MARIAN DIAMOND: Have you
thought about your muscles
this morning?
Oh, yes.
All right.
Well let's learn then
about the femoral triangle.
Have you ever heard of
your femoral triangle?
Can you guess where it is?
Good guess.
All right.
Femoral triangle.
So landmark number one will
be the inguinal ligament.
So let's put that in.
Here's our inguinal ligament.
And that came from the
anterior iliac spine.
Put your hand on your
anterior iliac spine.
Get to know it.
Right there.
Feel it?
Come around your ileum and
come before it dips in.
That's the anterior iliac spine.
So that's what this point is.
This point will be
your pubic tubercle.
And since we know this is the
superior aspect of the muscles
of the anterior thigh, we can
put a line here and a line here
and this will be lateral
and this will be medial.
And who's going to
tell me what muscle
is crossing from the
anterior iliac spine
to go down to the medial aspect?
What is it?
Sartorius, sure.
So we're going to
put in the sartorius.
And now we've made a triangle.
What's important
about that triangle?
Quite a bit.
What are the contents
of the triangle?
One, we'll have
the femoral nerve.
The femoral nerve.
We'll have the femoral artery.
The femoral vein.
And now to make the
word we want to make
we have to stretch
a little bit so we
say we have an empty space.
There are no empty
spaces in your body.
But we need an E here,
so we'll do that.
And then we need an
L and our L will be
for lymphatics and lymph nodes.
So if we take our letters
and put them in position
we'll have the nerve, then
the artery, then the vein,
then the empty space, and then
the nodes and lymphatics here.
So this will be
our N. This will be
our A. This will be our
R, our E, and our L.
So what does it spell?
Navel.
That doesn't help
you any, very much,
but it lets you know
what major structures are
right here at the superior
aspect of the groin.
So if you have to go in for the
femoral artery for a pressure
point, somebody is bleeding
significantly in the leg,
you can pick it up right here.
Did you know that
was at the surface?
Did you?
No?
Are you listening?
OK.
I get no response.
So now then let's look
at the posterior thigh.
Muscles, continue
with our muscles.
Take the hamstrings
and the muscles
that constitute the hamstrings
on the posterior thigh
will be what?
The rectus femoris,
the semimembranosis,
semimembranosis, and
the semitendinosis.
I think I put an extra U in
this one that doesn't belong.
Let me take it out.
So these will form- yes?
STUDENT: Is this the
biceps femoris [INAUDIBLE]
rectus femoris
[INAUDIBLE] quadriceps?
MARIAN DIAMOND: This is
the biceps, thank you.
I'm having too much fun
with you that I didn't
get a clean synapses there.
I apologize.
It's the-- thank you.
Always correct.
If I can correct you,
you can correct me.
Right?
So this should be biceps
femoris, I apologize.
We know it has two heads.
So these give them the shape
to the posterior thigh.
And we're going to have two
heads for our biceps femoris.
One will be on the
ischium and the other
will be on the distal femur.
So we want number one here.
Origin the ischium
and distal femur.
And for two, we'll just have
the origin, that's the ischium.
And three, the ischium.
And they will all insert on
the proximal medial tibia.
And what is their
action going to be?
They're crossing one joint here.
What are they going to do?
They're back here
when they contract?
What are they doing?
No, that's not flexing.
They're back here.
Here's your ischium
and you're coming here.
They're going to contract.
What is this?
Extending.
Extending.
Extending hip.
But then they're coming
on down to proximal tibia.
So when they-- what
are they doing here?
What's that at the knee?
That's flexing.
That's flexing the knee.
All right, that gives us
our posterior thigh muscles.
And then let's go to the--
do we want to do
anterior thigh next?
Let's see what we want to do.
Posterior thigh.
Let's do medial thigh.
Medial thigh.
So medial thigh will be
coming from the pubic bone.
Medial thigh coming down to the
medial proximal tibia or origin
at the pubic bone.
And we'll insert down on
medial proximal tibia.
And what will it do
when it contracts?
It will adduct the thigh.
It's an adductor.
