00:01
In this topic, we're going to have
a look at the lymphatic system
across the abdominopelvic region.
00:07
So, let's first of all
just remind ourselves
of some basic principles
of the lymphatic system.
00:13
So, here we can see
the left side of the heart,
which is very much
giving rise to arteries
that go to supply various organs
with oxygenated blood
via the various capillaries.
00:23
That blood is then going to pass
through the organs
via capillaries
and returned to the right side of
the heart via the venous system.
00:31
As a consequence of this
activity at the cellular level,
there's often some excess fluid
that also needs to be drained away.
00:40
And this is done via
the lymphatic system.
00:42
Primarily associated
with the organs,
we have a number
of lymphatic vessels,
and these will
pass through lymph nodes,
as they then ultimately go towards
the right side of the heart
like series of collecting ducts,
which we'll come to
in a moment or so.
00:57
So, there's a series
of tubes really.
01:00
Some associated taking oxygenated
blood and nutrients to organs.
01:05
Others then taking that
venous blood back to the heart
or elsewhere for
it to be replenished.
01:12
But there's also
another set of tubes.
01:14
These lymphatic vessels
that form the lymphatic system
that helped to take some
of the extracellular fluid
back towards the heart
so it can enter
into the circulatory system.
01:25
So, let's have a look
at a typical lymph node,
which is going to receive these
afferent lymphatic vessels.
01:32
So, these afferent
lymphatic vessels
are going to arrive
at the lymph node.
01:36
They're going to pass through
the lymph node,
and they're going to leave via
these efferent lymphatic vessels.
01:43
Here if we look at a lymph node,
we can see it's surrounded
by a capsule.
01:47
And there's various segments
within this node,
which are demarcated
by these trabecular.
01:52
We can see inside the node
there is a cortex
and an inner medulla.
01:57
And these helps a lymph node
to carry out its function.
02:00
Partly starting to filter some of
this fluid that's passing into them.
02:05
So with that basic structure,
let's just have a look
at some of the flow
of how the lymph moves through
the various lymph nodes.
02:12
So, here we can see the
afferent lymphatic vessels
is taking the lymphatic
fluid towards the lymph node,
and then it passes to
some subcapsular sinus here.
02:21
We also have an intermediary sinus
that allows the lymphatic fluid
to pass through the node
and allowing the
filtering process to occur.
02:29
We're going to see enters
into this medullary sinus
before it passes out via
an efferent lymphatic vessel.
02:36
And there's always fewer
efferent lymphatic vessels
leaving the lymph node
than there are afferent vessels
entering into it.
02:43
So here let's have a look at
the general overview
of the lymphatic system
within the body.
02:49
So, it's intimately associated
with the venous system
because that's
how the lymphatic fluid
can then pass towards the
right side of the heart.
02:57
Here we have the
left internal jugular vein
and the left subclavian
vein indicated.
03:02
And this is important
because the thoracic duct
passes into the connection between
these two venous structures.
03:09
On the right hand side we have
a slightly different pattern.
03:12
Here we have the
right internal jugular vein
and the right subclavian vein.
03:17
And here we have the
right lymphatic duct that passes.
03:20
But actually if we were
to look outwards,
we can see the
distribution and the map
of lymphatic drainage
is quite different.
03:28
The thoracic duct which
I indicated previously
takes the lymph fluid from
the vast majority of the body
except this upper right quadrant.
03:38
The upper right quadrant is served
just by the right lymphatic duct.
03:42
The thoracic duct
will receive the lymph
from the rest of the body,
so the lower half of the body
and the upper left quadrant.