Now, for the reproductive
organs, for erection,
emission and ejaculation, it
is slightly more complicated.
The same principles exist.
We have our superior hypogastric plexus.
We have our hypogastric nerves.
We have the inferior hypogastric plexus.
But the actual process of erection,
emission and ejaculation
use both parasympathetic
and sympathetic. So for
an erection to occur
that is mostly down to
a parasympathetic input.
So for an erection to occur,
the smooth muscle of
the erectile tissues relaxes
and this allow blood to
fill the erectile tissues.
So with parasympathetic input
via the prostatic plexus.
So erection can occur while the smooth
muscles of the erectile tissue relaxing
allowing the blood to fill these spaces.
Now for emission to occur,
that's when the semen and the sperm
are delivered to the prostatic urethra
as a sympathetic response.
So a sympathetic response allows the sperm
to pass along the vas deferens and
enter into the prostatic urethra.
And that's emission. We can see
that's happening via say the testicular
plexus which we can see here.
So we have multiple systems,
multiple plexuses going on
that enable both the erection
to emission to occur.
For ejaculation where
semen is expelled
through the external urethral orifice.
Then that uses sympathetic
input. That's important
because it closes off the internal
urethral sphincter. If it didn't
then semen could pass into the bladder.
We know closure of the internal urethral
sphincter is a sympathetic response.
So it utilizes that pathway.
And also, for the ejaculation to actually occur,
we need to contract the bulbospongiosus muscle.
Because the bulbospongiosus muscle is surrounding
the corpus spongiosum. It's surrounding the
urethra that now has the sperm in.
And contraction of this muscle
squeezes the urethra and it ejaculates
the semen. So we see that for
erection, emission and ejaculation,
it's a whole process that involves
both somatic and autonomic
systems, complicated process.
For the uterus and the vagina,
we can return to our
typical superior hypogastric plexus,
inferior hypogastric plexus and our
hypogastric nerves that communicate
between the two.
And we can see for
the uterovaginal plexus
this runs alongside the uterine artery.
And really it's an extension of
the inferior hypogastric plexus.
So we can see we have got the
inferior hypogastric plexus here
and then running alongside
the uterine artery,
we can see we have got
the uterovaginal pelxus.
That's going to have inputs from the
sympathetic nervous system, so
coming from the lumbar
regions that pass into the
inferior mesenteric plexus,
then drop down via the
superior hypogastric plexus
and the hypogastric nerves.
And we can see the inferior
hypogastric plexus also has the
pelvic splanchnic nerves
passing from S2-S4.
So we can see that we have
a whole series of these
autonomic nerves supplying
the organs within the pelvic.