Almost all humans are born with five different senses. Your senses are basically defined as methods of perception. The five senses include smell, taste, touch, sight, and hearing. When all of the senses work together, they give people better perceptions, however there are some people that do not have all five of their senses. When someone is missing one of their senses, the ones that they do have become more perceptive and try to make up for the sense that does not work.
Your sense of smell is referred to as olfaction. A humans ability to smell is very important, an our olfactory system is able to differentiate between more than 10,000 different odors. Scientists have made great advances in figuring out how a humans sense of smell works. Every time you breathe, you inhale air into your nostrils, the air passes through your nasal cavity and into your olfactory system, which is packed with millions of receptor neurons. Every time you inhale, and air hits the receptor neurons, odor molecules are picked up by little hairs called cilia which are located on the neuron receptors. The receptors then send a signal to the brain, which is able to process what you are smelling, whether it be perfume, or cookies in the oven. There are a small percentage of people that have no sense of smell at all, and those people have a disorder called Anosmia. Anosmia generally results from damage to the olfactory senses.
SOSI – the Sense of Smell Institute
Sense of Smell – an article explaining how the sense of smell works
Chemosensory Disorders - a list of common smell and taste disorders
Taste is another of the five senses, and is very much related to your sense of smell. We are able to taste with the use of taste buds which are located on the tongue. The taste buds along with taste receptor cells located in your mouth can distinguish between sweet, sour, salty, and bitter. People that suffer from Anosmia have a harder time tasting things because your sense of smell and taste are connected. Being able to smell an odor helps your taste buds to ultimately work better.
Physiology of Taste – an explanation of how the sense of taste works
Taste Disorders – information from the National Institute of Health about common taste disorders
While most of our senses are located in one specific part of the body, the sense of touch is different. A persons sense of touch allows them to distinguish between soft and hard, wet and dry, and rough and smooth among others. Unlike the other senses, touch can be felt all over the body. We have millions of nerve endings in our skin that react to touch by sending a signal to the brain. Some parts of the body have more receptors than others which makes those parts of the body more sensitive to touch.
Sense of Touch - how the nervous system works with our sense of touch
Skin & Touch - a lesson plan to teach about how the skin responds to touch
A persons sense of sight may be one of the most important sense we have. When a person uses their eyes to look at something, they are actually seeing beams of light which are bouncing off the object you are looking at and into your eyes. The image is then sent to your brain for processing, as well as storage, that way you can remember the image at a later time. Not everyone can see well, so the use of glasses or contact lenses are a possibility.
Eye Anatomy & Function - an explanation of how our sense of sight works
How The Eye Works - information and an illustration of how our eyes work
The last of the five senses is your sense of hearing. Peoples ears are designed to channel sound into the ear drum. When an object makes a noise it causes a vibration which travels into your middle ear, and then hits your ear drum causing it to slightly vibrate. This sets off a kind of chain reaction, and the vibration is changed into a message which is sent to the brain to decipher the sound. Problems with hearing can possibly be corrected with the use of a hearing aid.
How the Ear Works - a great explanation with pictures of how we hear
Sense of Hearing - the different parts of the ear and how they work to help us hear
Our five senses can work independently but their ultimate goal is to work together to give us a good sense of perception. There are many different disabilities and disorders that can causes any of your senses to stop functioning properly, and while some can be corrected there are others that cannot. When a person is missing one of their senses, the other senses work even harder to compensate for the one that isn't functioning.