parasympathetic ganglion

(noun)

The autonomic ganglia of the parasympathetic nervous system. Most are small terminal ganglia or intramural ganglia, so named because they lie near or within (respectively) the organs they innervate.

Related Terms

Examples of parasympathetic ganglion in the following topics:

  • Parasympathetic (Craniosacral) Division

    • Parasympathetic ganglia are the autonomic ganglia of the parasympathetic nervous system that lie near or within the organs they innervate.
    • Nerves that supply parasympathetic fibers to the parasympathetic ganglia of the head include the oculomotor nerve (ciliary ganglion); the facial nerve (pterygopalatine ganglion, submandibular ganglion); the glossopharyngeal nerve (otic ganglion); the vagus nerve (no named ganglion); and the pelvic splanchnic nerves (no named ganglion).
    • Parasympathetic ganglia are the autonomic ganglia of the parasympathetic nervous system, blue fibers).
    • These paired ganglia supply all parasympathetic innervation to the head and neck: ciliary ganglion (spincter pupillae, ciliary muscle), pterygopalatine ganglion (lacrimal gland, glands of nasal cavity), submandibular ganglion (submandibular and sublingual glands), and otic ganglion (parotid gland).
    • The nerves that supply parasympathetic fibers to the parasympathetic ganglia of the head include the oculomotor nerve (ciliary ganglion), the facial nerve (pterygopalatine ganglion, submandibular ganglion), the glossopharyngeal nerve (otic ganglion), the vagus nerve, and the pelvic splanchnic nerves.

  • Autonomic Ganglia

    • An example of parasympathetic ganglion is the ciliary ganglion, involved in pupil constriction and accommodation.
    • Parasympathetic ganglia are the autonomic ganglia of the parasympathetic nervous system.
    • The axons of presynaptic parasympathetic neurons are usually long.
    • Parasympathetic ganglia of the head (shown as red circles) help supply all parasympathetic innervation to the head and neck.
    • The pathways of the ciliary ganglion include sympathetic neurons (red), parasympathetic neurons (green), and sensory neurons (blue).

  • Divisions of the Autonomic Nervous System

    • Sympathetic and parasympathetic divisions typically function in opposition to each other.
    • The parasympathetic division functions with actions that do not require immediate reaction.
    • Many think of sympathetic as fight or flight and parasympathetic as rest and digest or feed and breed.
    • In the autonomic nervous system, preganglionic neurons connect the CNS to the ganglion.
    • Distinguish between the parasympathetic and sympathetic subsystems of the autonomic nervous system

  • Postganglionic Neurons

    • In the parasympathetic division, they are cholinergic and use acetylcholine as their neurotransmitter.
    • After this, it can then either create a synapse in this ganglion, ascend to a more superior ganglion, or descend to a more inferior paravertebral ganglion and make a synapse there, or it can descend to a prevertebral ganglion and create a synapse there with the postsynaptic cell.
    • The axons of presynaptic parasympathetic neurons are usually long.
    • As a result, the postsynaptic parasympathetic nerve fibers are very short.
    • The parasympathetic nervous system uses acetylcholine (ACh) as its chief neurotransmitter, although peptides (such as cholecystokinin) may act on the PSNS as a neurotransmitter.

  • Sympathetic Nervous System

    • This response is also known as the sympathetico-adrenal response because the pre-ganglionic sympathetic fibers that end in the adrenal medulla—like all sympathetic fibers—secrete acetylcholine.
    • The chain extends from the upper neck down to the coccyx, forming the unpaired coccygeal ganglion.
    • There are usually 21 or 23 pairs of these ganglia: 3 in the cervical region, 12 in the thoracic region, 4 in the lumbar region, 4 in the sacral region and a single, unpaired ganglion lying in front of the coccyx called the ganglion impar.
    • This intercostal nerve shows the sympathetic ganglion at the top left.
    • The parasympathetic nervous system, shown in blue, is a division of the autonomic nervous system.

  • Autonomic Interactions

    • Sympathetic and parasympathetic divisions typically function in opposition to each other.
    • The parasympathetic division functions with actions that do not require immediate reaction.
    • Consider sympathetic as fight or flight and parasympathetic as rest and digest or feed and breed.
    • Some typical actions of the sympathetic and parasympathetic systems are listed below.
    • In the autonomic nervous system, preganglionic neurons connect the CNS to the ganglion.

  • Parasympathetic Responses

    • The parasympathetic nervous system regulates organ and gland functions during rest and is considered a slowly activated, dampening system.
    • The sympathetic and parasympathetic divisions typically function in opposition to each other.
    • The parasympathetic nervous system may also be known as the parasympathetic division.
    • When stimulated, the preganglionic nerve releases ACh at the ganglion, which acts on nicotinic receptors of the postganglionic neurons.
    • The parasympathetic nervous system, shown in blue, is a division of the autonomic nervous system.

  • Preganglionic Neurons

    • In the autonomic nervous system (ANS), fibers from the central nervous system to the ganglion are known as preganglionic fibers.
    • Sympathetic preganglionic fibers tend to be shorter than parasympathetic preganglionic fibers because sympathetic ganglia are often closer to the spinal cord while parasympathetic preganglionic fibers tend to project to and synapse with the postganglionic fiber close to the target organ.
    • The prevertebral ganglia celiac ganglion, aorticorenal ganglion, superior mesenteric ganglion, inferior mesenteric ganglion.
    • Whereas in the parasympathetic division there is a divergence factor of roughly 1:4, in the sympathetic division there can be a divergence of up to 1:20.
    • Pre- and post-ganglionic fibers and targets are depicted.

  • Autonomic Nervous System

    • The autonomic nervous system, the relay between the CNS and internal organs, is divided into the sympathetic and parasympathetic systems.
    • A preganglionic neuron (originating in the CNS) synapses to a neuron in a ganglion that, in turn, synapses on the target organ .
    • One way to remember this is to think that during a restful situation like a picnic, the parasympathetic nervous system is in control ("picnic" and "parasympathetic" both start with "p").
    • Autonomic responses are mediated by the sympathetic and the parasympathetic systems, which are antagonistic to one another.
    • The sympathetic and parasympathetic nervous systems often have opposing effects on target organs.

  • Autonomic Plexuses

    • Autonomic plexuses are formed from sympathetic and parasympathetic fibers that innervate and regulate the overall activity of visceral organs.
    • Autonomic plexuses are formed from sympathetic postganglionic axons, parasympathetic preganglionic axons, and some visceral sensory axons.
    • A small ganglion, the cardiac ganglion of Wrisberg, is occasionally found connected with these nerves at their point of junction.