper and lower chambers
• (Middle) Scala media
o Cochlear duct
o Filled with endolymph
o Supports the spinal organ
• Spinal Organ
o Contains the receptors for hearing
o Sensory hair cells and nerve endings of the cochlear nerve(vestibulocochlear nerve(VIII))
• Basilar Membrane
o Forms the floor of the cochlear duct
• Tectorial membrane
o Gelatinous membrane that stereocilia hairs project into
• Hair cells
o Receptors that monitor head position and acceleration in a straight line
• Otolith
o small grains of calcium carbonate