And it can flex the knee
because it's going to the tibia.
It's crossing that joint.
Let's go to the anterior leg.
I just picked the
easy ones for you
so you get some
muscles at each level.
This one will be the
tibialis anterior.
So you can guess where
it's going to be going.
It will be coming
from the lateral head
of the tibia and
the shaft and it's
going to go down to
the first metatarsal
and first tarsal bone.
So for the tibialis
anterior, it's
going to originate
from the lateral tibia
in the proximal position.
And it's going to
cross, anterior
tibial coming across
the tibia to insert
in the first metatarsal
and the first tarsal bone.
So now who's going to tell
me what the function is going
to be as we go from
lateral here, cross over,
come around to our instep.
When that contracts, what's
it going to do to the foot?
It's going to invert
it to do that.
That's inverting.
But it's also
going to dorsiflex.
This is the dorsum of the foot.
If I'm going to flex
it, that's dorsiflex.
So invert and dorsiflex
for action here.
So this brings us then
to posterior leg muscles.
Yes?
STUDENT: [INAUDIBLE].
MARIAN DIAMOND: On
the medial thigh?
Didn't I give you the name?
That's the gracilus.
The gracilus,
equals the gracilus.
What does gracil mean?
She's a gracil young lady.
Slender.
Slender.
So this is a thin,
slender muscle.
All right, then we
want posterior leg.
Everybody knows the
posterior leg, right?
What's it called?
You have two muscles
on the posterior leg.
The superficial one
is the gastrocnemius
and the deep one is the soleus.
So superficial equals
gastrocnemius and the deep
is the soleus.
So what do we know
about the gastroc?
It gives the shape
to the posterior leg.
And it's very large.
And having a large gastrocnemius
is part of the human condition.
Do you know any other animal
that has a large gastrocnemius?
It's a human characteristic.
I used to say that the
difference between Cal
girls and Stanford girls, we
have all these hills to climb
and they were
walking on the flat.
So we all had bigger
calves than they did.
But now with all your
treadmills and everything,
it sort of is reducing that.
So you can't use that anymore.
But the gastrocnemius now
is going to originate where?
Does anybody know?
It's going to originate at the
medial and lateral epicondyles
of the femur, medial and
lateral epicondyles of femur.
Now everybody knows where
it's going to insert.
Where?
What's the name of the bone?
Come on.
I'll wait.
STUDENT: Calcaneus.
MARIAN DIAMOND: Calcaneus, sure.
What's the common name?
Heel bone, right.
So it's going to insert on
the calcaneus via the Achilles
tendon.
Inserts on calcaneus
via the Achilles tendon.
You want to
incapacitate somebody,
you cut that tendon, right?
You don't go very
far without that.
So the action here,
it's coming to my heel
and it's contracting.
What's it doing to my foot?
It's called plantar
flex, plantar flex.
So we had dorsiflex
coming this way.
Plantar flex, I always think
you're planting your foot
on the ground.
It's going that way.
To do that, my gastroc
is contracting.
So now the soleus is
deep to the gastroc.
So it's originating, well
let's put in action here.
Plantar flex, we got that.
That's its main function.
And the soleus it will originate
from the proximal fibula
and femur.
So it's not crossing the joint.
This will be proximal
tibia and fibula
and will be inserting in
the Achilles tendon too.
When you study
muscle physiology,
you'll get the difference
between these in their capacity
to function.
They do differ.
Then the action would be
again the same, plantar flex.
So that gives you some of the
basic muscles of your lower
extremity.
So with that introduction
to our muscles,
let's now look at the
histology of muscles.
How are muscles built?
We are three different
kinds of muscles.
Probably something you
got in your basic courses.
Three kinds.
This is histology, which as I
said is the science of tissues.
And we have three kinds
of muscles, muscle tissue.
We have smooth,
cardiac, and skeletal.
These all differ in structure,
in function, and location.
So we'll take each one
and see how it's built
and where we find
them and why we
need different kinds of muscle.
So we're taking smooth.
What's another name for smooth?
Pardon?
Visceral.
