Hello. Hello, you. Okay, today, I'm okay. Good. Okay. So we're back doing biology again today. We're going to continue where we left off from the other day. So just a quick reminder, the other day in biology, we were looking at what we refer to as biological molecules. So we were talking about carbohydrates, we were talking about proteins, and then we discussed enzymes as well. Now there was one final category of molecules that we didn't get onto, and that is fat or lipid. So that's what we're going to talk about first today. And then we're going na move on to the digestive system. So just as a reminder, carbohydrates, we said that they are used for energy. So we break carbohydrates down into sugars and we use that for energy. Protein was used for growth and repair. Now fats or lipids, these are also used for energy, but more long term energy. So fat is used as a source of long term energy. Okay, so when I say long term energy, it means that if we have sugar in our bodies, our bodies will use the sugar first because they prefer sugar. Sugar is an easier energy source. They can use sugar more readily. However, if we don't have any sugar in our blood or in our bodies or any stored sugar, we move on to fat. So somebody who has not eaten for a while, let's say let's say somebody who hasn't eaten for twelve to maybe 18 hours, so they've not got any sugar left in their body. We've used all the sugar up. The body needs to find a new way to release energy because we still need energy. We need energy to move. We need energy to breathe. We need energy for heart muscle contraction. So the body will start breaking down fat. Okay? So fat is a thicker substance. It's stored in fat cells in the body, but it's used as a long term source of energy, so like a sort of spare energy resource. Fat is also used for insulation. Now, when I say insulation, I mean keeping us warm. So fat is often described as a bad thing. And the type of fat that we tend to be referring to is bad. So processed fats, fats that come from processed food like chocolate and sweets, you know, Candy and cakes and processed food, fat in those foods is bad. It's not good for us. But there are good fats such as things like avocados, nuts, dairy. So unprocessed fats, even fats that's found in meat. So fat can be good for us because the monomers of fat, what fat gets broken down into, is a good source of energy, but it has to come from a clean, non harmful source of food. Another thing like I've said, here is insulation. So under our skin, so here is my arm. Okay? Under our skin, here we will have a layer of fat. Okay? Under here. Now you might, it might not be obvious, but the skin is quite stretchy. But under here there will be small layers of fat. You know, people have different varying levels of fat, but under the skin is a layer of fat. And the reason we have that as humans is to keep us warm, because fat is a good insulator. So fat keeps heat energy in the body, not too much so that we get too warm. But fat allows us to regulate our body temperature a bit better. It means that we don't just lose heat energy without being able to retain some. Can you think of an animal, Isabella, that lives in a really cold place that has a lot of body fat? Where live in I forgot the the White bear. White bear well done. That's I'm think of polar bears is what you're thinking. Wow so think polar bears Yeah excellent. Well done. That's exactly what I was thinking of so think polar bears polar bears live in the artics, the poles and they're it's really, really cold and they have lots of body fat to keep them warm. Same with things like seals that also live in cold climates, so they have a lot of body fat to keep them warm. So that's just a little bit of proof that shows that fat is beneficial in that sense. One last thing, fat is used to protect. Bones and organs. Now there is a fine line between the amount of the fat or the place that fat is, whether it's healthy or whether it's unhealthy. But a small amount of fat around the bones acts as a protection, because fat is like a soft squigy material, and it acts as a shock absorber. So if somebody bangs into something and they have fat around their bones, it's less likely to damage them. Now there is, like I said, there's a fine line because we have something called visceral fat, which is very unhealthy, but generally small amounts of fat in the body, good fats that come from clean sources of this type of molecule. They can be used for good and they are used for good. So foods that contain good fats are foods that contain good fats. Are things like, number one, avocados. I'm saying that it's very specific, but it's because avocados have become really popular in the past few years and they are a great source of healthy fat. Number two, nuts. So things like peanuts, cashew nuts, almonds, kind of the healthy fat that comes from nuts. Number three, dairy products. So eggs, cheese, yogurt, etc. And number four, meat. Okay. So meat fat tends to come from red meat, but their sources of good fat, sources of bad fat would be cakes, chocolate, Candy, ultra processed food. So food that has a lot of fat in it that maybe comes from a can, or fast food restaurants, for example. Things that we know, you know, we all eat them. We all do. We eat process essed foods at some point, but we know that they're not great for us, right? We know that if you have McDonald's, it's not good for you, but we still eat it sometimes. But good fats are a good source of clean energy, and