The spinal cord is responsible for carrying three types of signals from your body to your brain and from your brain to your body. These signals are sensory, signals that evoke feeling, motor, signals that evoke movement, and reflex. Each of these signals is carried out in very different ways.
Sensory signals are used to evoke feelings within the body. These include feelings of hot and cold, pain, touch, and pressure. These signals are sent along the pathways of nerves in the body to the spinal cord and then to the brain. Once these signals, or signal, reach the brain, you are able to feel something. This process happens so quickly that we do not even realize it’s happening. In addition to evoking feelings, sensory signals give you an idea of your body’s position. This means knowing whether you are sitting or standing, and recognizing where your body parts are in relation to the rest of the body.
For example, a sensory signal allows you to be aware that your arm is reaching out and feeling that the puppy you are petting is soft.
Have you ever experienced a spasm? This was the result of a reflex signal. Reflex signals are muscle movements that are triggered by a signal that does not come from your brain. To get a response, some signals only need to reach the spinal cord. Once the signal makes it to the spinal cord, it loops through the spinal cord and goes straight back to the body part it came from – this causes a reaction in the form of a spasm. Because reflex signals are meant to be used to protect your body, they happen more quickly than other signals and do not need to reach the brain for a reaction.
So how is this signal initiated? Stretching of or pushing on the nerves in your muscle trigger the nerves to send a signal to the spinal cord. However, when the signal reaches the spinal cord, it loops through at the level it comes in, leaving the spinal cord and going back to the muscle. Once it returns to its starting point, it causes the muscle to squeeze and contract.
Motor signals are signals that tell your muscles to move. These signals not only send the command for the muscles to move, but also how and when to move. Unlike sensory signals, motor signals begin in the brain and travel through the spinal cord, out the spinal nerves and to the rest of the body. These signals are sent and received so quickly that we do not think about or realize they are happening.
As an example, motor signals allow you to hug someone.
Source: myshepherdconnection.org, Accessed: 4/7/17