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Cuttlefish Disecction - Contenido educativo

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Subido el 26 de julio de 2023 por M Pilar De M.

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This cuttlefish dissection movie was done firstly for the bilingual students of 1ESO of our High school Severo Ochoa of Alcobendas. In it, the external and internal anatomy of this invertebrate mollusk can be see and explain by our American auxiliary Avery Masters. The objective is to revise the contents shown in the previous experience in our lab and to practice the pronunciation.

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Okay, welcome. We're going to dissect a cuttlefish today. So this process is going to involve 00:00:00
different tools from the laboratory, and I will be recording this in English so that 00:00:14
for the bilingual students, you can practice the vocabulary and the technical terms for 00:00:19
this animal and the process of dissection. For any lab, you need the proper tools. In 00:00:25
this lab, I will be using gloves, which are plastic protectors. Okay, we're going to use 00:00:30
gloves. We will use a scalpel, scissors, and tweezers. Often, our specimen is placed on 00:00:37
a tray. In this case, we will use cork, so it's more visible for the camera. First, we're 00:00:46
going to examine the external structures of this animal. We have the dorsal side, underneath 00:00:50
which is the cuttlebone. This is the part of the animal that camouflages with special 00:00:56
pigment cells, changing color to blend into its environment when it feels threatened by 00:01:02
an attacker. On the opposite side is the mantle, a soft, fleshy covering that conceals the 00:01:09
organs and protects them. The animal is a decapod. It has ten tentacles in all, eight 00:01:18
of which you can see here because they are small and short and covered in suckers, and 00:01:26
two of which are tucked into sacks in the animal's head because they are released to 00:01:32
catch prey. So, the longer club tentacles are kept inside and ejected from this animal 00:01:39
when necessary to catch prey and bring it back in towards the mouth and beak, which 00:01:48
is here in the center of all the tentacles. You can see it here. Also, we know that this 00:01:56
is a club-footed or cephalopod, so the head and mouth are both here, and there is a U-shaped 00:02:02
digestive tract, which we'll look at when we cut this animal open. These are the main 00:02:12
characteristics externally of this animal. As we spoke about, the tentacles, there are 00:02:17
ten total, ten, the Latin word for deca being the Latin word for ten. This is a decapod. 00:02:25
We have two long tentacles that end in clubs and eight shorter arms that attack the prey 00:02:32
once it is within reaching distance. And finally, in the exact center of all of the tentacles, 00:02:41
we have a structure that looks exactly like the beak of a bird, like a parrot, that is 00:02:48
the mouth organ, and it's deep inside here, so I'm going to pull it out so we can take 00:02:55
a look at it. This is like the beak of a parrot. It's hard, and it opens, it hinges, there 00:03:00
are two pieces, and it cuts the food into tiny pieces because the esophagus, where the 00:03:08
food must go to get to the stomach, is small and it runs next to the brain. So it's vitally 00:03:15
important that this animal cut all its food into very small pieces because it's going 00:03:21
through a tiny tube to get into the stomach, and it is passing the thinking organ of this 00:03:27
creature. On either side of the mouth, we see the eyes, and directly below is the brain 00:03:34
organ, the mouth organ. One final important external structure of this animal is its funnel. 00:03:40
This is not a tentacle, it is a part of the jet propulsion system. The fin is used to 00:03:48
balance, but the animal propels itself through the water by allowing water in through a water 00:03:55
entry, and then shooting that water out through this funnel, this water exit, thus propelling 00:04:03
the animal through the water instead of using a tail, fins, or flippers like other aquatic 00:04:10
creatures. We're going to start cutting this animal open. So to get to the organs, which 00:04:17
we know are below the mantle, we're going to make an incision along the fin, and then 00:04:26
open the mantle like this. We've now cut the mantle open, and the organs of this animal 00:04:32
are exposed. Part of the mantle structure are buttons and buttonholes, which fasten 00:04:37
like the buttons of a coat to protect these organs from damage and from any threat that 00:04:43
might occur in the water. We can see the opening of the water entry and exit, and this is what 00:04:50
allows the jet propulsion to happen, which is the entire moving apparatus of this animal. 00:04:58
The breathing apparatus is here on the two sides. These are gills, and they're connected 00:05:04
to bronchial hearts so that the animal may breathe underwater. At the very front of the 00:05:10
tip of this part of the animal, we have the reproductive structure. These are eggs, this 00:05:17
is a female, and they are released into the water once they are fertilized to produce 00:05:24
young. Directly next to the eggs, we have the ink sack, which is connected to an ink 00:05:30
siphon, which allows this animal to shoot ink into the water to confuse prey when it 00:05:36
feels threatened. The bright orange organ here is the needamental gland, and the larger 00:05:42
white organs are albumin glands. We have the fin, which edges the entire external structure, 00:05:50
and we have the oviductal pore, which is directly next to the gills and can be seen right here. 00:05:59
