The cells, whose role is to keep us informed about the outside world, are called nervous cells.
In less developed living beings nerve cells are found in the skin and directly transmit messages to the deeper parts of the body. In humans and animals, most nerve cells are in the body, although they receive messages from the skin.
The task of nerve cells is to convey the message through the body, each message into the appropriate place. The vibrant fibers along which these messages travel are like “cables” (conductors) and called nerves.
Did you know… Sneezing starts in the nerves …
Four main types of nerve cells
There are four main types of cells whose fibers build nerves. These are independent groups in the body, so they have a special role.
The first type receives messages from the outside world, such as warm, cold, pain, touch, light, taste, and so on, and performs them in the brain. They are called sensory or sensory nerves.
The third type of cells performs a connection job: transmits messages to larger distances in the body and connects motor nerves and sensory.
The fourth type of nerve cell has the task of message or stimulus from the outside world, such as cold, warm or pain, transferred to the brain, to be recognized as feeling of cold, hot or pain.
Did you know… Drugs are stimulants that affect the brain and the central nervous system.
Nervous system parts and functions
The human nervous system is like a wire mesh that starts from the brain and connects all parts of the body. The brain is the center of this system. Out of brain commands go through the nerves and urge us to move, laugh, eat and, in any case, to behave as human beings.
Nerves serve the brain as a connection system. Through a special part of the nervous system, the brain receives information about everything that is happening in the body. The main line connecting the brain with the body is the spinal cord. It’s located in the spinal canal. The spinal cord is actually a group of nerve bundles, similar to the set of wires that make up the “cable”.
Each nerve has two roots that connect it to the spinal cord: the back and front root. Back roots transmit messages to spinal cord, and than from spinal cord to the brain. Front roots transmit brain messages to various parts of the body.
But, as you know, the body also performs unwilling actions. All organs have certain and important tasks that are performed without our conscious thinking. For example, digestion and breathing are performed automatically and independently. Heart work is also automatic.
These unwilling actions, and many others, automatically control the other nervous system called the autonomic nervous system. It does not require conscious control. It builds a separate nerve network in the body. To live and work as human beings, we need both systems.
How fast does information travel through the nervous system?
The nervous impulse, stimulus that travels along a nerve, moving at a speed of only 250 kilometers per hour! This means that a message can be sent more quickly outside our body than from one part of the body to another. Television, radio, and phone carry messages much faster than nerves.