AUTONOMIC NERVOUS SYSTEM
is concerned with inervation of the inner organs
– unstrip ped muscles in the walls of organs
– glandular cells and glands
– heart
– unstripped muscles in the walls of vessels (only Symp.)
– smooth muscles attached to the hairs (only S)
– sweat glands (only S)
Efferents of autonomic peripheral nerves are composed ot two neurons:
- preganglionic neuron – lies in the CNS
- postganglionic neuron – contained in the autonomic ganglia
preganglionic neurons - lower autonomic centres
hypothalamus - higher autonomic centre
higher and lower autonomic centres are connected by reticular formation (hypothalamoreticular and reticulospinal tracts)
PARASYMPATHETIC – CRANIOSACRAL PART of the autonomic system
preganglionic neurons are placed in:
- the brainstem – PS nuclei of cranial nerves
- the spinal cord - intermediolateral nuclei in the 2nd- 4th sacral spinal segments
SYMPATHETIC – THORACOLUMBAR PART of the autonomic system
preganglionic neurons lie in the spinal cord
- intermediolateral nuclei of the thoracic and upper lumbar spinal segments (C8 – L3)
PARASYMPATHETIC SYSTEM
preganglionic fibres are contained in 3rd, 7th, 9th and 10th cranial nerves and 2nd – 4th sacral nerves
1. OCULOMOTOR NERVE
PS fibres arise from the nucleus of oculomotor n. (Edinger-Westphal nucleus)→synaps in the
ciliary ganglion - postganglionic fibres run in the ciliary nerves to supply sphincter pupillae
and ciliaris muscles
2. FACIAL NERVE
• PS fibres leave the lacrimal nucleus - are carried by the greater petrosal nerve, synaps in the
pterygopalatine ganglion - run in the infraorbital, zygomatic and lacrimal nerves – supply
lacrimal gland
and nasal and palatal glands
• PS fibres start in the superior salivary nucleus - run in the chorda tympani and lingual nerve –
synaps in the submandibular ganglion – supply submandibular and sublingual glands
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3. GLOSSOPHARYNGEAL NERVE
PS fibres arise from the inferior salivary nucleus – run in the tympanic nerve (tympanic plexus)
and lesser petrosal nerve – synaps in the otic ganglion and finally are brought by
auriculotemporal nerve – supply parotid gland
4. VAGUS NERVE
PS nucleus of vagus - dorsal nucleus - the nerve gives of pulmonary, cardiac, oesophageal,
gastric, intestinal branches – terminate in the minute ganglia in the walls of organs
supply: - thoracic and abdominal organs (except left colic flexure, descending and sigmoid
colon)
- gonads
5. SACRAL PARASYMPATHETIC PART
PS fibres arise from the intermediolateral nucleus of the 2nd – 4th sacral segments run in the 2nd
– 4th sacral nerves – leave them as pelvic splanchnic nerves → join sympathetic pelvic plexus –
synaps in the minute ganglia in the pelvic plexus or in the walls of organs
supply: pelvic organs (except gonads – these are supplied by vagus n.)
sigmoid and descending colon, left colic flexure
SYMPATHETIC PART OF AUTONOMIC NERVOUS SYSTEM
preganglionic neurons lie in the intermediolateral nucleus of thoracic and upper three (four)
lumbar spinal segments
axons – preganglionic fibres run in the spinal nerves –leave them as white communicating
rami – enter ganglia of sympathetic trunk
ganglia contain postganglionic neurons – send postganglionic fibres which pass:
1. as grey communicating rami to the spinal nerves – to supply sweat gands and vessels
2. as visceral nerves – to supply organs – mainly the heart
3. as plexusses around the arteries – to supply organs of the head, neck, thorax, abdomen and
pelvis
SYMPATHETIC TRUNK
is composed of 21 – 23 sympathetic ganglia : 3 cervical, 10 – 11 thoracic, 4 lumbar, 4 – 5 sacral
1 coccygeal
ganglia are connected one to another by interganglionic rami to form
subdivided into the cervical, thoracic, lumbar and sacral part
sympathetic trunk
Cervical part
superior, middle and inferior (cervicothoracic) ganglia receive preganglionic fibres from C8-Th2
segments via interganglionic rami
Superior cervical ganglion
lies behind the int. carotid a. - in front of C2,3 vertebrae
sends:
l. grey communicating rami to the 1st - 4th cervical nerves
2. internal carotid nerve → surrounds int. carotid artery - internal carotid plexus and its
branches.
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3. superior cervical cardiac nerve
4. external carotid nerves - ext. carotid plexus → accompanies ext. carotid artery and its
branches
5. jugular nerve and laryngopharyngeal branches → sympathetic fibres to the IX. and X. nerves
Middle cervical ganglion
the smallest, lies in front of C6, behind the inf. thyroid a.
sends:
1. grey communicating rami to C5,6 spinal nerves
2. inf. thyroid plexus
3. middle cardiac cervical nerve
Cervicothoracic ganglion (ganglion stelatum)
lies in front of C7 vertebra, behind the vertebral a.
is connected with the middle ganglion by „ansa subclavia“
sends:
l. grey communicating rami to C7,8 and TH1 spinal nerves
2. subclavian plexus ( inferior thyroid, vertebral.....)
3. inferior cardiac nerves
Thoracic part
11 thoracic ganglia - interconnected to form thoracic sympathetic trunk
receive white communicating rami from the thoracic spinal nerves
send:
l. grey communicating rami to coresponding spinal nerves
2. vascular branches – surround the aorta - aortic plexus
3. cardiac thoracic nerves
4. splanchnic nerves – these contain preganglionic fibres!!
- greater splanchnic n. (6th - 9th ganglia) terminate in the coeliac ganglion
-lesser splanchnic n. (10th and 11th ganglia) terminate in the aorticorenal ganglion
Lumbar part
contains 4 lumbar ganglia (in the retroperitoneal space on sides of lumbar vertebrae)
receive - white communicating rami from L1-3 spinal nerves
send:
l. grey communicating rami to the lumbar spinal nerves
2. vascular branches – surround the aorta - aortic plexus
3. lumbar splanchnic nerves (contain preganglionic fibres mainly) → enter aortic plexus
enter coeliac plexus and terminate in coeliac ganglia
enter renal plexus and terminate in aorticorenal ganglia
enter superior and inferior mesenteric plexuses and terminate in
the sup. and inf. mesenteric ganglia
all postganglionic fibres take part in
the superior hypogastric plexus which descends into the lesser pelvis as hypogastric nerves
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Pelvic part
contains 4 - 5 sacral ganglia lying in front of sacrum
receive preganglionic fibres from L1-3 spinal nerves via interganglionic fibres
send:
l.grey communicating rami to sacral and coccygeal nerves
2. branches joining with superior hypogastric nerves to form
inferior hypogastric plexus = pelvic plexus - gives
- inferior and middle rectal plexus
- vesical plexus
- uterovaginal plexus / defferential plexus
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