Table of Contents
- Classification of Nervous System
- What Is a Sympathetic Nervous System?
- Sympathetic Nervous System – Components
- Sympathetic Nervous System – Functions
- Frequently Asked Questions
Classification of Nervous System
The nervous system regulates all bodily functions. The nervous system is mostly split into two sections:
- CNS – Central nervous system
- PNS – Peripheral nervous system
The spinal column and the brain are the components of the central nervous system, whereas PNS is made up of spinal nerves that originate from the spinal cord and cranial nerves that come from the brain. PNS is split into two – autonomic and somatic nervous systems.
The autonomic nervous system is responsible for controlling vegetative or visceral functions.
Therefore, it is also known as the vegetative or involuntary nervous system. Sympathetic division and parasympathetic division are the two divisions of the autonomic nervous system.
What Is a Sympathetic Nervous System?
Sympathetic nervous system is the main component of the ANS or autonomic nervous system. The major function of the sympathetic nervous system is to activate the body’s flight or fight response. This nervous system becomes more active when in danger, stressed or when engaged in physical exercise. Sympathetic activities include accelerating heart rate, respiration, enhancing vision and slowing down bodily functions including digestion. However, it is continuously in an active state in order to maintain homeostasis.
The parasympathetic nervous system, which drives the body to breed, feed, digest and rest is said to be antagonistic to the sympathetic nervous system.
Sympathetic Nervous System – Components
Sympathetic nervous system shares many of its components with other areas of the nervous system. A neuron is the most common sort of cell in any nervous system. It can send and receive messages. The spinal cord is where the majority of the impulses sent by the sympathetic nervous system originate. The signals travel from the spinal cord and activate the ganglia. The sympathetic chain of ganglia on either side of the spinal cord makes up the sympathetic system. The required signals are broadcast widely throughout the body by the sympathetic ganglia to various body parts. This may include the arteries, digestive system, sweat glands, heart and lungs.
Preganglionic or presynaptic neurons are the sympathetic neurons whose cell bodies are in the thoracic and lumbar portions of the spinal cord. Chemical synapses are the means through which these neurons communicate with the postganglionic or postsynaptic neurons of the peripheral nervous system. Noradrenaline serves as a postganglionic neurotransmitter in the majority of synaptic neurons.
Explore:Peripheral Nervous System
Sympathetic Nervous System – Functions
Within the human body, the sympathetic system has a very wide range of functions. All of the blood arteries, arrector pili, sweat glands and viscera are innervated by sympathetic fibres, which are a part of almost all spinal nerves and periarterial plexuses. Only avascular structures, such as nails and cartilage, are excluded from the sympathetic system’s range of motion.
- The sympathetic and parasympathetic divisions of the nervous system collaborate closely to produce effects that are opposite but closely synchronised.
- The sympathetic nervous system is engaged in energy expenditure (catabolism), allowing the body to make the proper use of energy in reaction to emergencies and stressful situations, such as the flight or fight response.
- Pupil dilating, piloerection, sweating, constriction of cutaneous blood vessels, adrenaline release, increased heart contraction, bronchodilation and decreased digestion are all symptoms of sympathetic system activation.
- Blood vessels are tonically kept in a resting state of moderate vasoconstriction under typical circumstances. Vasoconstriction rises as sympathetic impulses rise and vice versa.
- However, sympathetic activation causes vasodilation in coronary arteries, skeletal muscles and external genital veins.
Keep exploring BYJU’S Biology to learn more such exciting topics.
See more:
- Central Nervous System
- Difference between Nervous System and Endocrine System
- Difference between Sympathetic and Parasympathetic Nervous System
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