Why could it be called visceral?
Because it's found
surrounding viscera.
What are viscera?
They're hollow organs or tubes.
Viscera equal hollow organs,
different from her liver,
or tubes.
Or it's called involuntary
muscle, involuntary.
Can anybody control
consciously your pupil?
Other than looking at light.
No.
So it's involuntary, right?
Now as we look at this muscle,
it consists of single cells.
And these cells are tapering.
They have a central nucleus.
They're tapered.
They have a central nucleus
and we find them in sheets
so that they can act in mass.
Act in mass even though
they're individual cells.
And they're held together by--
what are you going to
hold them together with?
What kind of tissue?
Connective tissue.
So we'll have a connective
tissue just represented simply.
CT, which binds these allows
a contraction in mass.
Now they do not have
striations but they have
a protein that can contract.
So let's see where we
find smooth muscle.
Where is the largest
mass of smooth muscle
in the human body?
Largest mass in body.
Where is it?
STUDENT: [INAUDIBLE].
MARIAN DIAMOND: No.
STUDENT: [INAUDIBLE].
MARIAN DIAMOND: No.
STUDENT: [INAUDIBLE].
MARIAN DIAMOND: In female.
STUDENT: Uterus.
MARIAN DIAMOND: Uterus, yes.
I just said body, right?
So this is going
to be the uterus.
When we study it,
we'll see it's shape.
It's designed to have powerful
contraction to expel a baby.
I heard you say it before,
where else we have it.
The GI tract, the
gastrointestinal tract.
Gastrointestinal tract.
And there it's designed to have
slow, rhythmic contractions,
pass the food along or
waste as the case may be.
Slow, rhythmic contractions.
And then where we need
muscle for endurance.
Where do you think
you're going to have
smooth muscle that illustrates
tremendous endurance?
It's a good guess,
but that's not right.
This will be at the
pupil of your eye.
All the time, every time
you look at your paper,
it's expanding, you look away,
it contracts and so forth.
Constantly.
So in the pupil,
control of the pupil.
Where you will have
muscle that's--
this is the iris.
This is the pupil.
And you'll have radial
muscles like this.
Now put together what
you've been learning.
What do these radial muscles
do when they contract?
What are they going
to do to the pupil?
Dilate, sure.
These dilate the pupil.
Begin to think.
And then we've
got circular ones.
When they contract,
what are we going to do?
Constrict, right.
So circular ones will constrict.
So constantly as you're
looking at all times,
these are working.
So now we need to devise
another type of muscle.
So let's look at
our cardiac muscle
and see how it differs
from smooth muscle.
It's going to
differ in that we're
going to have tubular
cells not the tapering kind
we saw in smooth muscle.
They're going to
have central nuclei.
But they're going to branch.
They'll have
striations and they'll
have intercalated discs,
intercalated discs.
So let's see an example
of a cardiac muscle them.
So we'll have a tubular cell.
It's going to come along
and it's going to branch.
It will have central nuclei.
It will have intercalated discs.
Where have you seen an
intercalated disc before?
Ever?
Any junction ever looked
like an intercalated disc?
What's it doing?
It's facilitating the
rate of transmission
here along the fiber.
Facilitates the
spread of contraction.
So it's a modified junction
between nerve cells,
which is much more efficient
than between other cells.
You have intercalated discs.
So the minute you see those, you
know you have cardiac muscle.
Then we have our striations.
So that gives us our
basic characteristics.
Now we move on to
skeletal muscle.
How many times does
your cardiac muscle
have to beat every minute
that you're sitting there?
About 72 times
per minute, right?
Cardiac muscles contracting.
Do you think that skeletal
muscle can do the same?
I have to do this so
that you really know it.
We're going to close
our fist 72 times.
See how your hand
feels after one minute.
