The basic unit of the nervous system is the neuron. There are three parts to the neuron, they are the cell body, the dendrites, and an axon. The dendrites of the neuron are branch link extension of the neuron that gets the impulse and carry them toward the cell body. The axon is a single extension of the neuron that carries impulses away form a cell body and toward the neurons, muscles, or gland. A white material covers the axon called myelin sheath, so it insulates the axon.
There are three different kinds of neurons, sensory neurons, that carry impulse from the body to the spinal cord and brain. The next neuron is the interneuron, they are the spinal cord and brain, and they process incoming impulse and pass responses onto the motor neurons. The final neuron is the motor neuron, they carry the responding impulse away from the brain and spinal cord to amuse or gland.
When a neuron is not transmitting an impulse, the neuron is said to be at rest. A neuron has an active transport system called a sodium/potassium pump. It increases the concentration of positive charges on the inside of the membrane and negative charge in the outside of the neuron. When a neuron is a rest, it is said to be polarized, polarized means that a membrane that has the ability to transmit an impulse. An impulse is transmitted when a sodium channel opens up and sodium ions rush into the cell. The inside of the cell becomes more positively charged than the outside, this is called depolarization. When the impulse passes the gated channels move back to resting state.
Neurons do not touch, but they still transmit impulses. This is possible with the space between it called a synapse. There is a chemical called a neurotransmitter, which goes across the space to the dendrites of the next neuron. The neurotransmitters enter the next neuron through an open ion channel.
The brain and spinal cord together make up the central nervous system, which coordinates all your body’s activates. Another part of your nervous system is called the peripheral nervous system it is made up of all the nerves that carry messages to and from the central nervous system.
There are three major parts to the brain. One of them is the cerebrum, which is your conscious activities, intelligence, memory, and more. Another part is the cerebellum, which controls your balance, posture, and coordination. The final part of the brain is the medulla oblongata, which controls involuntary actions.
There are two parts to the peripheral nervous system, one is the somatic nervous system which controls moves you can make on your own like moving your arm, and another part of it is reflexes. The second part of this second is the autonomic nervous system, which controls the involuntary or not under conscious control. This part of the nervous system is also divided into two parts. One is the sympathetic nervous system, which is used in a time of stress, and the other is the parasympathetic nervous system when it controls your body during times that you are at rest.
