Ear | The Process of Hearing | How Ears maintain the Balance of body

 Hearing is as important as vision. Our ear helps us in hearing and also to maintain the balance or equilibrium of our body . Ear has three main parts,

Ear

> External Ear

> Middle Ear 

> Inner Ear

1  External Ear

External ear consist of pinna, auditory canal and ear drum. Pinna is the broad external part, made of cartilage and covered with skin. It helps to direct sound waves into auditory canal. There are special glands in the walls of auditory canal, which produce wax. The wax and the hairs in auditory canal protect ear from small insects, germs and dust. In additions to this they help to maintain the temperature and dampness of auditory canal. Auditory canal ends in ear drum. This thin membrane separates external ear from middle ear.

2  Middle Ear 

Middle Ear 

Middle ear is a chamber after external ear. Three small bones called middle ear ossicles are present in chain in middle ear. these movable bones include with ear drum then comes incus and finally stapes that is connected with a membrane called oval window separates middle ear from inner ear. Middle ear also communicates  with the nasal cavity through eustachian tube . This tube regulates the air pressure on both side of ear drums.

3 Inner Ear 

Inner Ear 

Inner ear consist of three parts i.e. vestibule semicircular canals and cochlea. Vestibule is present in the centre of inner ear. Three canals called semicircular canal are posterior to the vestibule. The cochlea is made of three ducts and wraps itself into a coiled tube. Sound receptor cells are present within the middle ducts of cochlea.

The Process of Hearing

The pinna of the external ear focuses and directs sound waves in to auditory canal. The sound waves strike ear drum and produce vibration in it. From ear drum the vibrations strike middle ear and produce further vibration in malleus incus and then stapes. From stapes the vibration strike the oval window and then reach the fluid filled middle duct of cochlea. The fluid of cochlea is moved and receptor cells are stimulated. The receptor cells generated a nerve impulse, which travels to brain and is interpreted as sound.

How Ears maintain the Balance of body ?

Semicircular canals and vestibule helps to maintain the balance of body. semicircular canal contain sensory nerves which can detect any movement of head. Vestibule can detect any changes in the posture of body. Th neurons coming from these two receptors reach cerebellum through the auditory nerve.