they also help with these other mechanisms that we've discussed them. Now, if you remember, when we were looking at proteins and carbohydrates, we talked about what they get broken down into. So we said that starch is the big molecule, and it gets broken down into glucose. However, starch with enzymes gets broken down into glucose much faster. We also said that proteins, so this is an amino acid, and this is a protein. So proteins get broken down into amino acids. So the big molecules get broken down into small molecules. Now this here is a fat, okay, this is what we call a lipid. Now the word lipid is just the technical term for fokay. It can also sometimes be referred to as a triglyceride. But this is a fat slash, a lipid. Slash a triglyceride. Okay, so this is the big molecule. It doesn't really look like the other two, because when we looked at carbohydrates and proteins, we drew them as chains, didn't we? So this was a chain of amino acids, all joined together. This was a chain of gsugar, all joined together. So that's a little bit different, but it's still a really, really big molecule. Okay? So even though it doesn't look it, this here is still a really big molecule. So this is a fat lipid or a triglyceride. It is a large molecule, okay? So it's still a really big molecule in the digestive system. It is broken down, okay? So there are enzymes that break this fat down and they break it down into a few things, okay? So I'm going to show you what happens. So this would be the work of enzymes. So let's draw a new enzyme now. So these are the enzymes that break down fats or lipids. That's your enzyme. Remember enzymes speed up the reactions. There would be no reaction without the enzymes. They help the reaction to happen. Otherwise it would happen way too slowly, basically like this. Okay, so that's your enzymes. Now what this gets broken down into is quite a new term. Okay? So this one is is a bit different to the others, like I said. So fats get broken down by enzymes, so the process is the same. So fats get broken down by enzymes. In two fatty acids. Okay? So there are two products here, not just one fatty acids and glycerol. Okay? So they are your products of digestion, fatty acids and glycerol. This is the glycerol, okay? So the the one product there is the glycerol and these are fatty acids, so there are three of them. Okay? So there are three fatty acids and there are one or there is one glycerol. Okay? So that's what you have when you break a fat down, fatty acids and glycerol. So let's do a bit of a of a recap. Okay, I'm gonna to draw up a table here and we're gonna to fill it in. So we're gonna to say molecule. We're going to say use in body. So what do we use it for? We're going to say food source. What types of foods do we need to eat to get this food? And then the last thing we're gonna to say is products or monomers. So what it gets broken down into, I'll just put that as a question. What does it get broken down into? It get broken down into okay, so these are our four categories so I'm going to add in now the three molecules and we're gonna to talk through them one by one. So the first one is gonna to be the first one that we did the other day carbohydrates. Okay, so be having a think about carbohydrates. The one we talked about specifically Isabella was starch. So I'm I am going to use starch because that's the one we talked about. So the first molecule is going to be starch. And then we're going to talk about protein. And lipids as well. Okay? So starch is a type of carbohydrate. So just remember be thinking, what is it that we use starch for? What types of food do we get starch from and what does it get broken down into? So start, remember, was a carbohydrate okay, like this? Okay, what do we use starch for in the human body? What do we need starch for? Energy, well done. Excellent. So we use starch for energy. Well done. Energy. Excellent. What types of food should we eat if we want to get starch? Meet. Not me that saved that for a different one. Say that again. Rice. Rice. Yeah. Anything else? Okay, rice, ce is a good one. Pasta, potatoes, vegetables. Okay, so potatoes, vegetable. So well done. What does starch get broken down into? So when we eat it, what do our digestive systems break starch down into? Many parts. Yeah, it does. You're right. What do you remember what each of those parts were called? What if I give you the first two letters G, L? Okay, so glucose, or we can just call it sugar, okay? It's fine to just say sugar, simple sugars. Let me add simple to that. So glucose, or we can refer to them as simple sugars, okay? So at this point, we can still refer to them as simple sugars. So they get broken down in simple sugar, okay? What is protein used for in the human body? Wow. Wow. Good girl. Yes, well done. Growth is one of them. Growth and repair. So if you need to build new cells or if you need to repair the old ones, that's what growth and repair is. And there will be where proteins come in. Really handy. What types of food do we get proteins from? Vegetables maybe very small amounts, yes, but vegetables aren't really known for having protein in them. Again, not really. Think about something that you've already said today. Meat. Meat, yes. So meat, fish, dairy products as well like eggs, yogurts. Yeah eggs and yogurts generally. What does protein get broken down into? Now for this one, I'll give you the clue. There's two words, both beginning with a. Elecboth beginning with a. I forgot this