Spleen (anatomy)

we will be looking at the anatomy of the

spleen alright so in previous weeks we

have been looking at the anatomy of the

abdomen now is the stuff between the

diaphragm and the stuff in the pelvis it

is kind of got very demanding stuff like

that so he looked at the small intestine

the large intestine liver and when we

look at the pancreas we saw in the

nestling or the tail of the pancreas

Nestle's in the spleen what do you guys

know about the spleen what would you

like to know about the spleen me if you

don't know well you don't know about the

spleen then you don't know you from the

Latin its perspective then we should

have a look at where the spleen is can

you see the screen please there you see

it where is the spleen what are the

structures in the abdomen and next to

the spleen because if we know that then

we have a better understanding of our

anatomy but also if you were to look at

an x-ray or transverse MRI or CT scan or

even a coronal MRI CT scan you can work

out where the spleen is in relation to

the other organs and not confused and

the spleen with the kidney even do that

with you let me talk about the structure

of the spring itself have you been

enjoying the recent histology it

certainly a little bit but like I always

say Anatomy is the whole thing is from

the cells up to the gross stuff that you

can see the only thing that's limiting

you from looking at the cells is the

artificial limitation of your eyes we

need to understand them ultra the the

little tiny ultrastructure

anatomy to be able to understand the

gross anatomy and how it all works right

you can't have one without the other we

can but less fun doesn't make as much

sense so we'll have a little look at the

structure of the spleen and that will

help us explain its function and then

once we understand its structure and its

function we can think about what goes

wrong with the spleen can't we and of

course one thing you might know about

the spleen is that people have their

spleens removed that's the splenectomy

why would you have your spleen removed

can you live without your spleen I guess

you can't live without your spleen if

people have this things we lose but if

you have you clean removes is then that

have an effect is that a problem is if

you know sure I'll say yes

long answer we'll find out later so I

don't know if you are new to these

videos or if you've seen them before if

you've watched this video 10 times

already now this instruction seems a bit

weird to you

but some people watch these videos a lot

for exams and stuff but um I've been

recording these videos about a year now

this is the Christmas break there is

nobody around I have all of the labs to

myself there's nobody else at that up

their lines for the lab or even off I

think the third years or the fourth

years third is probably have exams after

Christmas one over there kicking around

but they're more interested in clinical

methods stuff because they know their

Anatomy doing but I've been uploading so

my aim was I'm a teaching lecturer and I

like teaching

I like Anatomy so that kind of works

also like making things so I something

for some reason I wasn't bored I've

plenty to do but I thought I would set

myself a challenge of creating an

Anatomy video every week for as long as

I could really but in the first instance

for at least a year so I completed that

well than me so I try to make a video

every week and upload every week on an

anatomical topic and usually it's

whatever I've been teaching that week

because I've already prepared something

it's fresh in my head I found hopefully

an interesting and engaging way of

teaching it the way I would teach it to

a small group of students is gonna be

different the way I present it to you

because you are a camera and you don't

respond to what I say well not quickly

you can do in the comment but then it's

super slow in it but yeah so I've

noticed actually there as the number of

subscribers has been increasing recently

that's quite motivational that quote

that seems quite nice that seems like

people are actually finding this useful

and listening to what I do so maybe I

should keep doing it and making more of

them so if you if you haven't subscribed

and this waffling hasn't put you off

then maybe do a subscribe below because

to be honest it's not something I asked

for this is kind of just an extra thing

I do for some reason you know what I

think one of the reasons for do

this for recording this or thing is as

an anatomist we're very aware of our own

mortality right we work with bodies that

people have kindly donated to us to

examine for our own study and for

students to study so we can better

understand human anatomy and we can

train people who need to understand

human anatomy so they can use it

clinically and look after people and

stuff so you think you've become very

