THE NERVOUS SYSTEM

The nervous system has two distinct parts. The central nervous system comprises the brain and spinal cord. The peripheral nervous system is the network of nerves that connects the brain and spinal cord to the rest of the body.

The organs of our body, such as the heart, stomach and intestines, are regulated by a part of the nervous system called the autonomic nervous system.
The autonomic nervous system is part of the peripheral nervous system and it controls many organs and muscles within the body.

The autonomic is divided in the sympathetic and the parasympathetic divisions.
Most organs receive impulses from both divisions and under normal circumstances they work together for proper organ function and adaptation to the demands of life.
The sympathetic system tends to stimulate a particular function while the parasympathetic tends to calm.

Normally there is a balance kept between the sympathetic and parasympathetic nervous systems, but in long term chronic stress This balance can be disturbed and either one of the sympathetic or parasympathetic nervous systems can predominate over the other leading to stress related health problems.

If the body is stressed, such as in the "fight or flight" response, the sympathetic nervous system dominates.

When the sympathetic system is activated the parasympathetic system is inhibited - thus the brain's primary mechanism for producing calm and relaxation is shut down and the body and mind are forced to remain vigilant in the face of danger.

Long time over-stimulation of the sympathetic nervous system can lead to problems as anxiety, hypertension, and digestive disturbances.

The inner region of the adrenal glands is part of the sympathetic nervous system and the body's first line of defense and response to physical and emotional stress. These are secreted by the adrenal glands. The hormones involved in the stress response include adrenaline, noradrenaline, and cortisol.
Adrenal glands release adrenaline and noradrenaline.
Adrenaline prompts an increase in the hormone glucagon, which is responsible for mobilizing glucose normally stored in our muscle and liver as glycogen. This results in a sudden increase in energy for immediate action.
Energy which is not utilized in sedentary situations, contributes to unhealthy fluctuations of blood sugar levels, which has consequences for cardiovascular disease, diabetes, anxiety and insomnia.

Cortisol is also released from the adrenal glands. Raised cortisol levels are associated with a suppressed immune system, heart disease and cancer.
Excess cortisol in the blood interferes with mood enhancing neurotransmitters called serotonin. Disturbances in serotonin levels can be a factor in causing clinical depression and anxiety disorders as well as being linked to insomnia, obesity and increased sensitivity to pain.

Other consequences of to much sympathetic activity is:

1. The digestive system slows.


2. The pituitary gland and brain secrete endorphins to reduce pain.


3. Depleted energy levels when stress is constant.


4. Dry mouth.


5. Muscles are activated in response to stress as part of the fight-flight pattern. When muscles are active they use much more energy than when relaxed.