Sensory and motor neurons have different jobs. Motor neurons transport information from the central nervous system to the body's muscles and glands, while sensory neurons relay signals from body parts to the central nervous system.
The Cell Body
Each neuron has a cell body. The cell body, also known as the soma, is the part of the neuron the houses the cell's nucleus. It is spherical in shape and connects to the cell's dendrites; cell dendrites bring information to the neuron of other cells. Axons also connect to the cell body. The axons transfer information to other cell neurons. An axon that ends in a terminal that contains a chemical is known as a neurotransmitter. If axons and dendrites from different cells bunch together, this creates nerves. Groups of multiple cell bodies form ganglia.
Others parts found in the cell body include the cell's organelles. The organelles perform basic cell functions, such as synthesizing proteins, transporting materials and creating energy. Each organelle has its own job. For example, the cell nucleus houses cell DNA and regulates all of the other processes that occur within the cell. The cell's ribosomes are the cell's organelles that handle the production of proteins.
How Neurons Function
Neurons are specialized cells that transmit messages throughout the body. Without neurons, the body would not have the ability to respond to stimuli. The body's neurons use weak electrical currents to transfer messages throughout the body. Processes conducted by nerve cells happen incredibly fast, in thousandths of a second. That allows the human body to react quickly to stimuli in the environment. A hand touching a hot stove is removed almost immediately so that serious injury does not occur.
When the axon sends a message, the message travels to the end of the axon. An axon has a tail-like shape that makes message transportation possible. At the end of the axon, the axon converts this electrical message into a chemical message by releasing neurotransmitters. Neurotransmitters then travel through a synapse (a short space between an axon and a dendrite). Once the dendrite receives the neurotransmitter, it converts this chemical signal back into an electrical signal. This newly converted electrical signal then travels through the neuron to other nearby neurons to elicit the appropriate reaction.
Sensory Versus Motor Neurons
The messages sent by sensory neurons permit the body to detect external sources of stimuli, such as light, taste, heat, odor and sound. These neurons allow the body to react involuntarily. For example, when bright sunlight hits your eyes, sensory neurons send a message that causes you to automatically squint so that the light does not damage your eyes. If the body did not complete this action voluntarily, the time it takes to decide to close your eyes and relay that message may cause the light to damage your eyes.
When your body needs to make a deliberate movement, motor neurons make this possible. Assume that you are playing a game of soccer. You need to lift your leg and extend your foot in order to kick the ball. Motor neurons transfer the messages required to complete these movements from the brain to the necessary body parts.