aware that you are this soft squishy

thing that could be gone at any time one

other thing me-me-me

talking to you is not a substitute for

you gain in the lab right if you're a

student of anatomy then hopefully you

have access to a lab maybe two cadavers

maybe two models or at least two

skeletons you don't study Anatomy by

people talking to you

what I do in these videos is I choose

what to talk about I pick things that

I'm not going to tell you everything

because you'll be swamped and you'll be

asleep in no time I'm gonna pick things

out I think you're useful and important

I'm trying to get everybody out here

some some some videos will be more

details or some videos will be less

details of your doing more general but

for you to study Anatomy for you to

really understand it you need to study

it you need to spend time reading the

textbooks looking at the models studying

Anatomy that's how you learn it you

don't learn it from people in videos

talking to you alright I ain't that good

okay have you found that a split yet you

can see it

there is that's it there so look it's

it's it's its lateral right it's on the

left side price if you've got your

mid-axillary to outline the middle of

your Xillia there's a line that goes

down here it's a little bit posterior

right so it's not quite in the middle

it's a little bit it's kind of lateral

but a little bit posterior of lateral if

that makes sense and can the ribs got

one two three four five six seven eight

nine ten eleven twelve the little diddy

guy in the muscle back there so that

there is nine ten oh nine ten eleven so

the spleen is it about the ribs of a

level of ribs nine ten and eleven hey do

you know you can find your 11th rib

right so you've got you you got yeah

your costal cartilage right you got your

costal margin if you follow it round oh

why you find a cut laughs very sensitive

pokey things right or that is the

anterior end of your 11th rib because

11th rib is a floating rib like that it

is what I'm talking about here there you

go see take the zone take the liver

right you can see the diaphragm right

here's the diaphragm around here now if

I take the stomach out now you can see

the spleen more clearly so the stomach

is anterior to the spleen and here we

see the pancreas so the pancreas is

retroperitoneal so it's behind the

peritoneum and the tail of the pancreas

is going up into the hilum of the spleen

and the blood vessels of the spleen are

following the pancreas up into the hilum

there now those that's the splenic

artery in the splenic vein supplying

blood to the spleen and they supply well

the splenic artery supplying blood to

the spleen and it's supplying blood to

the pancreas as it goes along

and then the splenic vein is draining

blood from the pancreas and the splenic

vein will then meet the inferior

mesenteric vein and then the splenic

vein the in theorem using Terra vein

will continue and then meet with a

superior mesenteric vein and then they

become the portal vein and they go to

the liver over there so the spleen

drains its blood to the liver like a


intestinal organ does but it's not a

gastrointestinal organ it is a secondary

lymphoid organ see here this is the

large bowel this is the transverse colon

this changing direction here yeah so

it's so that is the left colleague

flexure also gets called the splenic

flexure because it's next to the spleen

so the large intestine look is kind of

at the inferior pole here and you can

see the diaphragm is is posterior to the

spleen and lateral to the spleen ribs

nine ten and eleven lateral to the

spleen here three four five six seven

eight nine ten eleven yeah because of

course member they're going up a bit

right angling up and around take that

out you can see that there is the kidney

so the superior pole of the kidney is

nestling up into the screen the kidney

is posterior the left kidney in the

right kidney the spleen is lateral and

it's more anterior than the left kidney

don't mix much they do look similar and

also like the spleen is more superior

than the kidney so you can imagine if

you've got a section where you just got

a beer spleen you might think is a

kidney but it's it's not you know

transverse section here's the esophagus

coming in here there's the adrenal gland

the abdominal aorta is is here there's

the inferior vena cava the kidneys are

retroperitoneal so they're posterior to

the peritoneum if you still haven't got

the hang of peritoneum peritoneal cavity

median trees yet go and look at my cling

film and peritoneum video and see if

that helps but we've talked about the

embryology so embryologically the

stomach starts off as a simple tube

right so in the embryo there's this

abdominal abdominopelvic or this there's

a cavity right in the EM in the embryo

and the early gut tube runs through that

cavity and it's held on to the posterior

