Describe the origin and structure of sympathetic and parasympathetic nerves and state three functions of each nerve.
The autonomic system is made up of two divisions, the sympathetic and parasympathetic systems. They usually work antagonistically in the organs, but in a well integrated manner. It is the balance of the actions of both divisions that maintains a stable internal environment in the body.
While the sympathetic system is also important at rest, it is essential for preparing us for emergencies, in other words, for “fight-or-flight” responses. If you have ever been scared or anxious, attacked or threatened, you have basically experienced activation of your sympathetic system. To prepare yourself for an emergency in a “fight-or-flight” response, the sympathetic system activates numerous complex pathways and components to achieve faster breathing, increased heart rate and blood pressure, dilation of pupils, changes in blood flow, so blood leaves the skin, stomach and intestines and goes to the brain, heart and muscles where it’s needed, increased sweating and “goose-bumps” as the hair on your skin stands on end; all those things you feel during a fight-or-flight response.