The Nervous System

    The Nervous system, as we all know, is basically the master controller of the body. It sends messages to every part of the body, telling the different areas what to do, and how to react. One major part of the Nervous system is the spinal cord. The spinal cord can move a lot of data very quickly. Its job is to carry messages to and from the body to the brain. There are 32 different nerves that connect directly into the spinal cord. Reflexes are processed straight into the spinal cord as well.
   
    Neurons send signals to the other cells as electro-chemical waves. These waves travel along thin fibers called axons which cause chemicals called neuro-transmitters to be released at junctions called synapses. Some axons are wrapped in a myelin sheath.

     Some more important parts of the Nervous system are the cerebrum, cerebellum, and brain stem. The cerebrum is the largest portion of the brain responsible for all the voluntary processes that occur every day. The cerebrum is broken into 2 parts: left & right. The left side of the cerebrum is responsible for problem solving and analytical thought, while the right side is responsible for creative thought. The cerebellum is there to aid the cerebrum in the task of moving muscles, and it also helps in maintaining balance in the body. The last part we are going to talk about is the brain stem. The brain stem sits at the base of the brain and connects it to the spinal cord, and it also controls flow into the brain and body.

   The Somatic Nervous system controls functions that are under conscious voluntary control such as skeletal muscles and sensory neurons of the skin. The Autonomic Nervous system, mostly motor nerves, controls functions of the involuntary smooth muscles, cardiac muscles, and glands. The Autonomic Nervous system provides almost every organ with a double set of nerves. The 3 types of neurons are arranged in circuits and networks, the simplest of which is the reflex arc. In a simple reflex arc, such as the knee jerk, a stimulus is detected by a receptor cell. A sensory neuron carries the impulse from the site of the stimulus to the central nervous system (the brain or spinal cord) where it synapses with an inter-neuron. The inter-neuron synapses with a motor neuron, which carries the nerve impulse to an effector, such as a muscle, which responds by contracting.