Emerald Robinson: Hi! I am Emerald Robinson and in this What is? video we will examine the human bodys master organ system, the nervous system. The nervous system is the body system that controls and regulates everything that we do, both voluntary actions like moving muscles and involuntary actions like breathing.
There are two main parts of the nervous system. The central nervous system composed of the brain and spinal cord and the peripheral nervous system formed mostly of nerves fibrous bundles that transmit electrical signals throughout the body, both parts are made primarily of special cells called neurons.
The central nervous systems job is to process signals that come from the bodys nerves. These signals start in the limbs and organ systems and pass through the spinal cord on their way to the brain.
Although the brain is extremely complex, we can think of it as having three large regions. These are the forebrain, responsible for thinking and creating language. The midbrain which processes sensory information from our eyes and ears and the hindbrain which tells us maintain balance and coordinate our muscles. The hindbrain also controls most of our involuntary actions.
The peripheral nervous systems job is to connect limbs and organs to the central nervous system; it does this through two types of neurons. Sensory neurons carry electrical impulses created by our senses to the central nervous system. Motor neurons transmit them from the central nervous system to muscles and glands.
Although these parts may seem very different, the neurons that make them are very similar. The neurons receive electrical signals from neighbor cells through branch like extensions called dendroids. The signals pass through the cell body, then leave through the axon, a long extension that leads to the next nerve cell, all of these happens very quickly, our nervous system sends signals that speeds up to 200 miles per hour.