Overview of Tissue Structures - Video Tutorials & Practice Problems
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1
concept
Cells to Tissues
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Hi in this video we're gonna be talking about the evolution of tissue structure. So first let's talk about how cells became tissues. So before they were multicellular organisms, they were all of these single cells just sort of floating around. But eventually they started interacting with each other and found that that was beneficial. And so to increase these interactions, cell to cell interactions lead to the formation of an extra cellular matrix in the first and the first multicellular organisms. So the extra cellular matrix is really just composed of these proteins that connect cells together. So meta zones, which is another term for just multicellular organisms, evolved from these really small cellular colonies of cells around one billion years ago. And so when they did this, they needed to be able to attach together. So one of these proteins that did this is called the cell adhesion protein or molecules that you can do cam for short and they attached animal cells together. Animal And so these are obviously still present today um and they still attach animal cells within our bodies and with other animals bodies. Now for plant cells, this term is a little different and it's called plasma does Mata which are actually just the cytoplasmic bridges that connect plant cell walls. Now, if we refer back to the extra cellular matrix, which again we're talking about all of these things that connect cells together. The extra cellular matrix is composed of multiple proteins. Um some of them called the basil lamb inna which forms the base alumina that provides support instructors for groups of epithelial cells. So there's been a lot of molded words but all of them are responsible for attaching sales together. There's a lamb in a does it through proteins, plasma dis model does it through cytoplasmic bridges but all of these are connecting sales together. So here you can see so here in this image you can see animal cells. This is actually animal skin and plant cells. So this down here is going to be the extra cellular matrix which you can shorten with E. C. M. And then you have the basil lamin A. Which is actually this uh black structure here. And um pretty much both of these are just consists of all of these different proteins that help attach all of these cells that are up here together and help them act as one force as as skin instead of all of these individual cells. Now for plant cells. Um like I said there were it was called plasma does Mata which is down here at the bottom back up so you can write that down Plasma does Mata. And you can actually see them here. Um Yeah the green shows up so um you can see the cytoplasmic bridges or plasma does Mata connecting all of these plant cell walls together. Um So this is how cells eventually started evolving into tissues because they were acting as one unit connected by all of these proteins instead of all of these individual cells. Now today we have tissues and so organized groups of cells form tissues. Now I've divided this into two section different types of plant tissues and different types of animal tissues. And I bowled id some of these terms that you're probably familiar with from your intro bio class which went over some of the basics of tissues. So this is mainly just a refresher of what uh the issue terms are for plants and animals. So for plant cells you have ground tissue which is the area of metabolism you have dermal tissue which forms the protective coat. It is also a place for nutrient absorption and then you have vascular tissue which transport water and nucleus throughout the plant. Now for animal sales you have five main tissue groups epithelial which forms sheets that cover the body for protection. You have connected tissue and that provides the mechanical support for the body. This also includes your bone tissue. You have blood which is responsible for transporting oxygen throughout the body. You have the nervous system which is responsible for transporting signals throughout the body. And then you have muscle tissue which is responsible in helping your body move. And so um like I said, these boulder terms you're familiar with already from your bio, your intro bio class but I just wanted to refresh them here. So we can understand, you know, these are the tissues that groups of cells make. So if we look at the plant tissue here, you can there are a bunch of numbers here. You can kind of just ignore them. But you can see the vascular tissue which transports the water. And you don't necessarily you don't need to know exactly where these tissues are just that they exist on this plant. Uh This plant cross section actually of the three tissue types. So then you also have the dermal tissue which provides support and structure and protection for the plant. And then you also have um the ground tissue which is responsible for absorbing nutrients and helping things flow between all the different tissues. So now let's move on to the next concept.
