autonomic neuron sympathetic neuron https://cellxgene.cziscience.com/cellguide/CL_0011103 Sympathetic neurons are a distinct class of neurons that are an integral part of the autonomic nervous system, specifically within the sympathetic division. They play a critical role in the body's 'fight or flight' responses and are primarily involved in regulating involuntary physiological processes, such as heart rate, blood pressure, body temperature, and metabolic processes. These neurons are essential for homeostatic mechanisms, working to ensure a balanced state is maintained within the body amidst changing environments. Structurally, sympathetic neurons are characterized by their relatively long axons, which allow them to relay signals from the central nervous system to various peripheral organs and tissues. They typically originate within the spinal cord's thoracic and lumbar regions, extending their axons to connect with various targets, including cardiac muscle, smooth muscle, and glands. These neurons often utilize noradrenaline (norepinephrine) as a neurotransmitter, which binds to adrenergic receptors on the target cells to exert their effects. Functionally, the sympathetic neurons help the body respond to stressful or threatening situations. When activated, they provoke a cascade of processes that ready the body for quick action. This includes accelerating the heart rate, dilating the pupils, slowing digestion, and increasing blood flow to muscles. Conversely, when the threat has passed, they encourage a return to normalcy by inhibiting these same processes. Beyond this 'fight or flight' response, sympathetic neurons also function to help regulate body temperature by inducing sweating or shivering, influence the dilation of blood vessels to control blood pressure, and can stimulate the release of glucose from the liver to provide energy. Overall, sympathetic neurons are key mediators of the body's response to various internal and external stimuli, maintaining homeostasis and preparing the body for diverse challenges. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) ZFA:0005777 Sympathetic neurons are part of the sympathetic nervous system and are primarily adrenergic producing the neurotransmitter noradrenalin along with other neuropeptides. Homo sapiens