abdominal wall by by two layers of meat

by two layers apparently in this serous

membrane two layers come together and

surround the

the early to band where they come

together forms the Me's entry where it

covers the tudors visceral peritoneum

where it lines the abdominal cavity

that's pralaya the peritoneum right now

at the level of the stomach we call we

ask to what we find a posterior Me's

entry in the embryos we call that the

the dorsal music Astrium we like to use

worth dorsal eventual we're talking

about embryos because it kind of curves

and folders and stuff mezzo so Me's

intrigued astrium gaster meaning you

know referring to the stomach in this

case but there's also a ventral mezzo

gas trium so there's a sheet of that

that means a gas stream between the

stomach and knee and the anterior

abdominal wall just at the level of the

stomach and then we saw that the the

liver develops in that ventral music

astrium so does part of the pancreas so

does the gall bladder

but in this dorsal music after another

bit of the pancreas forms but that's

where we also find the spleen forming

within those two sheaths those two

layers of dorsal music astrum between

the abdominal wall and the stomach now

the stuff that forms all lines the tube

of the GI tract comes from endoderm the

end of the layer of the three germ

layers of the embryo right so the liver

and the pancreas the gallbladder they're

all birds of endoderm from the GI tract

record not the spleen although it's in

the abdomen although it's in the Me's

entry it does not form from the


it forms from the amazing kind the Me's

adam land and everything else forms from

okay but this means that in the end all

then we we have the livers attached to

the anterior abdominal wall by the

falciform ligament that's part eventual

muse entry and then the liver is

attached to the stomach by the lesser

omentum that's part of the ventral music

astrium but then the stomach has this

this greater omentum hanging down from

it which kind of grows from the greater

immense and then back in attaches to the

top of the transverse colon but that

that then goes back that the stomach is

attached to the spleen

by the gastro splenic ligament it's not

really a ligament but you know it's

created tissue see they get called

ligaments the gastric splenic ligament

then joins the stomach and the spleen

and then because that's part of the

dorsal music Astrium and then the spleen

is attached to the posterior abdominal

wall kind of around the area of the left

kidney by the LIA no renal ligament

sorry I didn't name Leon Oh Latin for

spleen so that the Me's entry between

the spleen and the left kidney kidney

renal gets called the delaying of renal

ligament why didn't they call it the

splenorenal ligament maybe it does also

get caused the splenorenal ligament to

be fair the ligament or the the she of

Me's entry between the spleen and the

stomach does get called the gastro

lyonnel ligament see Anatomy you don't

just learn one word for a structure you

learn two more you've gotta spend time

on this stuff and then it becomes

language and it becomes easy and you

just remember in this fight so that

means that if the spleen is held in

place by those sheets of recently the

spleen is a little bit mobile and that

does make sense really because of course

is under the diaphragm diaphragm moves

everything else has to move a little bit

as well okay so that's where the spleen

is that's its blood supply those are the

organs nearby those are the connective

tissues holding in place in terms of

nervous innovation it has autonomic

nervous innovation and you got this idea

awesome so everything around here all

the parasympathetic innervation comes

from the vagus nerve and all the

sympathetic innervation has come from

the sympathetic trunk now we find around

these anterior branches from the

abdominal aorta say around the celiac

trunk here we find a celiac ganglion and

a celiac plexus so they could get

ganglion is the collection of cell

bodies where we have preganglionic

sympathetic neurons meeting

postganglionic sympathetic neurons

Andrew and the plexus is just where

these nerve fibers or these autonomic

nerve fibers are like crossing over

so we find this celiac plexus around

here and then sympathetic nerves and

Tori parasympathetic nervous to think

about is what but certainly sympathetic

nerves love to follow arteries to their

destination so we find autonomic nerves

around the celiac trunk so the the

fibers of the celiac plexus then follow

the celiac trunk and its branches in

this case the the splenic artery act of

the artery so they that was a really

long-winded way of saying that the

spleen is innervated by autonomic nerves

and the function of those Ottoman nerves

is vasomotor you know so sympathetic

innervation causes vasoconstriction as

we see elsewhere in the body

