The Nervous System

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The Nervous System

The nervous system is an information pathway. This information travels from the receptors to and from the brain. Refer to figure 1. 

The central nervous system (CNS) controls and coordinates the nervous system and is comprised of the brain and spinal cord [1]. 

The peripheral nervous system (PNS) consists of the remaining nerves that fan out throughout the body. The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system [1].

The somatic nervous system is responsible for all voluntary functions and connecting the CNS to sensory receptors [1]. 

The autonomic nervous system controls automatic, involuntary functions heart rate, digestion, temperature, and breathing [1]. It is made up of two important divisions. 

The two divisions are the sympathetic and parasympathetic divisions. The sympathetic division activates the body’s ‘fight or flight‘ system in response to stress, mobilizing the body’s resources for emergencies. Epinephrine and norepinephrine are released. This prompts bodily changes like heart rate increase, pupil dilation, lung capacity increase, etc. Every organ in the body is modified to meet danger. This prepares the body to respond to emergencies, strong emotions, and strenuous activities [1]

The parasympathetic division is responsible for ‘resting and digesting’ and is activated when experiencing relaxation where there is no perceived threat, conserving bodily resources. This brings the body down from a heightened state of stress into a more normal state. It antagonizes the sympathetic nervous system. It controls the body under normal circumstances. One way to activate the parasympathetic nervous system is to control your breathing [1,2]. 

  1. Weiten, W., McCann, D., & Matheson, D. H. (2022). Psychology: Themes and variations. Cengage. 85-89
  2. Yuan, H., & Silberstein, S. D. (2016). Vagus Nerve and Vagus Nerve Stimulation, a Comprehensive Review: Part I. Headache56(1), 71–78. https://doi.org/10.1111/head.12647

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