Difference Between Sympathetic And Parasympathetic Nervous System: Overview, Function

Introduction Of The Autonomic Nervous System (Ans)

It is the part of the peripheral nervous system controlling the involuntary activities of the body: heart rate, digestion rate, respiratory rate, and pupillary response. It works at a subconscious level and has as its chief divisions the sympathetic and parasympathetic nervous systems, which have opposing roles in maintaining homeostasis within the body.

The sympathetic and parasympathetic systems have to be understood for maintaining the major activities within the body that help keep the person alive and comfortable. The sympathetic system gets the human body ready for stressful situations, while the parasympathetic system gets it ready for rest and recovery.

Sympathetic Nervous System (SNS)

• Prepares the body for 'fight or flight.'

• Increases vigilance and energy expenditure

• Mobilises the body's resources during stress

Structure Of The SNS

• Arises from the thoracic and lumbar region of the spinal cord.

• Composed of ganglia and neural paths extending to target organs.

Functions Of SNS

• Fight or flight response

• Increased heart rate

• Dilated pupils

• Expanded airways

• Inhibited digestion

• Release of glucose from the liver for energy

Parasympathetic Nervous System (PNS)

• The PNS does 'rest and digest' activities

• It conserves energy and resources

• Facilitates restoration and upkeep functions.

Structure Of The PNS

• Originate from the cranial and sacral regions of the spinal cord

• Has long preganglionic and short postganglionic fibers

• Ganglia are located near or inside target organs

Functions Of The PNS

• Rest and digest the response

• Decreased heart rate

• Small pupils

• Tightened airways

• Stimulated digestion and glandular activity.

• Promotes nutrient absorption and energy storage.

Table: Comparison Between Sympathetic And Parasympathetic Nervous Systems

Interactions Between The Sympathetic And Parasympathetic Nervous Systems

• Both systems work together to maintain body homeostasis

• Dual innervation: Most organs receive input from both systems

• Fine-tuned regulation depending on the body's needs

• Heart: SNS increases heart rate, PNS decreases it

• Digestive system: SNS inhibits digestion, and PNS stimulates it

• Make sure the body acts appropriately based on the situation

• Needed for adaptation to, as well as recovery from stress.

Common Disorders Related To SNS and PNS

• Hypertension: Overactive SNS,

• Heart: SNS increases heart rate, and PNS decreases it.

• Digestive system: SNS inhibits digestion, and PNS stimulates it.

Treatment And Management

• ANS-directed medications (e.g., beta-blockers)

• Lifestyle modifications and stress management techniques to balance SNS and PNS activities.

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