They usually end at nerve endings in places like the tips of your fingers and toes, or just underneath the surface of your skin. Others are motor, and they also conduct information one way: From your brain to your muscles.īoth your spinal and cranial nerves continue to branch outward as smaller nerves throughout your body. They conduct information one way: Up to your brain. Some of the nerves in this system are sensory. The spinal nerves branch out further and become the nerves that spread out through your body. Cranial nerve (CN) II, which connects to your eyes, is technically part of your brain, not your somatic nervous system.įarther down, your somatic nervous system has connections in all 31 spinal nerves. These are 12 pairs of nerves (which use Roman numerals to set them apart), 11 of which have connections that are part of your somatic nervous system.

In your head and neck, it does that through your cranial nerves. Your somatic nervous system spreads outward from your brain and spinal cord. But you can also breathe manually, deliberately controlling when you inhale and exhale. Under most circumstances, you breathe automatically and without thinking about it. One of the expert theories about why that happens has to do with your nervous system’s layout.Īnother example of how your somatic nervous system can affect internal organs is controlling your breathing. One of the best-known examples of this is pain from a heart attack that you feel in your left arm, back, jaw or abdomen. How does the somatic nervous system help with other organs?įor most of your internal organs, your somatic nervous system only helps indicate organ pain using “referred pain.” This is when you feel pain in a specific area, but the pain is actually coming from a problem nearby. The signals from your brain must pass through your somatic nervous system to reach those muscles and make them move. Your body’s muscles rely on signals that give them instructions to help you move around. Your sense of touch below your neck uses your somatic nervous system to reach your spinal cord, which then relays signals to your brain. The other senses on your head - sound, smell, taste and touch - all use your somatic nervous system to reach your brain. All but one of your senses travel through your somatic nervous system to reach your brain (sight is the exception because your retina and optic nerve connect directly to your brain). Your somatic nervous system has two main jobs:

Somatic nervous system diagram