SCIENCE03L02: The Ears

OBJECTIVES  Identify the sense organ used for hearing  Name the parts of the ear and describe the functions of each part  Describe how sound waves travel through the ear  Cite common ear problems and their causes  Cite ways on how to care for the ears LESSON PREREQUISITE None. LESSON PROPER The Ears as Organs for Hearing The ears are our sense organs for hearing. They have three main parts: the outer ear, the middle ear, and the outer ear. These parts work together to let us hear sounds.. The Outer Ear The outer ear includes the earflap and the ear canal. The earflap, also called pinna or auricle, receives o captures sound waves. At the center of the pinna is the ear canal. It is a bony passageway connecting the outer ear to the middle ear. It is where the captured sound waves travel. The ear canal is lined with glands that secrete a yellow, waxy substance called cerumen or earwax. The cerumen lubricates the ear and protects it from dirt and bacteria. At the end of the ear canal is the tympanic membrane or eardrum. It separates the outer ear from the middle ear. The eardrum vibrates when sound reaches it. The Middle Ear The middle ear is a tiny space filled with air. It has three tiny bones that are linked together, the hammer, anvil, and stirrup. These bones, collectively called ossicles, are connected to the eardrum. The hammer or malleus is attached to the eardrum on one end and to the anvil or incus on the other end. It picks up the eardrum’s vibrations and transmits them to the anvil. The anvil or incus receives the vibrations from the hammer and transmits these to the stirrup. The stirrup or stapes is attached to the inner ear through an opening called oval window. The middle ear has another opening called the round window, through which the tympanic membrane or eardrum communicates. The Inner Ear The inner ear consists of two main parts, the cochlea and the semicircular canals. The cochlea is the hearing part of the inner ear. It looks like a snail shell and is filled with watery fluids. These fluids move when they pick up vibrations from the ossicles in the middle ear. The movement of these fluids makes the tiny hairs in the cochlea move up and down. This movement creates a signal which is sent to the brain. The brain then interprets this signal into a sound that we recognize, causing us to hear the sound. The semicircular canals have organs that help us keep our sense of balance. The Eustachian tube, which is the narrow tube that connects the middle ear to the back of the throat, helps to balance the air pressure on each side of the eardrum. Common Ear Problems Deafness is one of the common ear problems that we may experience if we do not take care of our ears properly. Deafness is the loss of hearing caused by an injury or issue in the middle or inner ear, such as buildup of fluid or ear wax. Ear boil is an infection of the outer ear characterized by swelling, redness, and pain. Ear infection is an infection of the middle or outer ear. It is characterized by severe pain in the ear and a milky ear discharge with unpleasant odor. Earache can be a sharp, dull, or burning pain in one or both ears. It may be caused by impacted earwax, sinusitis, or prolonged exposure to loud noise. How to Take Care of Your Ears Your ears are as important as your other sense organs. This is why you should take care of them. Here are some ways of taking care of your ears. 1. Clean your ears with a cotton bud or a clean cloth to prevent infections. Never use pointed objects, like hairpins, in cleaning them. Doing so can damage your eardrum. The best time to clean your ears is after taking a bath, while the cerumen is still soft. 2. Avoid listening to loud sounds. Loud sounds can damage your eardrums which can lead to loss of hearing. 3. Immediately consult an ear doctor when an insect or a small object gets into your ear.