Our Nerve Systems

Sympathetic and Parasympathetic Nerve Systems


The sympathetic and parasympathetic nerve system control muscles and glands and also monitor visceral organs. The two systems balance the stimulation of organs by stimulating or inhibiting the function of an organ.

The parasympathetic nervous system is active during periods of digestion and rest. It stimulates

  1. The production of digestive enzymes,

  2. The processes of digestion, urination, and defecation,

  3. Reduction of blood pressure and heart and respiratory rates and

  4. Conservation of energy through relaxation and rest.

The sympathetic nervous system prepares the body for a “fight‐or‐flight” situation resulting in

  1. The heart rate increasing for more oxygen intake.

  2. The blood vessels dilating to increase blood supply.

  3. The adrenal medulla releasing adrenalin and norepinephrine to increase the metabolic rate of cells.

  4. The liver releasing glucose into the blood for more fuel and energy production in the cells.

Most of us go from the "fight or flight" into "Freeze and Fear" condition.  In these situations, the conscious movement of Conscious Mindful Breathing, activating the diaphragm, will greatly balance the sympathetic and parasympathetic nerve systems.

Vagus Nerve System Balances Other Nerve Systems

The vagus nerve system forms part of the involuntary nervous system and commands unconscious body procedures, such as keeping the heart rate constant and controlling food digestion.  This stimulation causes a drop in blood pressure and heart rate.

Parasympathetic innervation of the heart is partially controlled by the vagus nerve.

Phrenic Nerve System

The phrenic nerves originates in the neck (C3-C5) and pass down between the lung and heart to reach the diaphragm. There are two phrenic nerves, a left and a right one.  They  passes motor information to the diaphragm critical for breathing.  Equally important, the diaphragm also sends sensory information to the vagus,  sympathetic and parasympathetic nervous systems

The phrenic nerve receives innervation from parts of both the cervical plexus and the brachial plexus of nerves.

The phrenic nerves contain motor, sensory, and sympathetic nerve fibers.  The diaphragm receives its sole neurological impulse from the phrenic nerves. 


The phrenic nervous system also modulates the "fight or flight" response of the sympathetic nervous system.  By performing Conscious Mindful Breathing, the phrenic nerves are stimulated. This transmits signals to the Vagus nerves which then calms the sympathetic nervous system.  Thereby we are better able to control anxiety and stress inducing conditions that we all continually experience daily.