Parasympathetic nervous system

The Parasympathetic nervous system maintains normal functioning of the body in non threatening situations.  It helps keep the body in a relaxed unstressed condition.  If we stimulate the parasympathetic nerves it can:

• Reduce the heart rate – because we don’t need the oxygen, we are ‘at rest’

• Cause us to have an erection – the smooth muscles relax [limp willies are caused by contraction not relaxation]

• Stimulate the pancreas, stomach and intestines to work – again the smooth muscle are relaxed and get to work

• Constrict our pupils

• Constrict the bronchioles  - because more oxygen is not needed, the lung capacity does not need to be so large

• Stimulate urination – we don’t need all the water we have retained in order to sweat and breathe heavily for the  ‘flight’ response, so we get rid of it by weeing

• Dilates the blood vessels to the gut to help in digestion of any food we might eat to build up our reserves of energy

• Stimulate saliva production

These nerves have ‘cholinergic’ nerve endings and use acetycholine as the neurotransmitter.

Observations

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• Clinical Results and Physiological Effects of Immobilizing Lung Chamber Therapy in Chronic Pulmonary Tuberculosis
• Dr Duke's list of plants containing acetylcholine
• Effect of short-term practice of breathing exercises on autonomic functions in normal human volunteers
• Effect of slowed respiration on cardiac parasympathetic response to threat
• Effect of yogic bellows on cardiovascular autonomic reactivity
• Immediate effect of slow pace bhastrika pranayama on blood pressure and heart rate
• Use of Controlled Diaphragmatic Breathing for the Management of Motion Sickness
• Watson, Lyall - Cold fronts and warm fronts