Difference between parasympathetic and sympathetic nervous system

Sympathetic vs Parasympathetic Nervous Systems(Similarities and Differences between Sympathetic and Parasympathetic Nervous Systems)

The involuntary or reflex functions in the body are controlled by a part of peripheral nervous system called Autonomous Nervous System (ANS). ANS regulate the functions of internal organs (visceral functions) particularly the functions of heart, stomach and intestine. The Autonomic Nervous System composed of two components:

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Sympathetic vs Parasympathetic Nervous Systems(Similarities and Differences between Sympathetic and Parasympathetic Nervous Systems)
Similarities between Sympathetic and Parasympathetic Nervous System
Difference between Sympathetic and Parasympathetic Nervous System

Sympathetic Nervous System (SNS): They are the part of ANS which originate from the spinal cord of the thoracic and lumbar region. They control the ‘fight-or-flight’ response or the ‘sympatho-adrenal response’ in the body. SNS prime the body for acting in threatening situations for survival. The sympathetic nervous system acts in the body as complementary to the action of Parasympathetic Nervous System.

Parasympathetic Nervous System (PNS or PSNS): Part of ANS originates from the spinal cord and medulla which control the ‘rest-and-digest’ or ‘feed-and-breed’ activities in the body. They act in the body as complementary to the action of SNS.

The present post describes the similarities and differences between Sympathetic Nervous System and Parasympathetic Nervous System

Similarities between Sympathetic and Parasympathetic Nervous System

Ø Both are the part of ANS.

Ø Both originate from the spinal cord.

Ø Both have huge influence on physiological process of the body such as respiration, circulation, digestion, urination and reproduction.

Ø Both have role in maintaining the homoeostasis of the body.

Ø Both composed of pre-ganglionic and post-ganglionic neurons.

Difference between Sympathetic and Parasympathetic Nervous System

	Sympathetic Nervous System (SNS)	Parasympathetic Nervous System (PNS)
Origin	Originated from the cranial, thoracic and lumbar region of the central nervous system	Originated from the cranial and sacral region of the central nervous system
Main activity in the body	Prepare the body for intense physical activity	Relax the body and inhibit high energy functions
Position of ganglion	Close to the spinal cord, away from the effector	Away from spinal cord, close to effector
Size of pre-ganglionic fibres	Short	Long
Size of post-ganglionic fibres	Long	Short
Number of post ganglionic fibres	Large numbers	Very few numbers
Coverage area of pre-ganglionic fibres	Covers a wide are	Covers only a restricted area
Mode of effect	Show diffused effects in the area of influence	Shows localized effects in the area of influence
Transmitter substance	Noradrenaline released at the effector	Acetylcholine released at the effector
Time of dormancy	Dormant during danger	Dormant during rest
Control	Control reactions to stress	Control routine body activates
Homoeostatic effect	Excitatory homoeostatic effect	Inhibitory homeostatic effect
Effect on blood level	Increase	Decrease
Effect on metabolic rate	Increase	Decrease
Effect on heart beat	Increase	Decease
Effect on sensory awareness	Raise sensory awareness	Restore sensory awareness to normal level
Effect of pupil	Dilate pupils	Constrict pupils
Effect on saliva secretion	Inhibit saliva secretin	Stimulate saliva secretion
Effect on pulmonary system	Dilates bronchial tubules	Constrict bronchial tubes
Adrenaline release	Release adrenaline from adrenal gland	Nor action of adrenal gland
Effect on the conversion of glycogen to glucose	Increase the rate of glycogen to glucose for muscle power	Nor action in the conversion
Effect on urinary output	Decrease urinary output	Increase urinary output
Effect on rectum	Rectum is contracted	Rectum is relaxed