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The nervous system is a very important system in your body. The nervous system controls almost everything you do.
The nervous system has two basic functions.
The nervous system has two parts:
The CNS consists of the brain and the spinal cord.
The PNS is all of the parts of the nervous system except for the brain and the spinal cord. The PNS connects all parts of the body to the CNS. The PNS also uses structures called nerves to carry information between the central nervous system and the rest of the body. (Image of Nervous System)
A very important part of the peripheral nervous system are neurons. A neuron is a type of nerve cell that is specialized to receive and transfer electrical energy messages called impulses. A neuron's structure starts with a cell body. The cell body has a nucleus and other cell organelles. Neurons also have other special structures called dendrites and axons. Dendrites are short extensions of the cell that receive information from other cells and their dendrites. Axons are short or long extensions that carry away information. The end of an axon has branches that allow information to pass to other cells. Each end
of the branch is called an axon terminal. (Image of Neurons)
Another type of neurons are sensory neurons. Sensory neurons gather information about what is happening inside and outside the body. The end of sensory neurons are called receptors. Receptors detect changes inside and outside the body. The other type of neurons are motor neurons. These types of neurons send impulses from the brain and spinal cord
to other systems throughout the body. (Image of Neuron)
In the peripheral nervous system, there are two other kinds of nerves. The first type of nerves are the somatic nerves. These are part of the somatic nervous system. These are neurons that are under your conscious control. These neurons control voluntary movements such as writing, talking, or smiling. Voluntary movements are movements that you can control. The next type of nerves are the autonomic nerves and they are a part of the autonomic nervous system. The autonomic nerves are neurons that you don't have to use your conscious control for. They control involuntary movements such as digestion and heart rate. You cannot control involuntary processes. The autonomic nervous system has the main job of keeping all the body's functions in balance. It has two divisions that work together to keep your body in balance. These two divisions are called the sympathetic nervous system and the parasympathetic nervous system. These two systems work together to keep your body stable and of this process is called homeostasis. (Image of Neurons)
The central nervous system also has some very important parts to it. The control center of nervous system is called the brain. The brain is a mass of nerve tissue. The brain controls both involuntary and voluntary processes. The brain has three parts: the cerebrum, cerebellum, and the medulla. The cerebrum is the largest part of the brain. It is where thinking occurs and memories are stored. It controls voluntary movements and allows you to sense touch, light, sound,
odors, taste, pain, heat, and cold. The cerebrum also has two halves called hemispheres. The left hemisphere directs the right side of the body, and the right hemisphere directs the left side of the body. The second largest part of the brain is the cerebellum. The second-largest part of your brain is the cerebellum. It lies beneath the back of the brain. The cerebellum processes sensory information from your body. This allows the brain to keep track of the body's position. The smallest part of the brain is the medulla. You couldn't live without it because it controls involuntary processes such as heart rate or involuntary breathing. (Image of Brain and Spinal Cord)
The other part of the central nervous system is the spinal cord. The spinal cord is made of neurons and axons that pass impulses to and from the brain. The spinal cord is surrounded by protective bones called
vertebrae. (Image of Spinal Cord)