Can you smell things from a distance?
Close your eyes and fell something. Are you able to recognize them? How do yo recognize them?
You remember things that you have seen before, sounds you have heard before, and food you may have eaten earlier. The eyes, ears, nose, tongue and skin are your sense organ. Do the sense organ remember things? No, the sense organ only gather information from the surroundings. It is the nervous system that helps you to remember things.
What is nervous system?
Everything you do is controlled by your nervous system, including breathing, walking, thinking, and feeling. This system is made up of your brain, spinal cord, and all of your body’s nerves. The nerves transport messages to and from the body, allowing the brain to interpret and act on them.
What are present in nervous system?
The brain, the spinal cord and nerves that are present in all parts of the body form the nervous system.
THE BRAIN: The brain controls most functions of the body. It tells every part of your body what to do, even when you are asleep. the brain soft and delicate like jelly. It is protected within the bony structure called skull. the space between the brain and the skull bones is filled with a fluid.
The brain has three main parts—cerebrum, cerebellum and medulla.
*Cerebrum: The cerebrum is the largest part of the brain. It helps you to think, remember and learn. It also controls the functions of the sense organs.
*Cerebellum: The cerebrum controls muscular activity and maintain the balance of the body.
*Medulla: The medulla is the lowermost part of the brain. The spinal cord begins at the medulla. The medulla regulates functions such as the heartbreaks, circulation of blood and breathing.
THE SPINAL CORD: The brain is not the only organ that controls the function of the body. The spinal cord which is connected to the brain controls some of the functions. It begins at the lower part of the brain and is protected inside the vertebral column.
The vertebral column is a flexible tube like column made up of 33 column bones. It runs all along your back. The spinal cord links several parts of the body to the brain.
The brain and spinal cord together control all the functions of the body. All the movements of the body are controlled directly by either the brain or through the spinal cord.
How are the brain and the spinal cord connected to the different parts of the body?
The brain and spinal cord controls the functions of the body because they receive information from the body and also send messages to the various parts of the body. If you accidentally step on a throne, you feel the pain. You then quickly move your leg away from the thorn.
How does it happens?
This done through the nerves. Nerves are present in the entire body.as soon as you step on a thorn, the nerves in your foot transmit a message to the spinal cord and the spinal cord immediately sends back a message to the leg to move away.
Most of the nerves which begin in different parts of the body meet the spinal cord. The spinal cord joints the nerves from various parts of the body with the brain. Some nerves directly connect the organ and the brain without meeting the spinal cord. the eyes and the nerves have such spinal cord.
How many types of nerves are there?
There are three types of nerves—sensory, motor and fixed type of nerves.
*sensory nerves carry message from the sense organ to the brain or spinal cord.
*The motor nerves carry messages from the brain or spinal cord to the sense organ.
*the mixed type of nerve carries messages both the ways, from the sense organs to the brain or spinal cord and from from the brain or spinal cord to the sense organs.
MORE ABOUT NERVOUS SYSTEM//
The human nervous system can send messages at the rate of 120 meters in one second, that is a message can travel from your bone to the tip of your feet, nearly 100 times in one second.
What is reflex action?
At times the body needs to respond quickly to avoid damage. At such times the body experiences a reflex action. An automatic movement I response to a stimulas is called a reflex action.
In most cases, the reflex action does not involve the brain.
What happens when your fingure gets picked by a pin?
The pricking of the pin is the stimulus which causes pain. You feel the pain and at once a message is send to the spinal cord. The spinal cord acts immediately by sending a message to the arm muscle. The body responds quickly by moving away the arm. this is known as reflex action.
How does the sense organ works?
EYES: Each Eyes have a lens. When you look at an object, light passes through the lens and forms an image inside the eye. this image is converted into a message. the nerves which connect the eye to the brain carry the message to the brain. the brain recognizes the message and helps you to see things.
EARS: The ear can be divided into external ear, middle ear and internal ear. The middle ear is a narrow canal. At the end of the canal is the eardrum, which is a very thin membrane, when sound enters the middle ear, it vibrates the eardrum. The vibrations are converted into the messages. The nerves present in the inner ear pick up these messages and carry them to the brain, The brain then helps you to recognize sound.
NOSE: When the nose senses the smell, it is covered into a message. The message is picked up by the nerves inside the nose and is carried to the brain. The brain then helps us to know the smell.
TONGUE: The tongue has taste buds, which can sense sweet, sour, salty and bitter tastes. The taste buds are connected to nerves. When we place food in the mouth, the tongue senses the taste and convert it into a definite message. The nerves connected to the taste buds pick up the message and carry it to the brain. The brain recognizes the message and helps us to know the taste of things we eat.
SKIN: Your skin is also a sense organ. Your able to sense pain and temperature, and feel things with the help of the skin. It is richly supplied with nerves. Messages are conveyed by these nerves mostly to the spinal cord.