Our senses allow us to learn, to protect ourselves, to enjoy our world. Can you imagine what it might be like to live your life without any of your senses? The senses usually work together to give us a clear picture of the things around us. If one sense is not working due to an accident or illness, then other senses will take over or become stronger to make up for the missing sense.
The five senses are: taste, sight, touch, smell, and hearing.
Taste
Our sense of taste comes from the taste buds on our tongue. These buds are also called papillae. But, the sense of smell also affects our taste.
The tongue is only able to taste four separate flavors: salty, sweet, sour and bitter. But, you might ask, how come different sweet foods taste different if there are only four flavors? That's because your favorite candy might be a combination of sweet and salty. And the chips in your chocolate chip cookie could be a combination of sweet and bitter. Everything you taste is one or more combinations of these four flavors.
Not only can your tongue taste, but it also picks up texture and temperature in your food like creamy, crunchy, hot or dry.
Your tongue is also one of the strongest muscles in your body and is able to heal from injury more quickly than other parts of your body. We also need our tongue to produce certain sounds when we speak.
Sight
Our sense of sight is all dependent upon our eyes. A lens at the front of the eyeball helps to focus images onto the retina at the back of the eye. The retina is covered with two types of light sensitive cells – the cones and the rods. The cones allow us to see color and the rods allow us to see better at night and also aid us in our peripheral vision. All of this information is sent to the brain along the optic nerve.
The images sent are actually upside down and our brain makes sense of what it receives by turning the image right side up. The brain also uses the images from two eyes to create a 3D (three dimensional) image. This allows us to perceive depth.
Some people are not able to tell red colors from green colors. This is called color blindness. Others, through injury or other conditions, have little to no sight at all.
Touch
The sense of touch is spread through the whole body. Nerve endings in the skin and in other parts of the body send information to the brain. There are four kinds of touch sensations that can be identified: cold, heat, contact, and pain. Hair on the skin increase the sensitivity and can act as an early warning system for the body. The fingertips have a greater concentration of nerve endings.
People who are blind can use their sense of touch to read Braille which is a kind of writing that uses a series of bumps to represent different letters of the alphabet.
Our skin is the largest organ in our body and contains the most nerve endings.
Are some areas of your skin more sensitive to touch than others?
Smell
Our nose is the organ that we use to smell. The inside of the nose is lined with something called the mucous membranes. These membranes have smell receptors connected a special nerve, called the olfactory nerve. Smells are made of fumes of various substances. The smell receptors react with the molecules of these fumes and then send these messages to the brain. Our sense of smell is capable of identifying seven types of sensations. These are put into these categories: camphor, musk, flower, mint, ether, acrid, or putrid. The sense of smell is sometimes lost for a short time when a person has a cold. Dogs have a more sensitive sense of smell than man.
In addition to being the organ for smell, the nose also cleans the air we breathe and impacts the sound of our voice. Try plugging your nose while you talk.
Smell is also an aide in the ability to taste.
Hearing
Our ears, which help us hear, are made of three separate parts: the outer ear, the middle ear and the inner ear. The outer ear is the part that others see. It works like a cup to catch sound as it travels past our heads. This part is made of cartilage and skin. From here, sound travels to the tympanic membrane and then onto the inner ear via the three smallest bones in your body. The inner ear is also called the cochlea and is a spiral shaped tube which translates vibrations into sound and sends that message to the brain through the auditory nerve. The brain uses the sounds from both the left and the right ear to determine distance and direction of sounds.
Some people who are unable to hear rely on sign language for communication. This is done by using their hands and body language to communicate with others.
Additional Senses
In addition to sight, smell, taste, touch, and hearing, humans also have the sense of balance, pressure, temperature, pain, and motion. These various "new" senses all work together and may involve the coordinated use of the sense organs. The sense of balance is managed by a complicated network of various body systems. Any quick change to any of the five senses can cause the feeling of dizziness or unsteadiness. You might have experienced this while riding in a car or turning quickly.
Give This a Try
This is your opportunity to try an experiment with your senses. You will need:
something you enjoy eating – maybe an apple or banana
an onion, cut open (adults should do the cutting)
Now, get someone to help you, by holding the onion under your nose while you eat the apple or banana. Take a deep breath and chew. What do you notice? Some of our enjoyment of eating comes from the fragrances of the food.
What foods do you enjoy smelling? Fresh baked cookies? Bacon frying? Some fragrances will even bring back strong memories.
