Search results
Results From The WOW.Com Content Network
The sympathetic nervous system's primary process is to stimulate the body's fight or flight response. It is, however, constantly active at a basic level to maintain homeostasis. [4] The sympathetic nervous system is described as being antagonistic to the parasympathetic nervous system.
The sympathetic division emerges from the spinal cord in the thoracic and lumbar areas, terminating around L2-3. The parasympathetic division has craniosacral "outflow", meaning that the neurons begin at the cranial nerves (specifically the oculomotor nerve, facial nerve, glossopharyngeal nerve and vagus nerve) and sacral (S2-S4) spinal cord.
The white ramus communicans (pl.: rami communicantes) from Latin ramus (branch) and communicans (communicating) is the preganglionic sympathetic outflow nerve tract from the spinal cord. Each of the thoracic, and the first and second lumbar nerves contribute a white ramus communicans to the adjoining sympathetic ganglion , unlike the gray rami ...
The sympathetic trunk is a fundamental part of the sympathetic nervous system, and part of the autonomic nervous system. It allows nerve fibres to travel to spinal nerves that are superior and inferior to the one in which they originated. Also, a number of nerves, such as most of the splanchnic nerves, arise directly from the trunks.
The bilaterally symmetric sympathetic chain ganglia, also called the paravertebral ganglia, are located just ventral and lateral to the spinal cord. [3] The chain extends from the upper neck down to the coccyx, forming the unpaired ganglion impar. Ganglia within this chain are either cervical, thoracic, lumbar, or sacral.
This is set in motion via the adrenergic (sympathetic) outflow from the brain, but the heart is unable to meet requirements because of the low blood volume, or decreased return. A feedback response to the medulla is triggered via the afferent vagus nerve. The high (ineffective) sympathetic activity is thereby modulated by vagal (parasympathetic ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
This stimulates an afferent limb which activates central nervous system pathways that in turn exert two different but synergistic autonomic effects on the body. First, global sympathetic outflow is reduced and, second, vagal outflow is increased.