Posted by lae2 on October 09, 2011 at 20:49:08:
We have been introduced the parasympathetic ganglia during the course of various lectures. We shall hone in on them this week. Please be familiar with Cranial Nerve Plates for III, VII, and IX with regards to the anatomy of the parasympathetic ganglia of the head - the COPS.
The following Gray's figure is an integrated depiction of the Ciliary, Otic, Pterygopalatine, and Submandibular ganglia.
Observe: Each ganglion has a preganglionic parasympathetic motor root, a postganglionic sympathetic root, a sensory root from trigeminal. Each ganglion elaborates postganglionic parasympathetic fibers onto a trigeminal pathway.
The location for all postganglionic cell bodies of the sympathetic division of the autonomic nervous system that contribute to the head is the superior cervical sympathetic trunk ganglion. Postganlionic fibers from the superior cervical sympathetic trunk ganglion form internal and external carotid nerves that, in turn, ramify to form perivascular autonomic plexuses that follow the internal and external carotid arterial trees. The deep petrosal nerve is a named nerve of postganglionic sympathetic fibers derived from the internal carotid plexus. Thus, the postganglionic cell bodies that contribute fibers to the deep petrosal nerve are located in the superior cervical ganglion. The preganglionic fibers are located in the intermediolateral cell columns of spinal cord levels T1-4 (see Typical Spinal Nerve from the cranial nerve handout). Pseudoephredrine is agonistic to the activities of these fibers that, for example, follow the superior, middle, and inferior lateral posterior nerves and thereby promote decongestion.
Meanwhile, preganglion parasympathetic fibers travel with cranial nerves III, VII, and IX. Their cell bodies are located in the CNS. Note the location of the preganglionic cell bodies on your cranial nerve handouts as you study the following figure. The postganglionic cell bodies are held by the COPS.
Something else to be aware of. Notice the sympathetic fibers entering the submandibular gland directly off the facial arterial plexus. This was demonstrated Friday in the dissection laboratory in the North room about two tables from the window on the North wall. Of the salivary glands, the submandibular gland is the only one that directly responds to sympathetic tone. This response is to irritation. If you are a runner (or visiting the dentist) and run with your mouth open you have noticed how viscous your saliva becomes. This is a response to irritation involving GSA sensation (dry and cold mucosa) and GVE secretomotor. Please try to run with your mouth closed. Your lungs will like you for the warm air and you won't be spitting out grossly viscous saliva on your competitors.
Please have a "feeling" for the COPS by the time of Wednesday's lecture.