that's pretty cool though so I said that

the spleen is a secondary lymphoid organ

so we think about the immune system here

what are the primary lymphoid organs oh

marrow is the main one and also the

finest which is not that nice is up here

thymus is up here somewhere small

problem in children so the bone marrow

is the site of major site of

hematopoiesis in adults right there are

formation of new blood cells so

erythrocyte red blood cells and

lymphocytes B cells T cells are

something but of course T cells are so

named because precursor cells from the

bone marrow moved to the thymus and

mature in the thymus and then they

become T lymphocytes if an organ is

producing or significantly maturing

lymphocytes then it's a primary lymphoid

organs or bone marrow and thymus

secondary lymphoid organs are stores of

lymphoid cells or from lymphocytes so

then that tells us that the spleen is a

site where lymphocytes are stored and

yes we see T cells and B cells in here

and macrophages and all sorts but it's

also a place where we see a lot of

erythrocytes and platelets in the fetus

the spleen is also a site of

hematopoiesis so in in in the fetus the

spleen is making new blood cells

as is the liver in the in the fetus bath

to birth in humans at least it stops I

think in most mammals it doesn't do

hematopoiesis after birth being other

vertebrates it it might do don't think

it does in mammals anyway so in the

fetus hematopoiesis but after birth

it doesn't make red blood cells anymore

oh thinking about um development you

might find an accessory spleen I think

maybe like 10% of people might have a

little bit of accessory splenic tissue

you can imagine is going to be in that

that dorsal music astrium somewhere

right and something a bdd maybe a

centimeter or two in diameter useless

fact of the day anyway so if we look

inside the spleen we see red pulp and

white pulp so if we take a gross spleen

like a living spleen and we cut it in

half over number we'll see red areas and

white areas and now the spleen is

covered by a finish connective tissue

capsule and that capsule extends into

the spleen to give us some structure and

shape and as it extends in those are

trabecula that takes blood vessels into

the spleen and then we see most of those

blood vessels around those blood vessels

we see white pulp and in the white pulp

that's where we see our find our B cells

and our T cells and then outside of the

white PO pretty much everything else in

the spleen is red pulp because he looks

red and the reason he looks red is

because it's full of erythrocytes so the

spleen is a store of red blood cells and

it's also a store of platelets which

makes it very useful in trauma and blood

loss right because if you have bleeding

then you can release all bunch of

platelets and help stem that loss of

blooding Nia formed some clots and then

you've got red blood cells to replace

those that are lost the so it's kind of

a yeah I mean that's one of its

functions the immune system side them in

the white pulp this is a site of

opsonization which is not a word that

anatomist use very often it's a it's an

immunologist word

it's some so bacteria and foreign things

pathogens and bits get presented in the

spleen and then get tagged for

destruction that's optimization all

these that's now anatomist description

of optimization so it's um it's a site

where stuff that needs to be destroyed

gets targeted for destruction so is that

part of the immune response it's also a

site where antibodies can be produced

with a site where the body can mount an

immune response so that's the the white

pulp now the red pulp has also got

another funky function the body is

constantly producing erythrocytes red

blood cells and they don't hang around

forever they've got kind of a used boy

date and in the spleen you've got are

two arteries coming in and there are two

arterial blood goes into like sinusoids

and those sinusoids are lined with

endothelial cells like other blood

vessels but they've got an intra inter

inter endothelial slit and what happens

is that a RRIF red blood cells if you're

a nice happy young flexible red blood

cell of about the right size and

everything's good you'll just slip

through that sleaze going to squeeze a

little bit and you'll go through that

intra endothelial slit and you'll get

into the red pulp and you'll float

around you'll disappear off and you're

cool right but if you are an erythrocyte

that's that's in last for some reason

maybe some pathological process or maybe

you were just getting old and

everything's breaking down or if you've

got a bit stiff you're not really

flexible you can't really but get

through it anymore and maybe you break

up a little bit so if you're a weird

shape where you're not you're not very

deformable or you're a bit large you're

an erythrocyte that probably you know we

