1. STUCTURE and FUNCTION OF EAR, NOSE, AND TONGUE
SENSORY SYSTEM
STUCTURE and FUNCTION OF EAR, NOSE, AND TONGUE

2. OUTER EAR Pinna (auricle) External auditory canal: ear canal Cerumen
Visible ear
Collects sound waves
External auditory canal: ear canal
Cerumen
Ear wax, protects the ear
Tympanic membrane
Ear drum, separates outer and middle ear
See figure pg. 199

3. MIDDLE EAR Cavity in temporal bone
Connects with pharynx by Eustachian tube
Equalizes pressure in the middle ear with outside atmosphere
Bones - transmit sound waves from ear drum to inner ear
Malleus (hammer)
Incus (anvil)
Stapes (stirrup)

4. INNER EAR Cochlea Organ of Corti Semicircular canals
Spiral shaped organ of hearing, contains a membranous tube, the cochlear duct
Which is filled with fluid that vibrates when sound waves are transmitted by the stapes
Organ of Corti
Delicate hairlike cells that pick up vibrations of fluid and transmit them as a sensory impulse along the auditory nerve to the brain
Semicircular canals
Three structures in inner ear that contain liquid set in motion by head and body movements
Impulses sent to cerebellum to help maintain body balance (equilibrium)
See figure pg.200

5. PATHWAY OF HEARING
Sound waves to outer ear (pinna) to external auditory canal to tympanic membrane to ear ossicles (malleus, incus and stapes) to cochlea to auditory nerve to temporal lobe of brain
See figure pg. 201

6. NOSE Smell accounts for 90% of taste
Tissue in the nose, olfactory epithelium, contains specialized nerve cell receptors
Those receptors stimulate the olfactory nerve to the brain
See figure pg. 204

7. TONGUE Mass of muscle tissue
Bumps on surface are papillae, they contain taste buds
Receptors in taste buds send stimuli through 3 cranial nerves to cerebral cortex
See figure pg. 205