Parasympathetic nervous system

Question 1

4 nuclei of cranial parasympathetic system hat supply head and neck

Answer 1

1. Visceral oculomotor nucleus (Edinger-Westphal nucleus)
2. Superior salivatory nucleus
3. Inferior salivatory nucleus
4. Dorsal vagal nucleus

Question 2

Course of Visceral oculomotor nucleus (Edinger-Westphal nucleus)

Answer 2

• Pre-ganglionic fibres: Parasympathetic fibers Travels with the motor root of the oculomotor nerve to reach the ciliary ganglion supplied by fibers from the Edinger-Westphal nucleus
• Post-ganglionic fibers:

The parasympathetic fibers leaves the ciliary ganglion & travels via the short ciliary nerves

=> continue into the orbit

=> innervate structures of the eyes

• Target Organs: The post-ganglionic fibres from the ciliary ganglion innervate the sphincter pupillae (contracts the pupil) and the ciliary muscles (accommodates for near vision).

Question 3

The course of Superior salivatory nucleus (VII) (with pterygopalatine ganglion)

Answer 3

• Pre-ganglionic fibres:

These Parasympathetic fibers travels with the greater petrosal nerve and the nerve of pterygoid canal

=> to reach the pterygopalatine ganglion supplied by fibers from the superior salivatory nucleus (associat- ed with the facial nerve).

• Post-ganglionic fibres:

The parasympathetic fibre hitchhikes on branches of the maxillary nerve (V/2)
(Maxillary nerve ’ zygomatic nerve ’ anastomosis ’ lacrimal nerve)

• Target organs:

The post-ganglionic fibres from the pterygopalatine ganglion provide secretomotor innervation to lacrimal gland, palate glands and nasal cavity

Question 4

Describe parasympathetic supply from mandibular ganglion
- Superior salivatory nucleus (VII)

Answer 4

• Pre-ganglionic fibres:

These Parasympathetic fibers are Travels within the chorda tympani, a branch of the facial nerve

=> This nerve hitch-hikes along the lingual branch of the mandibular nerve (V/3) to reach the mandibular ganglion supplied by fibres from the superior saliva- tory nucleus (associated with the facial nerve).

• Post-ganglionic fibres:

Fibres leave the ganglion and travel directly to the submandibular and sublingual glands.

• Target Organs:

Secretomotor innervation to the submandibular and sublingual salivary glands.

Sympathetic fibres from the facial artery plexus pass through the submandibular ganglion.

=> They are thought to innervate glands in the base of the oral cavity.

Question 5

Describe parasympathetic supply from otic ganglion - inferior salivatory nucleus

Answer 5

• Pre-ganglionic fibres:

Parasympathetic fibres travel within tympanic nerve (glossopharyngeal nerve), the lesser petrosal nerve => to reach the otic ganglion supplied by fibres from inferior salivatory nucleus (associated with the glossopharyngeal nerve).

• Post-ganglionic fibres:

The parasympathetic fibres Hitchhikes on the auriculotemporal nerve (branch of the mandibular division of the trigeminal nerve)

=> provide secretomotor innervation to the parotid gland.

• Target Organs: The post-ganglionic fibres from the otic ganglion provide innervation to the parotid gland

Question 6

Describe parasympathetic supply from intramural ganglion
- Dorsal vagal mo- tor nucleus (vagus nerve

Answer 6

• Pre-ganglionic fibres:

Parasympathetic fibres travel within the vagus nerve => to reach the intramural ganglion supplied by fibres from dorsal vagal motor nucleus (vagus nerve)

• Post-ganglionic fibres: N/A
• Target Organs: Smooth muscle and gland