In order for stomach to work,
it needs to have oxygen
to make the cells work, so they can respire,
create energy, so they can carry out their function.
And it also needs to have venous drainage
so we are going to look at the vasculature
of the stomach. And importantly you just
need to remember again, the lesser
curvature and the greater curvature,
running around the right
and the left borders of the stomach.
So we can see that if we
concentrate on the lesser curvature,
we have two what are known as the
gastric blood vessels.
The left and the right
gastric blood vessels.
These come either directly
or indirectly from an important
blood vessel knows as Coeliac Trunk.
And we'll cover this in later lectures
where we'll look holistically at all
of the blood vessels at once,
because it makes more sense that way. But
individually, running along the lesser curvature,
we finally have the left
gastric artery and we finally have
the right gastric artery. And these arteries
will form a complete circuit
along this lesser curvature
the two gastric arteries.
We can then see with this greater
curvature, we have two more
blood vessels. We have the left
gastro-omental and the right gastro-omental
and these are going to be
coming in this direction and this direction,
right and left
gastro-omental arteries and again these will
join to form a circuit around this
greater curvature. So how can you
remember your greater curvature and your lesser
curvature, vasculature or
gastric is a short word
short word gastric for the lesser curvature, the small
of the two curvature. Gastro-omental
is a longer word and that runs around
the longer, greater curvature.
You can also see we have
some short gastric blood vessels that
supply the fundus and these come off
the splenic artery, which we will see later on.
The venous drainage
mirrors the arterial supply.
So if you are happy
with the arterial supply and then just
convert the word "artery" to vein and you will have
gastric-vein and you will have gastro-omental vein.
These pass back to the liver via what’s
known as the portal system. And then again we'll cover
that in more detail. So this is the
vasculature of the stomach. We'll also need to
look at how the stomach activity is
controlled and to do that we'll look at the
nerve supply. I am sure some of
you are familiar with the autonomic
nervous system. This is the part of nervous system
that we are not consciously in
control of, not like the somatic
nervous system which controls the skeletal
muscles that allows me to contract the biceps.
The autonomic nervous
system is ticking over all of the time.
And we can see here in purple
and in green, we have two different
parts of it, we have
parasympathetic and the sympathetic.
And now for the stomach
its activity is controlled by
the autonomic innervation.
And increases of it activity are controlled via the
parasympathetic nervous system,
this increases activity. This will increase
the rate of peristalsis,
increase the production of acid,
the release of pepsinogen.
And it's controlled
by the main parasympathetic nerve of the body,
the Vagus Nerve. This enters
into the abdomen; the vagus nerve
starts high up in the neck at the
base of the brain from the region called
the medulla and it passes down the
thorax enters the abdomen via the
oesophageal hiatus and then it
spreads over the surface of the stomach.
It also gives branches to what’s known as Coeliac Plexus.
And we'll cover that in a later
class because that controls other
parts of the abdominal viscera.
So this vagus nerve controls the activity of
the stomach. It really increases the activity,
once you had dinner,
you sit down in your lounge or
do any kind of activity, the digestion
of the food is controlled by the
parasympathetic via the vagus nerve.
If you are on an activity to go down,
if you do an activity that don't
really require your stomach to work that heavy,
that's why the sympathetic
division, okay? The sympathetic division of
autonomic nervous system dumping
down the activity
of the stomach.
And this is why the
nerve called the
greater splanchnic nerve.
And we'll look at the
splanchnic nerves again in the
greater detail when we'll
cover the nerve supply
which we can see here.
The autonomic nerves are
going to be covered in more
detail in lecture 20, so don't
worry too much right now.
If you are not quite fully comfortable with
these, we'll go over in great
detail in our last lecture of this