00:01
So now let's turn our attention
to the autonomic innovation
of the rectum and the anal canal.
00:06
So here we have the muscle
layer of the rectum.
00:09
We have the internal anal sphincter,
and we can see that both of these
are going to be innovated
by the inferior hypogastric plexus.
00:17
We see there's also a contribution
from parasympathetic and
sympathetic in green and blue.
00:23
So let's do what we did
similar to the bladder.
00:26
With sympathetic innovation,
you're going to have relaxation of
the muscle layers within the rectum
to allow storage of feces
and we're going to have contraction
of the internal anal sphincter.
00:37
With parasympathetic
that is going to drive defecation,
you're going to have contraction
of the muscle layer of the rectum
and you're going to have relaxation
of the internal anal sphincter.
00:49
But also we have the
external anal sphincter
and this is under
somatic nervous control.
00:55
So similar function
to that of the bladder
by way of the
inferior rectal nerve,
the somatic nerve you're going
to be able to contract and relax
the external anal sphincter
depending on your urge
for defecation.
01:08
So parasympathetic
will drive defecation.
01:11
Sympathetic will allow
the storage of feces.
01:14
When you have the urge to defecate,
you're then in control of it via the
conscious contraction or relaxation
of the external anal sphincter
via the inferior rectal nerve
which is somatic in nature.
The lecture Autonomic Innervation of the Rectum and Anal Canal by James Pickering, PhD is from the course Lymphatics and Nerves of Abdominopelvic Region.
Which autonomic nerve plexus innervates the anus?
Which nerve is responsible for somatic control of the external anal sphincter?
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