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autonomic nervous system
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Diagram of the autonomic nervous system showing the sympathetic and parasympathetic divisions. The left side illustrates sympathetic nerves branching from the spinal cord to organs and glands, while the right side shows parasympathetic nerves connecting to organs such as the eye, heart, lungs, liver, stomach, intestines, and bladder. Color-coded pathways and labeled ganglia highlight the different nerve routes and target organs in human anatomy. Diagram showing the organization of the autonomic nervous system, with labeled pathways for parasympathetic and sympathetic nerves, highlighting synapses, neurotransmitters like acetylcholine and norepinephrine, and their receptor types.
How does the autonomic nervous system maintain homeostasis?
autonomic nervous system
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Walter Rudolf Hess
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Diagram of the autonomic nervous system showing the sympathetic and parasympathetic divisions. The left side illustrates sympathetic nerves branching from the spinal cord to organs and glands, while the right side shows parasympathetic nerves connecting to organs such as the eye, heart, lungs, liver, stomach, intestines, and bladder. Color-coded pathways and labeled ganglia highlight the different nerve routes and target organs in human anatomy.
autonomic nervous system Schematic representation of the autonomic nervous system, showing distribution of sympathetic and parasympathetic nerves to the head, trunk, and limbs.

autonomic nervous system

anatomy
Also known as: ANS, vegetative nervous system, visceral nervous system(Show More)
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autonomic nervous system, in vertebrates, the part of the nervous system that controls and regulates the internal organs without any conscious recognition or effort by the organism. The autonomic nervous system comprises two antagonistic sets of nerves, the sympathetic and parasympathetic nervous systems. The sympathetic nervous system connects the internal organs to the brain by spinal nerves. When stimulated, these nerves prepare the organism for stress by increasing the heart rate, increasing blood flow to the muscles, and decreasing blood flow to the skin. The nerve fibres of the parasympathetic nervous system are the cranial nerves, primarily the vagus nerve, and the lumbar spinal nerves. When stimulated, these nerves increase digestive secretions and reduce the heartbeat.

This article was most recently revised and updated by Kara Rogers.