Vision, Lab 7 and hearing

The organ of hearing is the ear; it has outer, middle and inner parts. The outer ear includes the auricle, which collects sound, and the ear canal leading inward; the end of the canal is closed by the thin eardrum. In the middle ear three ossicles – the malleus, incus and stapes – amplify sound vibrations and pass them to the inner ear; the middle ear connects to the pharynx through the auditory tube, which equalises pressure. The inner ear has a fluid-filled cochlea, whose hair-cell receptors convert vibration into nerve impulses; impulses go along the auditory nerve to the temporal cortex, where sound is perceived. With two ears we find which direction a sound comes from. Hearing hygiene: keep the ear clean but do not push sticks, hairpins or sharp objects inside – the eardrum can be damaged; if too much earwax reduces hearing, see a doctor; if water gets into the ear tell adults; for ear pain, discharge or fever do not use drops or heat on your own. Do not turn headphone volume high (no more than about half of maximum), do not wear them for a long time, and protect the ears in noisy places. If a foreign object gets into the ear, do not try to remove it – go to a doctor.