one is amino acids. Okay, they get broken down into amino acids. Now the last one we've only just done so I'm not going to get you to talk about what does it get broken down into, but we are gonna to talk about the first two. So what have I said this morning that fats get used for in the body? Why are they helpful to us? Good to let us move. Yeah, in a way. What are they used for, fats? Not feel very cold. Okay. Yep, insulation well done. So insulation. Yeah. And then what did I say that we would use fats for if we didn't eat for a long time, what would our body start to use fat for? You use that. Energy. Well done. So installation and energy. So a long term or reserve store of energy, excellent. And then insulation to keep us warm. Okay. What kind of foods can we get good fat from that would be healthy for us? Fat but healthy. Yep, well done one more. Rice. There would be some, but I would think more avocados was another one. I said meat, nuts, avocado and dairy products as well. Okay. And then the last one is what does it get broken down into? And remember, there are two things here, fatty acids. And glycerol. Okay, so fatty acids and glycerol, fatty acids and glycerol, they are the molecules that we break fats down into in our digestive system. So what we're gonna to move on to next, Isabella, is the digestive system itself. Now I just wanna talk to you briefly about what the digestive system does. So the digestive system, now our digestive system is a few organs working together to help us to digest food. Now the role of digestion is when you eat food, the molecules in that food are really big. It's things like starch, protein, fat. So big molecules in our bodies, they can't be transported around very easily, because, as you can imagine, to get into and out of cells, we have to be small and really agile. Okay? So we want to break these big food molecules down into small molecules. And that's where the digestive system comes in. The digestive system's role, its job, is to break large food molecules down into small nutrients and then absorb them into the blood. So that's the roll. So the role of the human digestive system is to break large food molecules down into smaller nutrients, then absorb the nutrients into the bloodstream. The human digestive system is made up of many organs, all working together to complete this role. Okay? So they're all working together to try and get this job done. So the one thing it does at first is it breaks the food down, and the second thing is to move that food into the bloodstream. The final role is to get rid of any food waste. So the final role of the digestive system is to remove any undigested food from the body. As waste. So any food that we are not able to digest in the time that we have, we will remove it from the body. So every day or every couple of days when somebody goes to the bathroom, goes to the toilet, remove food waste from the body. That's a really important part as as kind of horrible as it is to think about, it's such an important part of the human anatomy and the way that human bodies work, because we have to remove waste from the body. So there's the three things that the digestive system does. Number one, break food down into small pieces. Number two, move those small pieces into the blood. And number three, get rid of any leftover waste. Okay, now we've talked a little bit about the point. Number one, we've discussed why it's important to make large food molecules smaller. Isabella, why do you think it's important that we put nutrients into the blood? Okay, why do you think that the food has to go into the blood? Why can't it just stay in the stomach or in the intestines? Why does it have to go into the blood? Maybe it cannot. Cannot. Cannot. Let people to, or it might stay at your stomach, don't cannot go out. Yeah, so if it stays in your stomach, it can't go anywhere else, can it? Why? Why do you think it's important for these nutrients to get into your blood? What's your blood going to do with them? What can your blood do? Okay, well, the blood is like the body's transport system, okay? So the blood is like the body's delivery system. You have blood everywhere in your body, every from the top of your head right down to the bottom of your feet. You have blood everywhere. If you accidentally cut your skin anywhere on your body, it bleeds, because we have blood everywhere. There is blood vessels in every part of the body. But if you look at this image, the digestive system is just here in the middle of the body, right? We have the mouth, a tube, and then this is your digestive system in the middle of the body. So the fact is, all of your cells need nutrients. Every single cell needs sugar, needs water, needs protein, needs fats. And if you don't let them come out of the digestive system, they're stuck there in the middle of the body. So how does your shoulders ever get any sugar? If the cells in your shoulders, how do they ever get any sugar? Unless the nutrients move into the blood? So because the digestive system is contained within a certain section of your body, if the nutrients never leave the digestive system, they can not be delivered to other cells of the body. But we need to deliver nutrients to all of the cells in the body. And your blood is the only thing that can do that, because you have blood everywhere. Let me show you an image of the circulatory system just quickly to show you where we have blood vessels. So I want one that looks nice and complex. Detailed. So