Those are the organs that are immediately visible once you cut the mantle. Directly 00:06:08
connected to the gill is the bronchial heart. We can see that here. Then underneath here, 00:06:12
we have the esophagus, and we have the ink track. This runs directly from the ink sack 00:06:19
and shoots out in the funnel. This is the needamental gland and the albumin gland. Here 00:06:27
is the liver of this animal. I'm going to make an incision here directly along in the 00:06:34
center, right in the center of the liver, which will, again, with great care, because 00:06:39
this animal doesn't want to bleed onto the other organs. If we pull apart the pieces 00:06:47
of the liver, we can see the digestive tract right there. This is the liver, and here we 00:07:01
have the gills connected to the bronchial heart. There are two bronchial hearts, one 00:07:09
on each side of this animal. If we go even further, directly underneath this, in this 00:07:16
area, is the stomach of this animal. We're just going to make very careful incisions 00:07:24
to reveal the stomach so we can take a look. Under the ink sack and the glands, the stomach 00:07:31
is revealed. These are more eggs. Here are more eggs in the front of this area. These 00:07:49
are what will be released into the water right there, a very clear vision of the eggs. 00:07:57
The ink sack, as you can see, has broken. There is a slight hole in it, and that makes 00:08:05
this whole process more difficult because the ink will obscure our vision of some of 00:08:11
these organs. We have to be really careful not to break it even more. Here, as you can 00:08:17
see, is our stomach organ. Here is our bronchial heart. Here is our gill, and here is the liver. 00:08:22
As you can see, just below the bronchial heart, we have the kidney. There are two kidneys, 00:08:30
one below each of the two bronchial hearts. As we know, this animal is using jet propulsion 00:08:36
to move through the water. The funnel, which we took a look at earlier, I'm going to cut 00:08:43
this external structure open so we can see exactly how the process of jet propulsion 00:08:49
works. This is a hollow tube. Very difficult to see, but right here is a flap that allows 00:08:55
water out. It is a one-way trajectory for this water. It may shoot out of the animal, 00:09:04
but it blocks water from coming back in. Once the animal has allowed water in, it shoots 00:09:11
it out to move forward. We've talked about the U-shaped digestive tract, where the stomach 00:09:18
and the esophagus runs directly through the brain and the head of this animal. One of 00:09:26
the most interesting parts of this creature is that it has one of the most complicated 00:09:30
eyes of any invertebrate. It has a lens exactly like the lens in our eyes that, in fact, all 00:09:38
vertebrates have. I'm going to cut this eye directly around so that we can remove one 00:09:46
of the eyes and take a look at its internal structure. It's very delicate. Don't want 00:09:57
to break it. It will bleed. Now we're a little tricky because it has a protective cover. 00:10:06
What we're doing is cutting the eye completely away from the body so that we can take a look 00:10:16
at it. This is the brain. Here is the brain. The brain is directly in the exact center 00:10:23
of the head. We know that the esophagus runs through it and the mouth is here. That's why 00:10:31
it's U-shaped as a digestive tract. We have an eye, which we've separated from the body. 00:10:36
We can see this is the covering of the eye. Now we're looking at the actual pupil, the 00:10:42
center of the creature's eye. What we want to do is very gently, very, very gently remove 00:10:48
this part of the eye, which is difficult to do without breaking. I'm going to attempt 00:11:00
to do now. This is what we're talking about. This is the lens, this very special piece 00:11:08
that is almost unheard of in an invertebrate. This is an incredibly complex animal with 00:11:19
an eye like our own. You can find this in a human eye and it's here in an invertebrate, 00:11:26
which is highly unusual as a phenomenon. We're looking at some of the different pieces 00:11:31
of this eye, the lens, the protective covering. Then as it connects back to the brain directly, 00:11:37
which is also proportionately very large for an animal of this size. In Spanish, this part 00:11:44
is Humor Acoso. We don't know its actual meaning in English. I'm sure it's a cognate. We have 00:11:52
the lens here. It's a fascinating piece of this animal. The lens is different than the 00:11:59
lens in our eye in that it is better for seeing underwater because the light diffraction is 00:12:08
different underwater than it is in the air. This has been specially tuned to the light 00:12:14
that is accessible to this animal. When we talk about the different lines of evolution 00:12:20
between a vertebrate and an invertebrate, the idea that an invertebrate has lenses of 00:12:27
this type means that it is just a reaction to the light and to the atmosphere in which 00:12:34
this animal lives. It's really, it's truly, truly scientifically a fascinating part of 00:12:40
the cuttlefish and looking at what this animal can do. 00:12:47
For more UN videos visit www.un.org 00:12:57
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Idioma/s:
en
Autor/es:
Pilar de Miguel Ceñal
Subido por:
M Pilar De M.
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
217
Fecha:
26 de julio de 2023 - 14:27
Visibilidad:
Público
Centro:
IES SEVERO OCHOA
Duración:
13′ 20″
Relación de aspecto:
5:4 Es el estándar al cual pertenece la resolución 1280x1024, usado en pantallas de 17". Este estándar también es un rectángulo.
Resolución:
720x576 píxeles
Tamaño:
153.98 MBytes

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