Let's just now turn our attention to
the suprarenal glands and their anatomy.
Well, they have a cortex and
they have an inner medulla.
We can see that each of the suprarenal glands is going to
be positioned on the kind of superomedial aspect of the kidneys.
And they are surrounded by a substantial
amount of the perinephric fats
and the renal fascia, but they are separated from the
kidneys by this fibrous tissue, so there is a separation.
The left suprarenal gland
is triangular in shape
It's in contact with the
IVC medially and the liver
is laterally found. The right
suprarenal gland is more semilunar
in shape, is related to the stomach
spleen and the pancreas.
Two parts of the suprarenal glands and
they have different embryological origins
The outer cortex releases
corticosteroids and androgens
This essentially causes the kidneys
to retain salt and water.
That's going to have the effect of
increase in the blood pressure.
The inner medulla is actually derived
from the sympathetic nervous system,
it was part of the sympathetic
nervous system as it was developed
and it releases adrenaline which
supports that fight or flight response.
So the inner medulla of the suprarenal
gland is really the extension of the
sympathetic nervous system, so its involved
in the fight or flight response.
The vasculature of the suprarenal
glands is complex.
And essentially there are about three
arteries that supply each
of the suprarenal glands.
It's a highly vascular organ because it's endocrine in
function, releasing hormones into the blood stream.
And in total there is
about 50 or 60 tiny branches
coming from these
three sources we have.
If here is our suprarenal gland, we can
see here on the superomedial aspect
of the kidney and here we can
see the aorta. We have three
suprarenal arteries: a superior,
a middle and an inferior.
The superior suprarenal artery comes from
what's known as the inferior phrenic artery.
The inferior phrenic artery is a paired
artery, a left and the right one.
One of those paired visceral branches giving
rise to superior suprarenal arteries.
That goes to supply part
of the diaphragm and body wall
Along it's path, it gives rise
to superior suprarenal arteries
that come down and supply
the suprarenal glands.
We also have middle suprarenal arteries and
these can come directly from the aorta.
So middle suprarenal arteries coming
directly from the aorta.
Sometimes, because the coeliac
trunk would be located around here
these arteries can also come from the coeliac
trunk. But the middle suprarenal artery
and then we have the renal artery which
we know about going towards the
kidneys. Along it's course, it can give rise
to the inferior suprarenal arteries.
And that ascends up towards
the suprarenal glands.
So they has these three main sources: superior,
middle and inferior
suprarenal arteries. And together these
will give a whole series of small branches.
total in 50-60 arteries indicating
it's function as an endocrine gland.
Venous drainage is a lot more straight forward
and is by the way of a large suprarenal veins.
And these can drain into
the IVC directly or
via the renal vein. So we can see the suprarenal
vein is draining into the renal vein here
which will go into the IVC and then up or it can
drain into the inferior vena cava itself.
So we can see the vaculature of
suprarenal gland is really complex.