could do with recycling you're making

some more so those get sequestered by

the the spleen and then they get sent do

you remember how we got the the splenic

vein goes eventually to the portal vein

goes to the liver where those

erythrocytes that have been pulled aside

and need to be recycled and get sent to

the liver where they get recycled by

some of the useful basically the rest we

throw away hemoglobin bilirubin jaundice

makes you feel lost

yeah so that's the other function of the

spleen is to filter out old erythrocytes

and keep the new ones so this means that

if there is a pathogenic process or

pathological process that is changing

red blood cells so fallacy Mia or

malaria or hereditary spherocytosis

where the red blood cells become rained

then that disease processes process

changes the red blood cells and then

those red blood cells might get picked

out as in the spleen as needing to be

removed so then you start removing too

many red blood cells red blood cells and

then you get anemia sometimes removing

the spleen is the solution but not the

rope and we cut sections of a spleen and

stain FA astrology then of course we

change the colors of the cells we use

say hematoxylin Eocene to stain the

cells so that we can see this changes

the color so if we look at the histology

we can see a central blood vessel there

and surrounding that is is his white

pulp so of course it looks kind of blue

they'd be really nice things so given

what we know about a spleen what can go

wrong and because of where it sits under

the ribcage you can't normally palpate

it but it can become enlarged with liver

disease cancers of the blood or

infection and that's all thing that the

spleen might become enlarged and if a

patient breathes in then flattens their

diaphragm you may be able to palpate the

speed and spleen under the costal

cartilage if he enlarges it's going to

enlarge across the diaphragm in in this

direction because of course blood

cancers like leukemia and that sort of

thing they're gonna in terms of trauma

so the ribs that the spleen is under the

ribs so the ribs protect the spleen

however of course if you have a blow

sufficient to fracture a rib then that

the spleen as a risk of damaging from

being damaged by the rib itself in fact

just a blow to the side of the

of this region here can be enough to

cause the spleen to rupture because it's

just got that little thin capsule over

the top of it and if it ruptures and it

sees an awful lot of blood then you may

come across a bleeding internally so

somebody is losing blood into their

abdominal cavity I mean the signs of

this are if you think about it dizziness

increased heart rate to cope with the

lowered blood pressure and if you can

measure it a lowered blood pressure so

watch out that a ruptured spleen is a

medical emergency that person needs to

go to the hospital now and hopefully the

spleen can be repaired and but it can be

difficult because this capsule and what

have you it possible the spleen can be

repaired in the and the blood loss

stopped it's not like a first choice

these days to just get rid of the screen

you know as like the first option but if

you can't stop the bleeding the patient

is losing a lot of blood in turning

there's a risk of them bleeding to death

and then to remove the spleen of course

you need to ligate the splenic artery

and vein be kind of want to do this as

close to the hilum as possible because

there are blood vessels in the past of

the stomach and blood vessels the past

of the pancreas from these arteries so

you know you don't want to cut those

organs off from blood supply and then

you remove the spleen and you stop the

bleeding but of course that person

person then doesn't have the benefits of

the store of platelets in the store of

red blood cells for possible future

trauma but the bigger problem is

infection that person is likely then to

be taking low dose antibiotics for the

rest of their life they need to pay

extra attention to signs of infection

because it's going to be harder for them

to fight infection and things like that

they won't be able to make the same

immune response of somebody with a

spleen because this bus what the spleen

is good at doing but they haven't got

one so they have to be more careful so

your spleen is important do take care of

your spleen but you can remove it and

live without it and of course the spleen

is also more likely to rupture

if enlarged so if you've got an enlarged

spleen you should probably avoid contact

sports and maintained by

you know skiing and things like that for

a bit so there you go hope you know

everything about the spleen what you

need to know now you know where it is

you know other organs are near by it

you know what it does we've had to look

at the cells yeah

now that much - it really is there okay

what I'm going to see you next time