Sympathetic Reflex
Sympathetic Reflex - Related Videos
01:25
The Sympathetic Nervous System
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2019
Overview The sympathetic nervous system—one of the two major divisions of the autonomic nervous system—is activated in times of stress. It prepares the body to meet the challenges of a demanding circumstance while inhibiting essential body functions—such as digestion—that are a lower priority at the moment. The “Fight or Flight” System As a student, you may have had the experience of walking into class and finding a surprise exam that you were not expecting. In the moment of realization, you...
09:52
Inducing Dendritic Growth in Cultured Sympathetic Neurons
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Cited by 10 •
2012
We describe a protocol for using bone morphogenetic protein-7 (BMP-7) or Matrigel to selectively induce dendritic growth in primary sympathetic neurons dissociated from the superior cervical ganglia (SCG) of perinatal rats.
07:00
Generating Postganglionic Sympathetic Neurons from Human Pluripotent Stem Cells
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2025
This video demonstrates an in vitro method to generate postganglionic sympathetic neurons from human pluripotent stem cells (hPSCs). hPSCs are differentiated into neural crest cells (NCCs) on a basement membrane matrix support using a differentiation medium. The NCCs are then dissociated and formed into spheroids using another differentiation medium. Finally, the spheroids are transformed into postganglionic sympathetic neurons using a sympathetic neuron medium.
01:31
Sympathetic Signaling
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2025
Sympathetic signaling, a vital part of the autonomic nervous system, plays a crucial role in mobilizing the body's resources in response to stress or emergencies. It involves the transmission of nerve impulses from sympathetic preganglionic fibers to postganglionic fibers. This results in the release of specific neurotransmitters and activation of adrenergic receptors. Sympathetic preganglionic fibers release the neurotransmitter acetylcholine (ACh) onto the ganglionic neurons in the...
11:49
Protocol for Culturing Sympathetic Neurons from Rat Superior Cervical Ganglia (SCG)
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Cited by 44 •
2009
This is a protocol describing how to isolate and culture primary sympathetic neurons from superior cervical ganglia (SCG) of newborn rat pups.
FAQs
The sequence begins when a sensory receptor detects a change, such as reduced blood pressure, pain, or temperature. Signals then travel to the spinal cord, which organizes sympathetic output through postganglionic neurons. Their activity alters target tissues, allowing the response to adjust internal organs and blood vessels rather than producing a conscious, voluntary action.
Postganglionic neurons provide the direct link to target tissues by releasing norepinephrine. In some responses, the adrenal medulla adds a second route by releasing hormones that amplify sympathetic effects. This distinction helps explain why a reflex can combine localized signaling at organs with broader support for changes such as heart activity, blood flow, pupil size, and digestive activity.
Sympathetic pathways distribute their effects across different targets, including the heart, blood vessels, pupils, and digestive organs. As a result, one response can increase heart rate, redirect blood flow, dilate the pupils, and reduce digestive activity in a coordinated pattern. This broad action helps the body adjust internal conditions during stress or changing physiological demands.
Begin with the triggering condition, such as pain, reduced blood pressure, or a temperature shift. Next, follow sensory signaling to the spinal cord, then trace activation of postganglionic neurons and, where relevant, the adrenal medulla. Finally, connect norepinephrine or adrenal hormone activity with the resulting organ and blood-vessel changes.
In cardiovascular regulation, these reflexes connect detected changes such as reduced blood pressure with adjustments involving heart activity and blood vessels. In thermoregulation, temperature shifts can provide the sensory input that initiates sympathetic pathways. Studying both contexts shows how the same autonomic system helps maintain internal stability under different physiological conditions.
The pathways provide several observable functional outcomes, including changes in heart rate, blood flow, pupil diameter, and digestive activity. Researchers can relate these effects to the initiating stimulus, spinal signaling, postganglionic activity, and adrenal participation. This framework supports investigation of disorders involving autonomic nervous system function without treating any single response as an isolated event.