Pain - Lateral Spino Thalamic tracts

Free nerve endings - A delta and C fibres.

 A delta - unmyelinated - fast - sharp

C - myelinated - slow - dull/burning

go to subsantia gelatinosa - (modulates sensory input acc gate control theory) in dorsal horn of spinal cord thru Lissauer's tracts 

Decussate and ascend contra laterally and reach thalamus mainly and other parts of brain.

Ganglia of cranial nerves

Facial nerve - geniculate ganglion
Smilunar / gasserian / trigemina ganglion - sensory nucleus of trigeminal nerve

parasympathetic ganglia of head and neck

CN 3 - Ciliary ganglia -  Preganglionic axons from theEdinger-Westphal nucleus travel along the oculomotor nerve and form synapses with these cells. Thepostganglionic axons run in the short ciliary nerves and innervate two eye muscles:

• the sphincter pupillae constricts the pupil, a movement known as Miosis. The opposite, Mydriasis, is the dilation of the pupil.
• the ciliaris muscle contracts, releasing tension on the Zonular Fibers, making the lens more convex, also known as accommodation.

CN 7 - Sub Mandibular ganglion - 

• Preganglionic parasympathetic fibers from the superior salivatory nucleus of the medulla oblongata, via the chorda tympani and lingual nerve, which synapse at the origin of:
• Postganglionic parasympathetic fibers to the oral mucosa and the submandibular and sublingual salivary glands.They are secretomotor to these glands.

CN - 7 Pterygo Palatine Ganglion - 

Pre ganglionic -  nervus intermedius (a part of the facial nerve) through the greater petrosal nerve.

Post ganglionic -  trigeminal nerve to the mucous membrane of the nose, soft palate, tonsils, uvula, roof of the mouth, upper lip and gums, and upper part of the pharynx. It also sends postganglionic parasympathetic fibers to the lacrimal nerve (a branch of the Ophthalmic nerve, also part of the trigeminal nerve) via the zygomatic nerve, a branch of the maxillary nerve (from the trigeminal nerve), which then arrives at the lacrimal gland.

CN 9 - Otic ganglion - lesser petrolar nerve from inferior salivatory nucleus to parotid gland from glosso pharyngeal nerve throught auriculo temporal.