THE EYE AND THE EAR

The pathways into the orbit are the
1)
2) Superior
3) Inferior

The order of the auditory ossicles is

1.
2.
3.

THE PASSAGE OF SOUND THROUGH THE OUTER EAR

The directs sound waves towards the . At the end of the EAM it hits the membrane. High pitched sounds cause it to vibrate . Low pitched sounds cause it to vibrate . Sound waves are converted to vibration.

THE PASSAGE OF SOUND THROUGH THE MIDDLE EAR

The of the middle ear transmit the vibrations to the inner ear. The tympanic membrane attaches to the - the largest auditory ossicles. The is the middle ossicle. The is the third ossicle (it is also the smallest bone in the human body). The stapes attaches to the , which separates the middle and inner ear. The vibrates times more vigorously than the tympanic membrane because the auditory ossicles transmit the vibrations efficiently.

PASSAGE OF SOUND THROUGH THE INNER EAR

Vibrations at the round window causes the movement of perilymph at the . Pressure waves through the inner ear. The pressure waves cause within the cochlea duct to move. This causes the (hair-cells) to bend which generates nerve .

NERVE IMPULSE PRODUCTION IN THE INNER EAR

When the bend it allows endolymph to enter. The endolymph is rich, which causes an energy potential. A neurotransmitter is then released which generates a nerve in sensory neurons of the hair.

The impulse is passed along the cranial nerve. From here, it goes to the cochlear nuclei in the medulla oblongata. It then passes to the midbrain and thalamus, eventually reaching the PRIMARY AUDITORY AREA in the temporal lobe of the cerebral cortex.