Transcript The Visceral Nervous System

Visceral Nervous
System
SHANDONG UNIVERSITY
Liu Zhiyu
The Visceral Nervous System
Composition
Visceral motor nerves (autonomic
nervous system
Sympathetic
part
Parasympathetic
part
Visceral sensory nerves
Visceral motor nerves
preganglionic
neuron
preganglionic
fiber
postganglionic postganglionic
fiber
neuron
The differences between somatic motor
and visceral motor n.
Somatic
Visceral
Effectors
Skeletal muscles Cardiac, smooth muscles and
glands
Kind of fibers
One
Two: sympathetic and
parasympathetic
From lower
center to
effector
Single neuron
Two neurons:
preganglionic neuron (fiber)
postganglionic neuron (fiber)
Fibers
Thick myelinated
Preganglionic: thin myelinated
postganglionic: unmyelinated
Distributive
form
Nerve trunk
Nerve plexuses
Control
Voluntary
Involuntary (unconsciousness )
(consciousness)
Sympathetic part
 Lower center located in
lateral horn of gray mater of
spinal cord in segments
T1~L3

The peripheral part
of sympathatic part

Sympathetic ganglia
Prevertebral ganglia
Paravertebral ganglia
Paravertebral ganglia
Position:
Arranged on either side of
vertebral column
Number:
Consist of 19~22 ganglia





cervical ganglia ：3
thoracic ganglia： 10~12
lumbar ganglia： 4
sacral ganglia： 2~3
Coccygeal ganglion
（Ganglion impar ） 1
unpaired on the anterior face of
coccyx
Superior
cervical
ganglion
Middle
cervical
ganglion
inferior
cervical
ganglion
 Sympathetic trunk
Formation:
It is formed by paravertebral
ganglia and interganglionic
branches
Position:

lie on either side of
vertebral column from base
of skull to coccyx

The trunks of two side
unite at the ganglion impar in
front of the coccyx
Prevertebral ganglia

Lie anterior to vertebral
column and near the arteries
Celiac ganglion
Aorticorenal ganglion
Superior mesenteric
ganglion
Inferior mesenteric
ganglion
The communicating branches
White communicating branches
•
preganglionic fibers
（myelinated） sent out by the
nurons of the lateral horn;
• 15 pairs in number (T1—L3)
Gray communicating
branches
• postganglionic unmyelinated
fibers sent by the neurons of
paravertebral ganglia,
• 31 pairs in number.
preganglionic fibers
They pass to sympathatic trunk
via white communicating
branches and terminate in 3 ways:

Some fibers synapse with
neurons in the corresponding
paravertebral ganglion;
 Some fibers pass up or down
in sympathatic trunkbefore
terminating in the
paravertebral ganglion;
The
others pass through the
paravertebral ganglion and
terminate in prevertebral
ganglion via the splanchnic n.
postganglionic fibers
They also terminate in 3
ways:

Some fibers pass
through the gray
communicating branches
to spinal n. and to the
peripheral blood
vessels,sweat gland and
arrectores pilorum;
postganglionic fibers
surrounding
the artery
as a layer of nervous
plexus to innervate the
corresponding organs;

terminating directly in
the certain organs
The general distribution
of sympathatic nerve
The cervical part of
sympathatic trunk
The
postganglionic fibers pass
through the gray
communicating branches to 8
cervical nerves and distribute
the head, neck and upper
limb(blood vessels, sweat gland
and arrector pilorum);
The
fibers surround the
internal and external carotid
arteries to innervate the glands
of the head and neck, the dilator
pupillae;
The general distribution
of sympathatic nerve
The cervical part of
sympathatic trunk

Send out cardiac branches to
heart (to form the cardiac plexus
with cardiac branch of vagus n.)
send out pharyngeal branch to
the pharynx
The thoracic part of
sympathatic trunk
Greater
splanchnic nerve
formed by preganglionic fibers
from T5~T9 ganglia, and relay in
celiac ganglion.
Lesser
splanchnic nerve
formed by preganglionic fibers
from T10~T12 ganglia, and relay
in aorticorenal ganglion.
The thoracic part of
sympathatic trunk

The postganglionic
fibers supply the liver,
spleen, kidney and
alimentary tract as far
as the left colic flexure.
Lumbar
splanchnic nerve
Formed by preganglionic fibers from
L1~L4 ganglia, and relay in
prevertebral ganglia.

The postganglionic fibers supply
descending and sigmoid colon,
rectum, pelvic viscera and lower
limbs.
Distribution of sympathetic nerve
Preganglionic fibers
T1~T5
T5~T12
L1~L3
Postganglionic fibers
Head, neck, upper limb and
thoracic viscera
Abdominal viscera
Pelvic viscera and lower limb
Parasympathetic par
Lower center :
four pairs
parasympathetic nuclei in
brain stem
in sacral parasympathetic
nucleus of spinal cord in
segments S2~S4
Parasympathetic part
Parasympathetic ganglia:

terminal ganglia are near or within the wall of a visceral
organ
–Para-organ ganglia ：

Ciliary ganglion

Pterygopalatine ganglion

Submandibular ganglion

Otic ganglion
–Intramural ganglia
Cranial portion
Ⅲ
accessory
oculomotor
nucleus
superior
salivatory
nucleus
ciliary ganglion
〈○
Ⅶ
sphincter pupillae
and ciliary mscles
pterygopalati
ne ganglion
〈○
〈○
Submandibular
ganglion
lacrimal gland
submandibular
gland
Sublingual gland
Cranial portion
inferior
salivatory
nucleus
dorsal
nucleus of
vagus n
Ⅸ
〈○
parotid gland
otic ganglion
Ⅹ
〈○
terminal ganglia
heart, lungs,
liver, spleen,
kidneys,alimen
-tary tract as
far as left colic
flexure
Sacral portion
sacral
parasympathetic
nucleus
Sacral n.
S2-S4
Pelvic plexus
Postganglionic
fibers
Pelvic
splanchnic n.
Synapse with
terminal
ganglia
supply the
descending and
sigmoid colon, rectum
and pelvic viscera
Main differences between sympathetic and
parasympathetic
Sympathetic
Parasympathetic
Lower center
Lateral gray horn of
spinal cord segments
T1~L3
Four pairs parasympathetic
nuclei and sacral
parasympathetic nucleus
Ganglia
Paravertebral,
prevertebral
Terminal
Preganglionic f.
Shorter
Longer
Postganglionic f.
Longer
Shorter
Pre:
Postganglionic
1: many more
1: a few
Distributions
Throughout the body
Limited primarily to head
and viscera of thorax,
abdomen, and pelvis
Different action
Prepares for emergency
situation (fight or flight)
Conserve and restore body
energy (rest and relaxation)
Visceral plexuses
Cardiac plexuses
- Superficial , below aortic arch
- Deep, anterior to
bifurcation on trachea

Pulmonary plexus

Celiac plexus

Abdominal aortic plexus


Hypogastric plexus
Superior hypogastric plexus
Inferior hypogastric plexus
(pelvic plexus)
Referred pain
Ciliary ganglion
Pterygopalatine
ganglion
Submandibular
ganglion
Otic ganglion
Main differences between sympathetic
and parasympathetic