1. Lecture: 11 Dr. Eyad M. Hussein
Anatomy and Physiology of Parasympathetic Nervous System
Dr. Eyad M. Hussein
Ph.D of Neurology
Consultant in Neurology Department,
Nasser Hospital,
Assistant Professor,
Faculty of Medicine, Islamic University
Faculty of Dentistry, University of Palestine

2. الرجاء تحويل الجوال إلى وضع الصامت مع الشكر
الرجاء تحويل الجوال إلى وضع الصامت مع الشكر

3. (Involuntary Nervous System or Visceral Nervous System)
Anatomy of the Autonomic Nervous System
(Involuntary Nervous System or Visceral Nervous System)
Definition: it is the involuntary nervous system which supplies:
Unstriated (smooth) muscles of the viscera and blood vessels.
Cardiac muscles.
Glands.

5. Structures of the Autonomic Nervous System
Sympathetic nervous system (Thoraco-lumbar).
Parasympathetic nervous system (Cranio-sacral).

6. Parts of the Autonomic Nervous System
Central part: consists of autonomic nuclei in the brain stem, thalamus, hypothalamus and insula.
Peripheral part: consists of:
Sympathetic nervous system (SNS).
Parasympathetic nervous system (PSNS).

7. The Origin of the Autonomic Nervous System
The origin of the sympathetic nervous system:
Consists of fibers which arise from the 12 thoracic and upper 2 lumbar segments (Thoraco-lumbar part) and reach the sympathetic chain by the white rami.
2. The Origin of the Parasympathetic Nervous System:
a. The cranial part: consists of fibers which pass in
four cranial nerves (3, 7, 9 & 10 cranial nerves)=10973
b. The sacral part: consists of fibers which arise
from the S2, S3, and S4 segments of the spinal cord.

8. The Peripheral Autonomic Nervous System
Most of the visceral structures are supplied by two
systems (receive sympathetic and parasympathetic nerves).
The SNS supplies:
Skin of the body (its arterioles, sweat glands).
Blood vessels of the limbs (its smooth muscles).
Deep viscera.
The PSNS supplies the deep viscera only.
Each of the two systems consists of two order neurons.

9. 1. First Order Neurone It is formed by:
The nerve cells of certain nuclei in the brain stem.
Lateral horn cells (intermediolateral nuclei) of the spinal cord: D1-L2 and and AHCs of S2-S4.
The axons of these cells carry stimuli to the autonomic ganglia (called preganglionic fibers which are myelinated).

10. 2. Second Order Neurone
It is formed by the nerve cells in the sympathetic
and parasympathetic ganglia.
The axons of these cells carry stimuli to the
viscera (called postganglionic fibers which are
non-myelinated)

11. Types of Autonomic Ganglia
They are present outside the CNS and may be:
Paravertebral ganglion (Sympathetic): as sympathetic trunk (chain).
Collateral ganglia (Peripheral or Sympathetic): as celiac, superior mesenteric and inferior mesenteric ganglia.
Terminal ganglia (Parasympathetic): they are present on the walls of the viscera.

12. Notice that:
The sympathetic preganglionic fibers are short, while the postganglionic fibers are long.
The parasympathetic preganglionic fibers are long.
while the postganglionic fibers are short.
The preganglionic fibers are myelinated.
The postganglionic fibers are non-myelinated.

14. Transmitters of the Autonomic Nervous System
1. The preganglionic transmitter:
For sympathetic and parasympathetic preganglionic
transmitter is Acetylcholine.
2. The postganglionic transmitter:
a. All postganglionic fibers of the parasympathetic are
Acetylcholine.
b. The majority of sympathetic postganglionic fibers are
Epinephrine and Norepinephrine. The few which
are known to be Acetylcholine (for the sweat glands and
some cutaneous and skeletal muscle blood vessels).

16. How are the Visceral Structures Supplied by Autonomic (Motor) Fibers?
The autonomic supply to the visceral structures in two points:
Most of the visceral structures have two nerve supply: one sympathetic and one parasympathetic. One of these nerves acts "stimulator" while the other acts "inhibitor".
Each of two motor nerves (sympathetic and parasympathetic) is formed of a chain of two neurons:
a. The body of the first neuron is found in the CNS
and its axon is called a preganglionic fiber.
b. The body of the second neuron is found in the
PNS and its axon is called a postganglionic
fiber.

