The enteric nervous system (ENS) is composed of two plexuses - the myenteric plexus and submucosal plexus. The myenteric plexus controls gastrointestinal movements through motor neurons that innervate the outer longitudinal and inner circular muscle layers. The submucosal plexus controls local intestinal secretion, absorption, and submucosal muscle contraction through mainly excitatory neurons. Together the ENS can function independently of the autonomic nervous system to regulate peristalsis and secretory functions through a network of sensory neurons, interneurons, and motor neurons.

1. By
Dr. Indusree. C. Suseelan
3rd yr PG
Dept. of Shareera Rachana,
Sri Dharmastala Manjunatheswara college of Ayurveda,
udupi 12017 dr indusree c suseelan

2. 2
Peripheral nervous system by J.N Langley
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4. Enteric nervous system
• Confined within the wall of the GUT
• Extends from oral part of the Esophagus to
the Internal anal sphincter.
• 2 sets of intercommunicating nerve plexus
– MYENTERIC / AUERBACH plexus
– SUBMUCOUS / MESSINER plexus
Both plexus are composed of intricate
network of fine un-myelinated nerve fibers
intermingled with clusters of neuronal cell
bodies arranged in the form of ganglia
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5. MYENTERIC PLEXUS
• AUERBACH’s plexus
• Located b/w the outer longitudinal and the inner
circular layers of smooth muscles extend from the
upper esophagus to the anus.
• Multipolar
• Motor function
• Controls mainly the gastrointestinal movements
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6. SUBMUCOSAL PLEXUS
• MEISSNER’s plexus
• Lies b/w the inner circular smooth muscle and the
muscularis mucosae and runs from the stomach to the
anus.
• Bipolar/ unipolar  Sensory function
• Multipolar  interneurons.
• Controls mainly gastrointestinal secretions & local blood
flow
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8. Secretory
functions
Can even function
Without the
participation of ANS
**
Peristaltic
movements
ENS works independently to
maintain
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9. Equivalent to
total no: of
neurons in
spinal cord
Derived
from
specific
area of
neural crest
cells
10-100
million
neurons
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10. Supported
by astrocyte
like glial
cells
BLOOD –
GANGLION
BARRIER
No
endoneurium
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11. Sensory
neurons
Motor
neurons
interneurons
3 types of functional neurons:-
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12. Sensory neurons
• Bipolar / unipolar neurons
• Confined in the Sub-mucous plexus
• Activated by- distension of gut wall- stretch receptors
• Receive chemical stimulation from mucosa- chemical
receptors
• Axons synapses with interneurons located close to the
circular muscle layer.
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14. interneurons
• Their axons are projected longitudinally
up & down to a series of motor neurons
which are located mostly in the
myenteric plexus & some in submucosal
plexus
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15. Motor neurons
EXCITATORY
*Acetylcholine
(Ach)
*Substance-P (SP)
INHIBITORY
*adenosine triposphate
(ATP)
*vasoactive intestinal
polypeptide(VIP)
*Nitric oxide (NO)
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17. Motor neurons project fibers
o Smooth muscle fibers of outer longitudinal and inner circular
layers,
o muscularis mucosae,
o glands &
o blood vessels of the gut.
Some fibers projected outside the gut
o to the ANS for modulation of the neural output &
o to the mesenteric blood vessels for regulation of the blood
flow.
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Gastro-intestinal reflex pathway
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20. MYENTERIC PLEXUS
• Controlling muscle activity
along the length of the gut with
specific effects:-
– Increased muscle tone
– Increased intensity of the
rhythmical contractions
– Slightly increased rate of the
rhythm of contraction
– Increased velocity of
conduction of excitatory
waves along gut wall, causing
more rapid movement of gut
peristaltic waves
• Composed of excitatory as
well as inhibitory neurons
SUB-MUCOSAL PLEXUS
• Controlling function within the
inner wall of each minute segment
of intestine such as:-
– Local intestinal secretion
– Local absorption
– Local contraction of sub-
mucosal muscle
That causes various degrees of in-
folding of G I mucosa.
• Composed of mainly excitatory
neurons
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21. Applied anatomy:-
• Injury to the ENS neurons or its pathway
may leaded to chances of slow recovery
due to absence of endoneurium
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