Table of ContentsView AllTable of ContentsAnatomyFunctionControl of the Autonomic Nervous System
Table of ContentsView All
View All
Table of Contents
Anatomy
Function
Control of the Autonomic Nervous System
Your nervous system helps you regulate your voluntary and involuntary actions, as well as thinking, communicating, and memory. Your autonomic nervous system is the aspect of the nervous system that controls all of your vital functions, like breathing, digestion, and heart rate—many of which you aren’t consciously aware of. In short, it keeps you alive.
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It’s probably a good thing that your autonomic nervous system is out of your conscious control. If you fall when learning to walk, you may temporarily injure yourself, but you generally learn how to pick yourself up and start again. Can you imagine if you had to learn how to speed up your heart whenever you needed to? Or if you stopped breathing every time you forgot to breathe?
While few diseases attack the autonomic nervous system alone, almost all medical disorders have some impact on autonomic functions.
Autonomic Nervous System Anatomy
Your autonomic nervous system includes a craniosacral parasympathetic portion and a thoracolumbar part sympathetic portion. These are sometimes thought of as being opposite to each other, ultimately striking a balance within the body.
The sympathetic and parasympathetic functions:
The nerves of the autonomic nervous systemsynapsein a clump of nerves called aganglionbefore the message is transmitted to the target organ, such as a salivary gland. This allows for another level of communication and control.
Function of the Autonomic Nervous System
The autonomic nervous system has many functions. The parasympathetic system performs basic housekeeping and controls things when you are at rest. The sympathetic system is the emergency system and helps you carry out life-saving flight or fight responses.
The Parasympathetic
Many nerves of the parasympathetic portion of the autonomic nervous system begin in the nuclei in your brainstem. From there, they travel throughcranial nervessuch as thevagus nerve, which slows the heart rate, or the oculomotor nerve, which constricts the pupil of the eye. Parasympathetic stimulation also causes your eyes to tear and your mouth to salivate.
Other parasympathetic nerves terminate in the walls of thoracic and abdominal organs like the esophagus, gastrointestinal tract, pharynx, heart, pancreas, gallbladder, kidney, and ureter. The sacral parasympathetic nerves synapse in ganglia in the walls of the colon, bladder, and other pelvic organs.
The Sympathetic
Sympathetic fibers of the autonomic nervous system exit the lateral (side) part of your spinal cord. They receive information from parts of the brain such as the brainstem and thehypothalamus.
Fibers run from synapses in ganglia just outside the spinal column to their targets, usually along blood vessels. For example, the sympathetic nerves that dilate your pupils exit the spinal cord in your neck and synapse in the ganglion called the superior sympathetic ganglion, they then run along the carotid artery to your face and eye. The sympathetic nervous system supplies nerves to the abdominal and pelvic visceral organs, as well as hair follicles, sweat glands, and more.
Autonomic Neurotransmitters
The nervous system communicates through chemical messengers called neurotransmitters. Neurotransmitters likeacetylcholineandnorepinephrineare primarily responsible for communication in your autonomic nervous system.
Blood Pressure Control
Blood pressureis a good example of how the sympathetic and parasympathetic components of the nervous system work together within the body. In general, there are two main things that cause blood pressure to go up: The speed and force of your pumping heart, and the narrowness of the blood vessels in your body.
Most of the time, your autonomic nervous system works very well. However, the fight or flight response may become activated with small everyday stresses, releasing a lot of the stress hormone cortisol and driving your blood pressure and heart rate up unnecessarily.
For most of us, the autonomic nervous system is generally out of our conscious control. Inthe brainstem, the nucleus tractus solitarius is the main command center for the autonomic nervous system, sending input largely through cranial nerves IX and X.
Thecerebral cortexof your brain, normally associated with conscious thought, can change your autonomic nervous system to some degree—usually involuntarily, but sometimes voluntarily. In the cerebral cortex, the insula, anterior cingulate cortex, substantia innominata, amygdala, and ventromedial prefrontal cortex are areas that help you understand the events that are going on around you, as well as your emotions. These regions communicate with your hypothalamus to impact the actions of your autonomic nervous system.
Voluntary Control of the Autonomic Nervous System
Because the cerebral cortex is linked to the autonomic nervous system, you may be able to control your autonomic nervous system through conscious effort, especially with some practice. Practices like yoga, mindfulness, and meditation can help you manage your physical autonomic nervous system activity.
Highly trained people, such as advanced yoga practitioners, may be able to intentionally slow their heart rate or even control their body temperature. Mindfulness and meditation can have similar effects.
For most of us, though, focusing on things that are relaxing rather than stressful, or just taking a slow, deep breath when you notice that you’re feeling anxious or your heart is racing can bring your autonomic nervous system back into a degree of control.
Stress Therapy Treatment
SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Adams and Victor’s Principles of Neurology, 9th ed: The McGraw-Hill Companies, Inc., 2009.Blumenfeld H, Neuroanatomy through Clinical Cases. Sunderland: Sinauer Associates Publishers 2002.
Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Adams and Victor’s Principles of Neurology, 9th ed: The McGraw-Hill Companies, Inc., 2009.Blumenfeld H, Neuroanatomy through Clinical Cases. Sunderland: Sinauer Associates Publishers 2002.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Adams and Victor’s Principles of Neurology, 9th ed: The McGraw-Hill Companies, Inc., 2009.Blumenfeld H, Neuroanatomy through Clinical Cases. Sunderland: Sinauer Associates Publishers 2002.
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