The ear/الأذن /耳(Ěr)

The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of theauditory system.

The word "ear" may be used correctly to describe the entire organ or just the visible portion. In most mammals, the visible ear is a flap of tissue that is also called the pinna and is the first of many steps in hearing. In humans, the pinna is often called the auricle. Vertebrateshave a pair of ears, placed somewhat symmetrically on opposite sides of the head. This arrangement aids in the ability to localize sound sources.

The ear is divided into three components, the outer ear (pinna), the middle ear, and the inner ear. Each component of the ear has its unique functions.

The outer or external ear The external ear consist of two portions, the first being the pinna, the skin covered flabby cartilage of the ear visible on both sides of the head. The basic function of the outer ear or pinna is to protect the eardrum (tympanic membrane). The outer ear also functions to collect sound waves to the eardrum through the ear canal. The second component of the external ear is the auditory ear canal or meatus. There are modified sweat glands that secrete ear wax in the ear canal. If ear wax is excessive, the ear drum can be damaged or lead to blockage of the transmission of sound. Unlike those of animals, human ears are usually of same size. They only grow from infancy up until youth. The outer ear, also called auricles, of animals vary in sizes and breeds. The middle ear The middle ear refers to the hollowed air-filled bony space (tympanic cavity) in the temporal bone of the skull behind the eardrum. It is just separated from the outer ear by the ear drum. There are three tiny bones (auditory ossicles) in the tympanic cavity that vibrates when exposed to sound waves, namely: Malleus – Also known as hammer Incus – Also known as anvil Stapes – commonly called stirrup These bones form a chain around the middle ear and extend to the oval window of the inner ear and their main function is to amplify sound. The middle ear connects to the back of the throat and nose through the Eustachian tube. The Eustachian tube is the auditory openings that we open when we yawn or swallow. The inner ear The inner ear is the most complicated component of the auditory system located into a tiny space of the hardest temporal bone and inaccessible to direct examination or clinical manipulation. The inner ear comprise of three intimately related structures - the cochlea (spiral tube), three semicircular canals and the vestibule (labyrinth). The cochlea is directly responsible for hearing and contains nerves responsible for converting energy vibrations within the inner ear fluid into nerve impulses which can be transmitted to the brain. While the vestibule (labyrinth) and semicircular canals function to maintain balance or equilibrium.

These are the main functions of the ear

Sound detection, hearing allowance, and balance maintenance are the main functions of the ear. Hearing The most basic function of the ear is hearing. The following is the short description of the hearing process: The first step is when the pinna collects external sounds that enter through the meatus or ear canal as sound waves. The ear drum begins to vibrate as these sound waves strikes. These vibrations pass through to the three ossicles of the middle ear (hammer, anvil and stapes) where they are amplified. As the transmission proceeds, the vibrations first hit the hammer, then the hammer pushes the anvil, and the anvil hits the stapes. The vibrations are finally interpreted as sound in the brain after being transmitted and transformed into nerve signals by the cochlea (snail shaped component of the inner ear). This is due to the connectivity of the oval window of the inner ear to the edge of the stapes. When the stapes vibrates, they always transmit the sound vibrations to the inner ear. Mike Tyson  Balance The other important function of the ear is to help maintain balance. Oriented at the right angles to each other are three semicircular canals of the inner ear. Whenever the head is turned or change position, the resulting movement of fluids within these canals help the brain to identify or detect the extent of movement and positioning of the head. In response to gravity, another part of the inner ear sends information to the brain when the head is held still in a stagnant position.