Gross Heart Anatomy

Okay, so we're going to have a look at the actual dog heart now in the real thing.

So here's a canine heart from the left-hand side.

And you can tell it's from the left-hand side because the aorta's coming out here.

So in the dog here, the head would be here and the tail would be here.

So that's going back into the abdomen of the animal.

So if you think back to the diagrams that we labeled, this here then,

would be the left ventricle going down to what we wall the apex of the heart.

So the apex is the tip of the heart there.

Up here where all of the vessels are exiting and

entering the heart is the base of the heart.

So this largest chamber here, this left ventricle here and above there,

this was this fleshy part I talked about.

This is what we call the left auricle.

It's the little appendix on the left atrium that sits here

on the caudal aspect of the heart.

On the cranial aspect here then, under my fingers here would be the right ventricle.

And up here, as we saw on the diagram,

you can just see the fleshy bit of the right auricle peeking around

the cranial aspect of the heart there, right up next to the aorta itself.

Coming out of the right ventricle here, it's not so easy to see that this is

a vessel, but here, this part here, this is the pulmonary trunk.

So this is the blood coming out of the right ventricle then go to the lungs.

This is the deoxygenated blood, will come out here,and will divide into the left and

right pulmonary arteries to supply the left and the right lung.

If we flip it over and look at it from the right-hand side, so

now the animal's head would be here and the animal's tail would be here.

So on this side, I figure from the apex up,

here on the cranial aspect you still got right ventricle.

And on the caudal aspect you will have this left ventricle.

And this is the auricle again, and

this is covering then what would be the right atrium.

So that sits on the right side completely.

Feeding into that right ventricle we've got these two major veins,

and veins are so much thinner and more floppy.

So, if you compare this here to the aorta, you can see that the aorta

has got really quite a thick wall while this caudal vena cava coming in here,

which is larger in diameter, but it's got very, very thin flimsy walls.

So that's your caudal vena cava, and

it goes straight into the actual right atrium there.

And here is the cranial vena cava, and

that's feeding right into the right atrium as well.

So if I put forceps down there, you can see that ends up into that chamber there.

The other things that you see here, you can actually see here,

you got the wind pipe.

The wind pipe is still attached to the top of the heart here.

And there's the main bronchi coming in to the lung.

And underneath that, this is actually the right pulmonary artery coming here,

and would be supplying the right lung at this point.

The other Entries that you can see here, like this one and

there's a few at the caudal aspect here, these are the pulmonary veins.

So these are the veins coming back from the lungs with oxygenated blood and

they're going into the left atrium that's sitting there.

So that's the external surfaces of the heart.

Now I'll have a look inside the heart itself.

So this heart has just been sliced in two so

that you can see the actual chambers themselves.

One thing that's immediately obvious is the difference of the thickness of

the walls of the ventricles.

So the left ventricle is the one that's pumping the blood

all the way around the body, so really needs to work hard.

So you can see how thick the wall is on this.

So this would be the left ventricle here, and this would be the right ventricle.

And if you see the thickness of the wall of the right ventricle,

it doesn't need to be so thick, it doesn't need to work as hard because

all it does is pump the blood into the lungs.

And then, when we label the diagrams,

the other thing we're talking about was all these valves.

And here, we cut through it, but you can see.

So this is your left AV valve.

And I think what's interesting about looking at that in detail

is how flimsy these structures really are.

And you think they hold all that blood back in the heart while it's contracting,

but the valve itself all it is is very thin.

But a very smooth surface on it.

It should be smooth because the blood should run

over it without any turbulence being caused.

So that's a nice smooth but very thin flimsy structure.

I've got a different heart here just to show you the aortic valve example.

So, the aortic valve has got a slightly different type of valve leaflet.

So, you often call this the semilunar because they look like a half moon shape.

So you can see that sitting there, it's a nice little half moon shape.

He's got three of those, and that's one of them there.

And again, you can see the AV valve here, that's the left AV valve again.

It's got these little tendons attaching it down to the muscle there, the cord or

tendon, but that's the valve itself, that smooth looking little structure.

So that's the hearts then.

Let's have a little look at the lungs themselves.

So here we've got some dog lungs.

They have been split into two parts, and

the windpipe has actually been removed here.

So if this was in the animal, the head of the animal would be towards me and

the tail would be that way.

And this is the dorsal aspect of the animal, so

this is up towards the back of the animal.

So this would be its left lung.

And as we said, the left lung has got two lobes.

And in the dog, the lobes are completely separate.

You can see there really are complete division between the lobes when you

look at it.

So this would be the cranial lobe.

And if you remember, we said the cranial lobe has got two divisions to it.

So it's got cranial division and the caudal division.

So that together makes up the cranial lobe.

And then the second lobe is the caudal lobe that sits here.

And the left side of the lung is slightly smaller because the heart lies a little

bit to the left, so that actually takes up a bit of room there.

So on the right side, we actually have four lobes.

So this would be our cranial lobe.

So this would tuck in in front of the heart.

Here would be your middle lobe.

And here would be your caudal lobe.

If I flip it over, and you'll see the fourth lobe on the right side,

that's the accessory lobe.

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