The sympathetic division is the other main division of the autonomic nervous system, along with the parasympathetic division. It is responsible for activating the body’s “fight or flight” response, preparing the body for intense physical activity, stress, or perceived threats.

When the sympathetic division is activated, it triggers a series of physiological changes that prepare the body to deal with a perceived danger or stressful situation. Some key features of the sympathetic division include:

1. Increased Heart Rate: The sympathetic nervous system stimulates the heart to beat faster, increasing blood flow and oxygen delivery to the muscles and vital organs.
2. Dilated Pupils: Activation of the sympathetic system causes the pupils to dilate, allowing more light to enter the eyes and enhancing visual acuity.
3. Bronchodilation: The sympathetic division relaxes the smooth muscles of the bronchioles in the lungs, expanding the airways and increasing oxygen intake.
4. Mobilization of Energy: The sympathetic response triggers the release of stored energy in the form of glucose from the liver and fatty acids from fat cells. This provides the body with a quick source of fuel for physical exertion.
5. Inhibition of Digestion: The sympathetic division inhibits digestive processes by reducing blood flow to the digestive organs and decreasing secretion of digestive enzymes. This redirection of resources allows energy to be prioritized for other functions.
6. Increased Blood Pressure: The sympathetic nervous system constricts blood vessels, which raises blood pressure by increasing resistance to blood flow. This ensures that oxygen and nutrients are delivered to the muscles and vital organs during stress or physical activity.
7. Sweating: Activation of the sympathetic system leads to increased sweating, helping to cool the body during heightened physical activity or stress.
8. Suppression of Nonessential Functions: The sympathetic response suppresses nonessential functions such as salivation, tear production, and urination to conserve energy and redirect resources to more critical areas.

The sympathetic division prepares the body for action and is crucial for survival in threatening or demanding situations. It activates various physiological changes that optimize physical performance and increase the body’s readiness to respond to stress or danger.

 © Linda C J Turner