We are able to experience the world around us in different ways. We can feel touch, feel hot or cold. We can see, hear, smell the things around us. We are able to taste the food we eat.
In this lesson, we are going to learn about our SENSES and our SENSE ORGANS. We will try to understand:
A sense means a way that the body perceives external stimuli. The senses help us to experience the world around us and protect us from various dangers. We use our sense of sight and hearing to see and hear. The senses of smell and taste allow us to enjoy our food, and we can feel through touch. Our five senses are controlled by the brain. Humans have five basic senses and each of them is very important. They are:
1. Sense of sight
2. Sense of hearing
3. Sense of smell
4. Sense of taste
5. Sense of touch
Each sense is connected to our specific organ. So, humans have the following sense organs:
1. Two eyes (Sense of sight)
2. Two ears (Sense of hearing)
3. Nose (Sense of smell)
4. Tongue (Sense of taste)
5. Skin (Sense of touch)
Humans have two eyes. With our eyes, we can identify objects around us. We need our eyes to see. A good sense of sight is achieved by a healthy eye. Sight, or perceiving things through the eyes, is a complex process. Light enters the pupil of the eye. The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil. The image is projected upside down, and the brain rolls over to see it properly.
People have different eye colors. They can be brown, green, blue, and all of them can appear in many shades. People whose two eyes are of different colors can also be found in the world. This phenomenon is rare and is called heterochromia.
We need to protect our eyes, be careful not to hurt them.
Nutrition can improve our eyesight. This is especially true if we eat carrots.
We listen with our ears. Humans have two ears. The ear is not only what we see from the outside. The ear is made up of three parts: the outer ear, middle ear, and inner ear. With our ears, we detect sounds, voices, noises. The sound waves travel through the air and reach the ears.
A sound wave is a pattern of disturbance that can be caused by the movement of energy that travels through a transmission medium such as a gas, liquid or solid. It is the form that sound takes when it passes through the air, water, etc.
Sound is the reception of such waves and their perception by the brain. The loudness of sound is measured in decibels (dB), and if we hear a loud sound for a long time, it can damage our hearing.
The nose is an initial part of the respiratory system and contains odor sensors. There are numerous nerve endings in the back of the nose. When fragrant particles reach that part they cover the nerves and thus generate impulses that travel through the nervous system. So we get information about the type and quality of the aroma.
Humans can detect even more than 1 trillion different odors. The odors can be good and bad. Some of them we like, some of them we don’t like. A number of studies have shown that the odors that people like make them feel good, whereas odors people dislike are making them feel bad.
The tongue is a muscular organ in the mouth. Different parts of the tongue have sweet, sour, savory, and bitter flavors. The tiny bumps on the tongue are called taste buds. The surface of the tongue is made up of about ten thousand taste buds, which can detect only five chemical stimuli: sour, bitter, sweet, salty, and umami. Each taste bud has about 100 receptor cells which send a signal to the brain through the nerve fibers located on them.
By detecting these chemical stimuli the tongue can protect us from taking in toxic substances, or we can recognize some food that is not good for consumption.
The skin is the body's largest organ. It covers the entire body. It serves as a protective shield against heat, light, injury, and infection. It is responsible for the sense of touch.
When we touch something, reception cells send a message to the brain through the sensory nerves. The brains interpret those messages and make us respond appropriately to what we touch. The network of receptors in our skin is forming our body's largest sensory system. Because there are so many sensory nerves, we can feel even the lightest touch. Our sense of touch allows us to tell if something is hot or cold, rough or smooth, wet or dry.
In order to react and communicate, our brain must receive and process information about the world outside. As the sensory organs: the eyes, ears, nose, tongue, and skin help us connect with the outside world, they have sensory receptors that receive the stimuli and translate them into signals. These signals are sent by nerves to the brain, which interprets them as sight, sound, smell, taste, and touch and then helps the body to react to external stimuli.
All the sense organs of our body make our life easy and comfortable. Sense organs are a vital part of our body and we must take good care of them. Few caring tips are given below:
