Autonomic Nervous System
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
peripheral nervous system = autonomic and somatic nervous systems
efferent autonomic nervous system is divided into sympathetic and
parasympathetic outflows
Sympathetic
Efferent
 Anatomy
o preganglionic cells in lateral horns of T1-L2
o postganglionic – usually located away from target organ ie paravertebral
ganglia, collateral ganglia (exception is suprarenal gland)
o white rami (myelinated – T1 to L2only) – located more distal, contains
preganglionic and afferent fibres
o gray rami (unmyelinated) – efferent postganglionic fibres
o in the neck
 superior cervical ganglion – union of upper 4 cervical ganglia
 middle cervical ganglion – C5 and C6
 inferior cervical ganglion (stellate) – C7, C8 and often T1
 Physiology
o Preganglionic
 nicotinic Ach receptors
o Postganglionic
 NorAdr adrenoreceptor
 Exceptions
1. Sweat gland - muscarinic Ach
2. Adrenal medulla – release Adr(80%) and NorAdr (20%)
 Function
o For amplification of outflow and widespread discharge during times of
stress, fear, anger (flight or fright)
o Thermal regulation
 Vasomotor
 Sudomotor - sweat
 Pilomotor
o Cardiac rhythm
o Adrenal medulla
Afferent
 Anatomy
o Cell bodies in the posterior root ganglia of spinal nerves
o Hitchhikes along with sympathetic efferent fibres and enter white ramus
communicans to posterior root ganglia
 Function
o Visceral pain
Parasympathetic
 Anatomy
o preganglionic in cranial nerve nuclei, lateral horn cells of sacral segments
o postganglionic – usually located close to target organ (terminal ganglia)


Physiology
o Preganglionic
 nicotinic Ach receptors
o Postganglionic
 Muscarinic Ach receptor
Function
o Supplies viscera only - discrete regulation of organ function and
conservation of resources (feed or breed)
Cranial Parasympathetic Ganglia
Each ganglia consists of parasympathetic, sympathetic and sensory branches
Ciliary ganglion
Parasympathetic
Edinger Westphal nucleus (part of CN3 nucleus)
Midbrain (periaqueductal gray matter)
Inferior Division of CN III
Superior Orbital Fissure
Ciliary ganglion
Short ciliary nerves
Supplies sphincter pupillae of the iris and the ciliary muscles of the lens
Sympathetic
Superior cervical ganglion
Internal carotid nerve
Long and short ciliary nerves
Internal carotid/ophthalmic artery
Sensation
Nasociliary nerve branch
Long root of the ciliary ganglion
Short ciliary nerve
NB – long ciliary nerve is direct branch from nasociliary nerve to eye, does not pass
through ciliary ganglion – contains sympathetic and sensory nerves
Pterygopalatine ganglion
Parasympathetic
Superior Salivary ganglion
Nervus intermedius part of Facial nv
Geniculate ganglion
Greater petrosal nerve
Nv of pterygoid canal (with deep petrosal) nv
Pterygopalatine ganglion
Nasopalatine nerve
Lateral posterior superior nasal
Greater palatine
Lesser palatine
Pharyngeal nerve
Orbital branches
Zygomatic nerve
Lacrimal nerve
Ventrolateral part of pons
Intratemporal
Hiatus of GPN
Pterygoid (Vidian) canal (foramen lacerum)
Pterygopalatine fossa
Sphenopalatine foramen
Sphenopalatine foramen
Greater palatine foramen
Lesser palatine foramen
Palatovaginal canal
Inferior orbital fissure
Sympathetic
Superior cervical ganglion
Internal carotid nerve
Deep petrosal nerve
Nv of pterygoid canal (with deep petrosal) nv
Foramen lacerum
Pterygoid (Vidian) canal (foramen lacerum)
Sensation
Maxillary nerve
Otic ganglion
Parasympathetic
Inferior Salivary ganglion
Glossopharyngeal nerve
Tympanic branch (Jacobsen’s)
Tympanic plexus
Lesser petrosal nerve
Ventrolateral part of pons
Jugular foramen
tympanic caniliculus
promontory, middle ear
Hiatus of LPN
Otic ganglion
Auriculotemporal nerve
Foramen ovale/petrosal foramen
Sympathetic
Superior cervical ganglion
External carotid artery
Maxillary artery
Middle meningeal artery
Sensation
Auriculotemporal nerve
Motor
Nerve to medial pterygoid, fibres to tensor tympani and tensor palati
Submandibular ganglion
Parasympathetic
Superior Salivary ganglion
Nervus intermedius part of Facial nv
Geniculate ganglion
Chorda tympani
Lingual nerve
Submandibular ganglion
Sympathetic
Superior cervical ganglion
External carotid artery
Facial artery
Middle meningeal artery
Sensation
Lingual nerve
Ventrolateral part of pons
Intratemporal
Petrotympanic fissure (canal of Huguier)