Understanding Eye and Ear Functionality for Better Health

How the Eye Works

Regulation of Light Intensity

The pupil opens more or less depending on the intensity of the light. It does this through the contraction or relaxation of very small muscles located in the iris.

Focusing Images

This happens thanks to the modification of the thickness of the lens by muscles in the ciliary body. The lens is flattened to focus on distant objects and it bulges when objects are near. A normal eye can focus well on objects that are between 15 centimeters and 65 meters away.

The Ear

Parts of the Ear

Outer Ear

This is made up of the pinna and the ear canal, which penetrates the bone. In the canal, there are glands that produce protective wax. The ear canal ends in the tympanic membrane, also called the eardrum.

Middle Ear

This is a cavity in the temporal bone which starts at the eardrum and reaches two small membranes called the oval window. There are three small connected bones in this part of the ear: the malleus, the incus, and the stapes. The hammer is joined to the eardrum and the stirrup to the oval window.

Inner Ear

This is the deepest part of the ear and is made up of labyrinthine membranes. These form two complicated cavities in the temporal bone. There is a fluid called perilymph between the two labyrinth cavities, and within the membranes, there is another liquid called endolymph. The first part of the labyrinth is the cochlea, which is responsible for picking up sounds. The other, the vestibule, is responsible for spatial control and balance. The vestibule is made up of three channels or semicircular canals and two vesicles called the utricle and the saccule.

How is Hearing Produced?

Sound waves (vibrations) reach the eardrum, making it vibrate, transmitting the vibration through the three bones of the middle ear, which transfer it to the oval window. This in turn makes the perilymph fluid in the inner ear vibrate, stimulating the interior cells in the cochlea, which make up the organ of Corti. A nerve impulse starts there and travels to the brain, where the information is interpreted.

How is Balance Controlled?

The sense of balance tells us the position of our body and the movements we make. Sight, the mechanoreceptors in muscles and joints, and the touch sensors on the soles of our feet are all involved in this process.