17. The Parasympathetic Nervous System
Cranio-Sacral System
The parasympathetic NS consists of two parts:
The cranial part: in nuclei of 3, 7, 9 & 10 cranial nerves in brain stem) =
The sacral part: it formd by the cells of intermediolateral nucleus in the anterior horns of S2, 3, 4 segments of the spinal cord.

19. A. The Cranial Part of the PSNS 1. Oculomotor Nerve (III)
First order neuron: Edinger-Westphal nucleus in midbrain.
Second order neuron: Ciliary ganglion.
Preganglionic fibers: the axons of the Edinger-Westphal
nucleus pass in the oculomotor nerve (nerve to inferior
oblique muscle) and relay in ciliary ganglion.
Postganglionic fibers: the axons of the ciliary ganglion
give short ciliary nerves which supply the sphincter
pupillae and ciliary muscles.

21. 2. Facial Nerve (VII)
First order neuron: superior salivary nucleus in the pons.
Fibers: the axons of these cells pass in the facial nerve then
run in two branches of facial nerve:
1. Preganglionic fibers (Greater petrosal nerve): which
relays in pterygopalatine ganglion (second order neuron).
Postganglionic fibers: from this ganglion to the
lacrimal gland, and glands of the nose , palate and
pharynx.
2. Preganglionic fibers (Chorda tymbani ): which relays in
sbmandibular ganglion (second order neuron).
Postganglionic fibers: arise from the ganglion to
supply the submandibular and sublingual salivary
glands.

24. 3. Glossopharyngeal Nerve (IX)
First order neuron: Inferior salivary nucleus in the
medulla oblongata.
Second order neuron: Otic ganglion.
Preganglionic fibers: the axons of the inferior salivary
pass in the lesser petrosal nerve and relay in otic
ganglion.
Postganglionic fibers: the axons of the otic ganglion
join with the auriculotemporal nerve to supply the
parotid gland.

26. 4. Vagus Nerve (X)
First order neuron: dorsal nucleus of vagus in the medulla
oblongata.
Preganglionic fibers: are formed by the axons of these cells
which pass in the vagus nerve (relay in many ganglion in
different organs in the thorax and abdomen).
Postganglionic fibers: the axons of the terminal ganglia in
the different thoracic and abdominal organs pass directly to
supply:
Heart, bronchi, lung, liver, pancreas, kidneys, esophagus,
stomach, small intestine, and large intestine (up two
junction of right 2/3 and left 1/3 of transverse colon), liver,
pancreas, kidneys.

27. B. The Sacral Part of the PSNS
First order Neuron: are formed by the cells of the
intermediolateral nucleus of the anterior horn of the
S2, S3 & S4 segments of the spinal cord.
Preganglionic fibers: are formed by the axons of the
cells in the lateral horn of S2, S3 & S4 segments of the
spinal cord → ventral rami of S2, S3 & S4 spinal nerves
→ pelvic splanchnic (nervus erigens), which pass
directly to synapse with the terminal ganglia present on
or in walls of the pelvic viscera.

28. Postganglionic fibers: arise from the cells of these terminal
ganglia to supply:
1. Left 1/3 of the transverse colon, descending colon, pelvic
colon, and rectum.
2. Urinary bladder:
The muscles of its wall.
Internal sphincter (smooth muscle fibers).
3. Genital organs.
The pelvic parasympathetic system is concerned with emptying of the urinary bladder and rectum.

29. The Parasympathetic Ganglia in the Head and Neck
There are four parasympathetic ganglia in the head and neck:
Ciliary ganglion.
Submandibular ganglion.
Sphenopalatine (pterygopalatine) ganglion.
Otic ganglion.

31. Ciliary Ganglion
Type: it is a small parasympathetic ganglion (1-2 mm in diameter).
Site: in the posterior part of the orbit.
Roots Entering the Ciliary Ganglion:
Sensory root: branch from nasociliary nerve.
Sympathetic root: from the internal carotid sympathetic plexus.
Parasympathetic root: from nerve to inferior oblique muscle (branch of oculomotor nerve).