1, 2, 3-- come on--
4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16, 17, 18, 19 20,
21, 22, 23, 24, 25, 26, 27, 28,
29, 30, 31, 32, 33, 34, 35, 36,
37, 38, 39, 40, 41, 42--
you've got fibrillation--
42, 43, 44, 45, 46, 47, 48, 49,
50, 51, 52, 53, 54, 55, 56--
you're not doing it back there--
57, 58, 59-- this is a
hands on science class--
57, 58, 59, 60, 61, 62, 63, 64,
65, 66, 67, 68, 69, 70, 71, 72.
Can you imagine?
Your heart does
that for 100 years?
And never stops.
Isn't that phenomenal?
Can you see why you
need a different kind
of muscle for cardiac muscle
versus skeletal muscle?
This was skeletal muscle.
No better way than
to illustrate why
we need different
kinds of muscle, right?
How does it feel?
Tired?
Sort of.
All right.
So let's look at skeletal
muscle and see how it's built.
So we've already
studied skeletal muscle.
We know it's shape.
We know it's size.
We know its location.
And now we want to
see how it's built.
What's the longest skeletal
muscle cell in your body?
Sartorius, right?
The longest muscle
cells are the sartorius.
How long did we say it was?
About 35 centimeters, 14 inches.
What's the shortest
muscle cell in your body?
Where are the smallest
bones in your body?
Your internal ear.
So the smallest muscles
are in your internal ear.
They say they're 10 mu.
Those are truly small muscles.
And think how they're
working for you now
to hear your lecture, right?
Everything you say, those
muscles are responding.
So here with this
kind of muscle,
since we can have
one that's so long,
we're just going to take a
part of a skeletal muscle.
First, we're going to have
peripheral nuclei, many
of them per cell.
We've got a cell that's
going to be 14 inches long,
we need lots of nuclei.
So we have peripheral,
multinucleated cells.
And we're going to
have a cell membrane.
We've had a cell
membrane with each,
but here I'm going to give
the terminology because we've
got to go on and define
the structures using
the terminology.
So the cell membrane for a
muscle is called sarcolemma.
What does "sarco" mean in Greek?
It means flesh.
So this will be the
membrane on the flesh.
Then the cytoplasm for a
muscle cell will be what?
If you had to name them,
what would you call it?
Sarcoplasm, sure.
Sarcoplasm.
So all of this is sarcoplasm.
Now within the
sarcoplasm, we have
myofibrils, bands, myofibrils.
And these myofibrils
are made up of what?
Good guess.
Myofilaments.
Myofibrils made up
of myofilaments.
What are myofilaments
made up of?
Actin and myosin, right.
Actin and myosin.
So let's show how
these are aligned
to give us our striations
in our skeletal muscle.
So we'll have one
of our myofilaments
to see what it's made of.
We're going to have myosin band.
Just what constitutes
the striations
as you can see them
with your microscope.
So in red, we have myosin.
Also called A bands.
Then in green, we could put
in our actin, much thinner.
Green, we have actin.
Called I bands.
You think when they named it
they could have made it easier
for us, so that the A
bands would be in the actin
and you'd have to As.
But you just have to remember
it's the opposite of what
you might think.
Now what's coming down
through our I bands?
Coming down the middle of
the I bands we have Z bands.
Now what's the area
between the Z bands called?
That's called you-- somebody
said it over here a moment
ago--
sarcomere, right.
So how are we doing
to define a sarcomere?
A sarcomere is the structural
and functional unit
of skeletal muscle.
It's the structural
and functional unit
of skeletal muscle.
So now we've had
two of these so far.
As we go through our tissues,
we're going to find these.
What was the structural
and functional unit
of compact bone?
Haversian system.
The canal is only the part
with the blood vessel.
The system is the
whole piece of bone
with the lamellae, the
lacunae, the whole unit
is a Haversian system.
All right?
So this is then the structural
and functional unit of--
you've got your Z bands
all the way along.
But now during
contraction of the muscle,
the Z bands approach each other.
During contraction Z
bands approach each other.
Now does that mean that
the actin and myosin
are going to change their
length during contraction?
No.
It's just that the Z bands
will decrease the sarcomere.
So how does this take place?
So we'll have a nerve
impulse to our sarcolemma
and the response is
transferred internally
to what's called your
sarcoplasmic reticulum.
