ANATOMY OF THE AUTONOMIC NERVOUS SYSTEM Flashcards
What are the two major divisions of the autonomic nervous system (ANS)?
The two major divisions of the ANS are the sympathetic (thoracolumbar) division and the parasympathetic (craniosacral) division.
Where do motor neurons in the sympathetic division originate?
Motor neurons in the sympathetic division originate in nuclei within the CNS.
How do sympathetic preganglionic fibers exit the CNS?
Sympathetic preganglionic fibers leave the CNS through the thoracic, lumbar, and sacral spinal nerves.
What is the termination location of most thoracic and lumbar sympathetic preganglionic fibers?
Most thoracic and lumbar sympathetic preganglionic fibers terminate in ganglia located in the paravertebral chains.
What are the major ganglia associated with parasympathetic preganglionic fibers?
Major ganglia include the ciliary, pterygopalatine, submandibular, and otic ganglia.
Where do most parasympathetic preganglionic fibers terminate?
Most parasympathetic preganglionic fibers terminate on ganglion cells distributed diffusely or in networks in the walls of the innervated organs.
What is the enteric nervous system (ENS)?
The ENS is a large collection of neurons located in the walls of the gastrointestinal (GI) system, involved in both motor and secretory activities.
What are the two main plexuses of the enteric nervous system?
The two main plexuses of the ENS are the myenteric plexus (plexus of Auerbach) and the submucous plexus (plexus of Meissner).
How does the ENS function in relation to the autonomic nervous system?
The ENS functions in a semiautonomous manner, using input from the ANS for modulation of GI activity.
What is the difference between classic synapses and autonomic junctions?
Classic synapses are tight with short diffusion paths, while autonomic junctions release transmitters from a chain of varicosities and have wider junctional clefts.
What role do sensory fibers play in the autonomic nervous system?
Sensory fibers transmit chemical and mechanical information from the mucosa and stretch receptors to motor neurons and postganglionic neurons.