2
concept
Multicellular Development
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6m
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So we talked about cells and tissues. But now let's talk about the formation of multicellular organisms. So first the formation of tissues has to occur has to happen early in the development of an organism. And so this is because in the human body a single cell which is called a zygote, which is the first single cell eventually result in 100 trillion cells. So that's a huge amount of diversity and complexity and number of cells. So in order for that to happen, the cells have to decide very early on what they're going to become. So they have to say, okay, you're going to become this. So you need to focus on becoming blood or you're going to become the head. So you need to focus on doing that. And by separating those divisions and those responsibilities out early, we're actually able to form this functional organism instead of a jumbled mass of cells. So one of the earliest patterns actually depends on the placement of where your mouth and the anus goes. So in protas OEMs which are a type of or um it's sort of a division of organisms, the mouth. So there's they developed the mouth near this thing called a transient opening and they have eventual nerve cord. Now you should have gone over this in your bio one on one class. Um So this is just really a refresher for you. But in early development there's this kind of hole that opens, which I'll actually just show you down here. Um so you have um so here's some of these very early cells before the opening. But eventually this opening starts forming this transient opening right here and then depending on where whether the mouth forms near this or the anus form here and that's how you're classified. So for protas OEMs the mouth um develops near this transient opening so eventually the mouth will form down here. Whereas in diaries owns the anus forms near the transient opening opening so you can see this um down here and so this really starts to divide how organisms eventually develop. So for protas OEMs they have a ventral nerve cord and for Judaism's they have a dorsal central nervous system. Now you don't necessarily need to remember what the dorsal central nervous system just know that these um different classifications affect how the multicellular organism is developed. So now the a second large type of patterning occurs and this is actually for patterning genes. So master regulatory pattern genes control the timing and formation of specific tissues. So before we were just talking about mouth and anus. Now we're talking about specific tissues. So this type of symmetry that's controlled by patterning genes includes anterior posterior dorsal ventral to which side of the body you're talking about. And then it also controls where the head, the chest, the abdomen and tails are going to develop. So what are patterning genes? What do they do? Well actually they are pretty conserved. So I mean they're found in almost every organism pretty much every organism. Things called transcription factors. and what transcription factors do is that they control gene expression which makes sense. You need to control the development of cells and tissues. Well then you have to control the genes that are expressed in them. So pattern genes are transcription factors that control gene expression. Um and so they can be I mean like really specific. So for instance um the gene that controls the development of eyes is actually the exact same gene in flies and in humans. Now this might seem a little weird because the fly i is very different than the human eye. But it's true because they're both eyes so very early in development, they are controlled by the same patterning gene. And so this is actually a so I want to show you this image. It has a lot of colors to a lot of aspects to it. So let me walk you through it. So this is actually a fruit fly. Um Zygote. So a very early in development of the fruit fly. And um they so you can see that they're all of these different colors. So all of these different colors have names. You don't need to know the names. Just sort of know that these are jeans. These are patterning jeans. So this is gene one gene, red, green, blue, jean purple and so on so forth. Now. So it is this is kind of a graph. So you have the anterior and posterior moving across here and then you also have the time. So this is earlier in development and later in development. So you can see that this um this very early organism expresses this blue gene on the anterior side and the red gene on the posterior side very early in development. And this stimulates the formation of tissues in this area. Now as it progresses on in time, it stops expressing this blue and starts expressing these purple and green jeans. But it only does it in these very specific locations. And you can see that they actually over time become extremely specific. Where you can see that right here and here there are these blue jeans expressed, but in this area between them there's not. And so these patterning genes over time lead to complex structures found in organisms that can lead to various organs or symmetry. And that's what allows us. These patterning genes really control early development of specific structures in an organism. So now let's move on.
3
Problem
Problem
Choose which of the following is true:
A
Protostomes and Deuterostomes describe the formation of eyes during development
B
Patterning genes are transcription factors that control the expression of important developmental genes
C
Ground tissue is found in animal cells
D
Plat cell walls prevent communication and connection between adjacent plant cells
4
Problem
Problem
Which of the following is not a tissue type in plants?
A
Ground Tissue
B
Dermal Tissue
C
Mesodermal Tissue
D
Vascular Tissue
5
Problem
Problem
Which of the following is the name for the group of genes that control development of different body regions (ex:anterior/posterior, dorsal/ventral)?