Sympathetic Nervous System

Sympathetic Nervous System

How does your body respond to stressful situations? Have you ever wondered how your heart suddenly beats rapidly and you break out into a sweat when you encounter some form of danger? It’s almost an automatic response that occurs whenever you sense a threat to well-being, whether it is just a potential embarrassing situation or a really scary situation such as an attack by a stranger. This fight-or-flight response is brought about by your sympathetic nervous system, which usually helps you deal with stress.

Part 1: What Is the Sympathetic Nervous System?

While your brain, which is part of the central nervous system, has the capability to control your conscious actions like walking, thinking, and talking, your

It consists of the sympathetic nervous system and the parasympathetic nervous system. The primary function of the sympathetic system is to stimulate your fight-or-flight response, while the parasympathetic system enables you to maintain normal functions such as digesting and keeping the body at rest.

Part 2: The Structure of the Sympathetic Nervous System

Transmission of signals in the sympathetic nervous system is accomplished through a network of nerve cells called neurons. There are two types of neurons – the preganglionic neurons have short fibers that originate from the spinal cord’s thoracolumbar segments, which communicate with ganglia adjacent to the spinal column, and synapse with the longer postganglionic neurons.

Preganglionic neurons synapse with ganglia and release a chemical (neurotransmitter) called acetylcholine, which activates receptors on the postganglionic neurons. The postganglionic neurons in turn release a hormone called norepinephrine, which targets adrenergic receptors on various organs and tissues. Stimulation of these target receptors result in the characteristic fight-or-flight

The first consists of postganglionic neurons found in the sweat glands in most areas of the body discharge acetylcholine to activate muscarinic receptors, except for the palms and soles of the feet. In these areas, norepinephrine acts on the adrenergic receptors. The second exception consists of the chromaffin cells found in the adrenal medulla, which are equivalent to postganglionic neurons. Preganglionic neurons communicate with the chromaffin cells and stimulate them to release epinephrine and norepinephrine directly into your blood.

Part 3: Two Hormones Behind the Sympathetic Nervous Activation

The sympathetic nervous system releases two hormones within the body in response to stress, resulting in an 'adrenaline rush,' or a sense of urgency that occurs during stressful conditions. These hormones are called epinephrine and norepinephrine, which help your body perform optimally during such events.

Upon activation of your sympathetic nervous system, norepinephrine is released to prepare the body for the initial stages of stress. If the stress is quickly resolved, the body functions return to normal. However, if the stressful event persists, your body produces epinephrine to increase these effects and activate various parts of the body to react