Well, now we're going to have a little look at different hearts. We'll do a bit of comparative anatomy. So this is the canine or the dog heart that we looked at in the previous video. And you can see this is from a relatively large dog. It obviously various a lot. Next to it here, I have a typical pig heart. This is supposed to be the one that's the most closely related to the human heart in shape and size really. So if you move up here then, this is horse hearts that I've got here, and we got two of them here. This is from the left-hand side, and you can see it's very similar when you look at these hearts. You see the same things, the apex, and the base. You'll see the same vessels coming in. That's the pulmonary trunk. That's the aorta. There are some variations that you can also see. At the aorta of the horse, we only have one large brachiocephalic trunk here. And if you look back, we didn't mention this earlier, but when we look back in the aorta of the dog, can you see that there's actually two vessels coming out of this level? So you got brachiocephalic trunk and the left subclavian artery. So there are some variations between animals, but other than that, they are very similar. You have your left auricle, you have your right auricle coming on. This is the cranial aspect, this would be your left ventricle. It's quite interesting looking at the large heart like the horse or the equine heart from the right-hand side. This one here has got some clotted blood within the caudal vena cava here, and it really gives this sort of feel of how large this vein actually is in life. This one has also got the windpipe intact on top here. But you can really see the size of that, and then here again we can compare it to the aorta. Again, have a much thicker wall but a smaller diameter, so a smaller volume in there. Quick look inside of the equine heart then just to have a quick look at the valves. So it's the same structure. You see it's these nice thin valve leaflets here. This is the left AV valve. You got these little tendons, these little chordae tendinaeae, they're going in there, just a larger version really. And then you look at the, this is the aortic valves in the horse here. Again, exactly the same, these half-moon-shaped valves making up the leaflets there. Next to here is the ox heart, and really, you can see there's a little bit of difference in the shape. The horse hearts tend to have a very sort of narrow tip to it onto the apex. I tend to recognize the ruminant heart because they have a lot of this very hard fat on them. But, again, it's the same layout. Here's the pulmonary trunk, and here's the aorta coming out, and that's the brachiocephalic trunk coming out. Again, the right ventricle is here, and that's the left ventricle. I also got a complete set of heart and lungs here. Again, we're actually looking at it here from the dorsal aspect. This is from a calf. So, this is the dorsal aspect of this lung. This would be its left lung, and you can see here is the heart. This is how the heart is tucked in underneath the left lung there. In the calf, there's slight variation again. The left side is the same. They got a cranial division and a caudal division of the cranial lobe and this caudal lobe. But on the right side, they actually have this cranial and caudal division of the cranial lobe as well. That's typical with ruminant lungs. And then they got middle, a caudal right lobe. And then you lift that up, and on the ventral aspect, you can see a little accessory lobe. Here you can see the windpipe coming down and then dividing into these two left and right bronchi. In the ruminants, you also have a third bronchi, one that comes off early. And you don't see that in the horse, or in the dog, or in ox for that matter. This third bronchi going into the right cranial lobe. We'll go on to a little bit more exotic species then. So we have a vast collection of hearts here. Here's a little selection for you. We start with this slightly smaller one. This is actually from a polar bear. So, it's got very yellow fat on it. This is quite an old specimen. This is one of our more historical ones. But this is looking from the left-hand side. Again, you can see the left there auricle. This would be the left ventricle here. You can just about, if I tip it over, it's covered in this yellow fat. See the right auricle coming around. But that's the polar bear heart. Here's the aorta coming up. And that is more like the dog. It's a carnivore, it's got two vessels coming off the aorta here, it's got the brachiocephalic trunk and the left subclavian. This large one here, this is from a hippopotamus. So, as the animals are getting larger, the hearts are getting larger. You can see the size of this pulmonary trunk. Again, we're looking from the left-hand side. Huge big pulmonary trunk, large artery here, the aorta coming out. But, again, is the left auricle there? There's the apex. And this would be into the left ventricle here. So if I open it up like that, you can see the very thick ventricular wall there. Large animal so it's got a lot of blood to pump around. This one here is from a camel. I always think the camel and the horse look quite similar because they got this very pointy apex. But it's got very distinct right ventricle sitting on the cranial aspect here. Again, we're looking from the left-hand side. You can see the left auricle there, and the right auricle coming through, and again, this would be a pulmonary trunk. And here is the aorta, very large vessel. Again, camel is quite a large animal. Then we come to this one. And I always think it's funny because this is sort of tall, slim, heart, and it comes from a very tall, slim animal, the giraffe. And it sort of looks like it should be in the giraffe when you look at it. Again, you have a pulmonary trunk coming out here of the right ventricle. So you can see it coming out here. You can see it's got very similar, these are the pulmonary valves here, the semilunar valves. This is the same as in the aorta. It looks the same in all the animals, just bigger or smaller versions of the same. So now we're going to look at some very large structures. But before that, I'll just take you right back to the beginning where we were looking at this little canine heart, and we were looking at these little aortic valve leaflets. So these thin, little half-moon-shaped leaflets and the little AV valves like that. So looking at the aortic valve, and this is from a whale, and this is basically the aorta itself. This is one of our historical specimens here. And if you look in from this side here, this bit here is one of those half-moon-shaped valve leaflets there and you got three of those making up a nice aortic valve there. This is a part of a newer specimen. This is a fin whale that was beached a couple years back. And you can see here this is a bit of a AV valve here. You can see the nice chordae tendineae here, the nice smooth, sort of surface of the valve there. And we got more of that heart over here. So this bit here, this is one piece of the heart, and this really corresponds to just what we've got here. You've got your, this here is your AV valve. So we really just cut out this little piece of the heart like that from this. And that's what we've got sitting here on the table. So, again, you can see a nice AV valve here which is chordae tendineae. And then you can see, if I lift this up, it's a bit hard to see, but here again you can see nice aortic valve leaflets. So that's half of one of these half-moon-shaped leaflets there. And there's another one. So this is where the aortic valve sits coming out of the left ventricle there. So, this is just one small piece of the heart. This heart in its full size, it would be taking up, it would be right next to me, it would be like a small car next to me there. So it's really a very large structure.