This is your smooth
endoplasmic reticulum
in any other cell, smooth
endoplasmic reticulum, which
discharges a calcium ion,
and the calcium ion then
triggers the Z bands to move.
And you get the sliding filament
theory of muscle contraction.
All right with this
brief introduction,
it's really much more
beautifully complex.
But that's basic.
Let's look at slides.
First slide please.
Were going back
because we didn't
get to any slides last
time, so we wanted
to see our inguinal ligament.
Here's your anterior
iliac spine coming down
to the pubic tubercle.
This is your superficial
inguinal ring.
And we show the spermatic cord
coming up with the vas deferens
in it going through
the inguinal canal.
It has to go to the
deep ring and then
into the pelvic cavity.
And the next one.
And this shows the aponeurosis
over your abdominal muscles
in the medial aspect.
So here's your rectus abdominis.
We said the aponeurosis
was different,
superior to the umbilicus.
It was all going some in
front and some behind,
whereas below the
umbilicus it was all coming
in front to give extra support.
But then the aponeurosis
folds on itself
to form the inguinal ligament.
And then we have the
inguinal canal showing here.
But this would be our
external oblique muscles
going into the aponeurosis,
which will then
insert in the linea
alba, which goes
in this direction in midline.
And the next one.
And then these are the
muscles of the lower extremity
that we've been talking about.
You can see the sartorius
from your anterior iliac spine
coming around to medial tibia.
So it's going to flex the
hip and flex the knee.
You could see your
quadriceps tendon coming in,
then your patella,
and then your patellar
ligament coming in to insert
on your tibial tubercle.
We gave it tibialis
anterior that's
coming from a lateral head
here of the tibia crossing over
to go under the arch
to the first metatarsal
and first tarsal.
Then we had the
gastrocnemius and the soleus.
Superficial, the
gastrocnemius, beneath it
the soleus and the
Achilles tendon coming down
to insert on the calcaneus bone.
And the next one.
And what kind of muscle is this?
Smooth It's been put
in a solution that
dissolves the connecting
tissues and allows
you to see the
tapering smooth muscle
cell with its central nucleus.
And the next one.
Where are we going to find it?
Now when you'll
see it in a slide,
you don't see it separated
so beautifully as before.
This is all smooth muscle.
And the next one.
What's this?
That's smooth muscle
in cross section.
When you study
histology you have
to know it when
it's longitudinal
and when you're crossing it.
You might think this was
blood or something else.
And the next one.
What kind of muscle?
Cardiac.
How do you know?
Immediately, intercalated disks.
But you can see striations.
You can't see the branching
with this kind of preparation.
Next one.
What kind of muscle is it?
How do you know?
Where is the nucleus here?
Peripheral.
So you see it's really a very
different type of muscle.
Designed for very rapid
contraction in some cases,
but you can see your
A bands very clearly,
your I bands are in between.
And the next one.
What is this?
Showing a nucleus in cross
section, peripherally.
What kind of muscle?
Skeletal.
It's a skeletal muscle
in cross-section.
When you get to pathology
you've got to learn all of this.
In different sections, not
just textbook pictures.
And the next one.
What kind of muscle is this?
What's the slide demonstrating?
What do you think these are?
STUDENT: Blood vessels.
MARIAN DIAMOND: Blood vessels.
Good for you.
They've injected a dye
into the blood vessels.
Just look at the amount
of vascular supply
to your skeletal muscles.
Phenomenal.
And the next one.
Now this is the basic principle
that we were just showing,
a sarcomere was
between two Z bands.
Here are A bands,
here are I bands.
When these Z bands
come together,
the A and I bands
do not shorten.
It's just the distance
between the two Z bands.
So you get a picture like
this in full contraction.
What allows it to relax?
What substance allowed it
to slide to begin with?
Calcium Well the
calcium goes back
into the sarcoplasmic reticulum
and then your muscle relaxes.
Isn't that beautiful as
you walk across campus
and think about that?
All right, well,
that's it for now.
And we have our next lecture
starting at 12:10 today.
