The Sympathetic Nervous System and its Functions

The sympathetic nervous system is a part of the autonomic nervous system that is responsible for the "fight or flight" response in the body. It prepares the body to respond to stress and danger by activating various physiological responses.

Increase in Blood Glucose Levels

One of the primary functions of the sympathetic nervous system is to increase blood glucose levels. When the body is under stress or danger, the sympathetic nervous system releases hormones such as epinephrine and norepinephrine, which stimulate the liver to release stored glucose into the bloodstream. This process is known as glycogenolysis and helps increase blood glucose levels, providing energy to the body to respond to the stress or danger.

Decrease in Blood Flow to the Intestines

Another function of the sympathetic nervous system is to decrease blood flow to the intestines. This response is necessary during a "fight or flight" situation as the body redirects blood flow to the muscles and organs that need it the most. By reducing blood flow to the intestines, the sympathetic nervous system ensures that the body has enough blood and oxygen to respond to the stressor.

Other Functions of the Sympathetic Nervous System

The sympathetic nervous system also has other functions that help prepare the body for a stress response, such as:

- Increasing heart rate and blood pressure
- Dilating the pupils to improve vision
- Increasing respiration rate to provide more oxygen to the body
- Constricting blood vessels in the skin to conserve heat
- Stimulating the adrenal glands to release hormones that help the body cope with stress

Conclusion

In summary, the sympathetic nervous system is responsible for increasing blood glucose levels, decreasing blood flow to the intestines, and activating various physiological responses that help the body respond to stress and danger.

Sympathetic neurons are frequently considered part of the peripheral nervous system (PNS), although there are many that lie within the central nervous system (CNS).

Sympathetic neurons of the spinal cord (which is part of the CNS) communicate with peripheral sympathetic neurons via a series of sympathetic ganglia.