Difference Between Sympathetic And Parasympathetic

Basically, our nervous system is the set of organs and structures formed through nervous tissues. Their main function is to receive and process information from the environment, in order to regulate the functioning of the other organs and systems of the same. The main difference between sympathetic and parasympathetic is that the sympathetic is responsible for regulating the body’s activation responses. On the other hand, parasympathetic is mainly for returning to a state of balance and conservation after the activation of the sympathetic system. The nervous system has two types:

  • CNC – central nervous system
  • PNS – peripheral nervous system

In the peripheral nervous system, it is the automatic or vegetative nervous system that regulates involuntary or unconscious functions like a bowel movement.

Automatic Nervous System Definition and Function

the Automatic Nervous System (also known as the vegetative nervous system) is situated on the periphery of the nervous system, despite being activated by areas such as the hypothalamus, most of its activity is centered in the spinal cord, the nerves peripherals, and brainstem. The nerves that leave the brain and go directly to all the organs of our body (efferent fibers) are part of the autonomic nervous system. The automatic nervous system is further divided into two parts:

  • Sympathetic Nervous System
  • Parasympathetic Nervous System

See Also: Nervous System Definition, Parts And Functions

Functions of ANS

It controls the muscles which surround the organs that regulate the excretory system (sweat, urine, and other secretions), and participate in the following processes:

  • Blood pressure
  • Digestion
  • Erection and ejaculation
  • Involuntary muscle contraction and relaxation
  • Control of reflexes and involuntary actions

The object of study of this article and their definitions will see below and then show their differences.

Difference Between Sympathetic And Parasympathetic in Tabular Form



The major function of the sympathetic is to mobilize the body’s response under stressful circumstances. The main function of the parasympathetic is to control all the involuntary acts and functions of the body.
It causes dilation of the pupils. It causes constriction of the pupils.
It increases the heart rate, therefore causing an increase in blood pressure. It slows down the heart rate, therefore causing a drop in blood pressure.
Involved in the fight or flight response. It maintains homeostasis and also, permits the rest and digest response.
Saliva secretion can be inhibited. Saliva secretion increases, digestion increases.
Sympathetic stimulates the adrenal glands and contracts the sphincters. Parasympathetic increases oxygen circulation to non-vital organs and relaxes the sphincter.

Sympathetic Nervous System

The sympathetic nervous system runs from the beginning of the spinal vertebrae in the first thoracic segment of the spinal cord that extends upward to the second or third lumbar segment. The major function of the sympathetic nervous system is to mobilize the body’s response under stressful circumstances. Sympathetic is the system that mediates the hormonal stress response. In the sympathetic system, the fight of the body’s responses to hormonal stress circumstances begins. It can be mentioned that the preganglionic fibers are short, leave the spinal cord, and travel within the nerves. Ganglion cells are located in the paravertebral sympathetic trunks or prevertebral ganglia, and their postganglionic neuron releases epinephrine or norepinephrine.

Sympathetic prepares the body for intense physical activity in emergencies. there are several minor functions of the sympathetic system are to dilate the pupils, increase the force and frequency of the heartbeat, dilate the trachea and bronchi, stimulate the adrenal glands, and contract the sphincters.

Important Sympathetic Nervous System Functions

  • Speeds up the heart rate
  • Maintains muscle tone
  • Stimulates orgasm
  • Opens the airways to increase oxygen in the blood
  • Inhibits the digestive system

Parasympathetic Nervous system

It is responsible for the regulation of internal organs of the rest of digestion and the activities which occur if the body is at rest such as sleep. As it is a resting system, the parasympathetic gives priority to the activation of the peristaltic and secretory functions of the digestive and urinary system, at the same time which it promotes the relaxation of sphincters for the evacuation of excreta and urine. It is also responsible for returning all previously activated organs to our natural state. For this, it transmits signals to the brain so that it releases acetylcholine and reaches the neurons responsible for relaxing the muscles and organs.

Important Parasympathetic Nervous System Functions

It has the following main functions:

  • It reduces the volume of the lungs
  • It decreases heart rate
  • Stimulation of the digestive process
  • Muscle relaxation
  • Constriction of the pupil
  • Stimulation of sexual arousal

Summary of article

Both sympathetic and parasympathetic are responsible for keeping our body in constant balance, while the sympathetic is responsible for activating alert functions when a stimulus produces stress, agitation or we perceive danger, the parasympathetic is the one that directs our body to a state of tranquility and conservation.

Others Related Biology Differences – Check Also

Related Articles

Leave a Reply

Your email address will not be published.

Back to top button