26. Hearing and vision
Hearing
The ears are organs that are used to hear things.
The ear lobes collect sound waves from the environment and direct them towards the ear. The sound waves travel through the auditory canal into the eardrum. The eardrum is a reverberating structure that enhances the volume of the sound waves. From there, the enhanced sound waves travel through the auditory ossicles into the cochlea of the inner ear. The receptor cells in the cochlea sense the sound waves, and the sensation is transmitted by auditory nerves into the auditory area of the brain's cerebral cortex.
The receptor cells of the inner ear cannot regenerate. This is why it is important to protect your hearing from loud noises, for example when attending a concert.
The vestibular organs are also located in the inner ear. They give us information about the head's position and movement, even if we kept our eyes closed.
Vision
We sense visual information with our eyes. The eyes are mostly protected by the skull, leaving only a small part of them visible. The visible parts of the eye include the translucent cornea, the colorful iris and the dark, central part of the eye's lens known as the pupil. The lens reflects light and can be controlled by the eye's muscles. This makes it possible for us to focus on objects at different distances.
The visual information is reflected into the eye's retinas. From there, the visual information travels to the brain via the visual nerve. The function of the iris is to regulate the amount of light that is absorbed by the eye.
The function of the eye's lens can be improved with eyeglasses. For example, many people over 50 experience difficulties in looking at things that are close to them. This is caused by the fact that the lens' ability to reflect light decreases as a peson ages. This can be fixed with eyeglasses that help the lens to reflect life more efficiently.
The eyes are sensitive organs that should be protected. Small particles of dust, chemicals and solar radiation are all harmful to your eyes. This is why the eyes should be protected with sunglasses when spending a lot of time outdoors during the summer. Similarly, staring at a computer screen for long periods of time will tire your eyes out.
The visual information is reflected into the eye's retinas. From there, the visual information travels to the brain via the visual nerve. The function of the iris is to regulate the amount of light that is absorbed by the eye.
The function of the eye's lens can be improved with eyeglasses. For example, many people over 50 experience difficulties in looking at things that are close to them. This is caused by the fact that the lens' ability to reflect light decreases as a peson ages. This can be fixed with eyeglasses that help the lens to reflect life more efficiently.
The eyes are sensitive organs that should be protected. Small particles of dust, chemicals and solar radiation are all harmful to your eyes. This is why the eyes should be protected with sunglasses when spending a lot of time outdoors during the summer. Similarly, staring at a computer screen for long periods of time will tire your eyes out.
Other senses
In addition to hearing and vision, humans also use many kinds of other senses. The most important of these senses are the senses of taste and smell. We use these senses to receive information about the food we eat and the environment we inhabit.
The receptor cells in your skin are also important. They sense things such as cold, heat and pressure.
Terminology
| Term | Explanation |
|---|---|
| ear | An organ that processes sound waves and aural information. |
| eye | An organ that processes light and visual information. |
| sense | A human's ability to reeive information about their environment. |