Our sense organs
We are sensitive to the world around us. We can feel when it is cold or warm, we can identify where we are and what is around us. We can recognise people and identify their voices. If fact we are receiving stimuli from the external world every second, awake or asleep, and we have the capability of interpreting these stimuli to derive useful information from them. The sense of sight, hearing, touch, smell, and taste provide us with the sensation of the external world. We have a special organ associated with each sense. The five organs are the eyes, ears, skin, nose, and the tongue.
These organs are just the information gatherers. They receive the external stimulus and pass it on to the main processor - the brain, where it is interpreted. In short, the work of the sense organs is to receive the stimulus and convert them into signals (information carriers). These signals are then passed on to the brain. Each sense organ has its specialized way of converting stimulus to signals.
In man, the sense of sight is the most significant one and 80% of the all information is gathered by eyes. Sometimes, we may lose one or the other sensation temporarily. This is when we begin to appreciate the importance of the sense organs. For instance, the eyes become useless in pitch darkness. If we are in a soundproof room, we don't get to hear anything from the outside and even if someone is trying to say something, we are incapable of understanding them, we cannot smell when we have a bad cold and no food tastes good when we are sick and the tongue is affected.
Some people might have lost one or the other sense organ, usually the eyes or the sense of hearing, in accidents. Some are born without these sensations. In such cases, they learn to use the other sense organs to compensate for the loss. It might not be a complete compensation, but most of what one likes to do can be managed. For example, the blind develop their sense of touch and are in a position to derive almost all information from it, in association with their other remaining senses. Of course there are limitations. They cannot perceive colour - which is one of those sensations only eyes can provide. Similarly, the deaf learn to use their sight. They can lip read to understand what is being said. However, music is beyond them.
A careful thought about what we may have to do if our sense organs stop working would prompt us to take extra care of them. It is also interesting to note that nature has its own way of protecting these important organs. But we need to do our bit too!