32. Branches of the Ciliary Ganglion
The ciliary ganglion has 8-10 short ciliary nerves which pierce the sclera around optic nerve.
They contain:
Sympathetic fibers: to the blood vessels of the eye.
Sensory fibers: to the cornea and iris.
Parasympathetic fibers: to the supply the sphincter pupillae (for light reflex) and ciliary muscle (for accommodation).

38. Submandibular Ganglion
Type: it is a small parasympathetic ganglion (2-3 mm in diameter).
Site: it lies in the submandibular region on the upper part of hyoglossus muscle.
Relations:
Superiorly: lingual nerve.
Inferiorly: deep part of submandibular gland and its duct.
Medially: hyoglossus muscle.
Laterally: mylohyoid muscle.

41. Roots Entering the Submandibular Ganglion
Parasympathetic root: arising from the chorda tympani nerve. It joins the lingual nerve then the parasympathetic fibers leave lingual nerve to relay in the ganglion.
Sympathetic root: arising from the plexus around facial artery.
Sensory root: from lingual nerve (branch of mandibular nerve).

42. Branches of the Submandibular Ganglion
Several small branches (mixed: parasympathetic + sympathetic + sensory fibers) pass directly from the ganglion to supply the submandibular salivary gland.
Similar branches join the lingual nerve to reach the sublingual salivary gland.

44. Sphenopalatine (Pterygopalatine) Ganglion
Type: it is the largest parasympathetic ganglion (4-5 mm in diameter).
Site: it lies in the pterygopalatine fossa.
Roots Entering the Sphenopalatine Ganglion:
Sensory root: two sensory branches arising from the maxillary nerve.
Sympathetic root: the deep petrosal nerve from sympathetic plexus around the internal carotid artery.
Parasympathetic root: the greater petrosal nerve from facial nerve.

47. Branches of the Sphenopalatine Ganglion
Orbital branches: enter the orbit through the inferior orbital fissure. They supply the orbital periosteum and the mucous membrane of the sphenoid air sinus. Another fibers pass with the zygomaticotemporal nerve to the orbit, where they branch off to join the lacrimal nerve to supplies lacrimal gland.
Pharyngeal branch: to supply the mucous membrane of the nasopharynx.
Greater palatine nerve: to supply the mucous membrane of the hard palate and part of the nose.
Lesser palatine nerve: to supply the mucous membrane of the soft palate and the palatine tonsil.
Short sphenopalatine nerve: to supply the mucous membrane of the upper part of the lateral wall of the nose and nasal septum.
Long sphenopalatine nerve: to supply the mucous membrane of the anterior part of the hard palate.

53. Otic Ganglion Type: it is a small parasympathetic ganglion.
Site: in the infratemporal fossa just below foramen ovale.
Roots Entering the Otic Ganglion:
Motor root: arising from nerve to medial pterygoid muscle.
Parasympathetic root: formed by lesser superfacial petrosal nerve which carries preganglionic parasympathetic fibers from tympanic branch of glossopharyngeal nerve.
Sympathetic root: from the plexus around middle meningeal artery.

56. Branches of the Otic Ganglion
Motor branch: to tensor palati muscle and another branch to tensor tympani muscle.
A communicating branch: to auriculotemporal nerve, this branch is formed of:
a. Sympathetic fibers: to supply the blood vessels of parotid gland.
b. Parasympathetic fibers: secretomotor to parotid gland.

60. The Parasympathetic Ganglia in the Head and Neck
Ganglion
Nucleus
Parasympathetic root
Sensory root
Sympathetic root
Organs supplied
Ciliary
Edinger-Westphal
Oculomotor nerve
Nasociliary
Nasociliary nerve from internal carotid plexus
Sphincter pupillae and ciliary muscles
Sphenopalatine
Superior salivary
Greater superfacial petrosal nerve from VII nerve
Maxillary
Deep petrosal nerve from internal carotid plexus
Lacrimal glands; glands of nose, palate, mouth and pharynx
Submandibular
Chorda tympani nerve from VII nerve
Lingual
Plexus around facial artery
Submandibular and sublingual glands
Otic
Inferior salivary
Lesser superfacial petrosal nerve from IX nerve
Mandibular
“Motor “
Plexus around middle meningeal artery
Parotid gland
Many ganglion in the different organs
Dorsal motor nucleus of vagus
Vagus nerve
Many nerves
Many plexus
Heart, Respiratory system, Abd. viscera

62. Thank You