this here is a good example of your blood, okay? So notice how your blood is literally everywhere, okay? So all of those lines that you can see on that man right there, I will take this image into our into our document. But all of the lines that you can see there, that is the blood, okay? We have blood all throughout our body, but we only have the digestive system in a small part of the body. So I'll just put here human blood vessels, just so we know what it is that we're looking at. So the human blood vessels are everywhere, okay? So as soon as nutrients get into the blood, they can deliver those nutrients all around the body. They can deliver them to your feet, to your hands, to your brain, to your liver, to your heart, to all of your muscles. And that's really, really, really, really, really important, whereas the digestive system is just here, okay? So that would mean that the nutrients were stuck in that part of the body. So it's really, really important to get those nutrients into the blood so that they can then be delivered around the body. Now this here is what the human digestive system looks like, okay? It consists of quite a few organs. And you can see we've got the mouth, the esophagus, the stomach, the small intestine, the large intestine, rectum and anus at the end. And then we have some others on there. We've got the liver, the gallbladder, the pancreas and the appendix as well. Now I'm gonna to put a little star next to some of the organs and we're gonna to talk about these first, and I will tell you why in a second. So the mouth, the esophagus, the stomach, the small intestine, the large intestine, and then rectuanus. So the ones with a blue star, our food actually passes through here. So food physically moves through these organs. Okay? So food physically moves through these organs. So food goes into your mouth, it goes down your esophagus, it goes into your stomach. It goes into your small intestine and into your large intestine. Food does not go into your liver. It doesn't go into your pancreas. But those organs help with digestion. That's why they're considered to be part of the digestive system. So let's talk through these one by one. Okay, we're just going to talk about the ones with the blue stars, first of all. Now Isabell, I'm going to talk through them and then I will type in later and I will give you the note just so we can get through them. So first of all, when food enters your mouth, what do you do with food in your mouth? What happens to food whilst it's in your mouth? Cool. You chew it. Well done. And what do you think the point is of that? Who? To make the food very small and you can go down. Well done. So the first thing that we do in our mouths is what we call mechanical digestion. We use our teeth and we rip the food apart, and we make the food smaller so that when it passes into our throat, it can go down into the esophagus. The second thing that we do in our mouths is we mix food with saliva. Now obviously, we don't really realize that we're doing this, but when we're eating, we have that liquid in our mouths, saliva, and that saliva mixes with the food and it makes it softer. It turns it into a bit of a mushy texture, again, so that it can move easily through the digestive system. Because what we don't want is solid food moving through the digestive system because it could get, it could cause choking, it could cause blockage. Okay, so well done. That's the first thing the mouth bites food and Cheit in the saliva. We also have enzymes or an enzyme. Do you remember, Isabella? What did I say that enzymes do? Why are enzymes important to us in biology? I forgot, that's okay. So enzymes are like our tiny little helpers. So they are little chemicals, little molecules that speed up chemical reactions. So we would have enzymes for all sorts of food. We would have starch enzymes, protein enzymes, and fat enzymes. So starch enzymes help to break down starch and they turn it into sugar, simple sugar. Protein enzymes help to break down protein and they turn it into amino acids. Fat enzymes help to break down fat and they turn it into fatty acids and glycerol. So your enzymes help chemical reactions happen. Okay? Really, really important little molecules. You do have some enzymes in your saliva, specifically you have starch enzymes. So next time you're eating a piece of bread, okay, what I want you to do is chew it longer than you usually would, okay? So keep it in your mouth longer, because usually with bread we chew it and we eat it quite quickly, right? We swallow it quite quickly. If you keep the bread in your mouth for a little bit longer than you usually would, that bread will start to taste sweet. So the reason that's happening is because the longer you leave it in your mouth, it's being turned into sugar because you have enzymes in your saliva. And if you keep it in your mouth, you can taste that sugar because we have taste buds on our tongues. So next time you eat a piece of bread, just try it. Just keep it in your mouth longer than you normally would. Just keep chewing it even when it feels uncomfortable, and it will start to taste sweet because it's being turned into sugar. So that's what happens in the mouth of two things. We make the food smaller using the teeth, and we actually start to use chemicals, enzymes from the saliva to break starch down into sugar. Then we have the esophagus, which is this long tube. Okay? So this tube is the esophagus. Now really, the esophagus connects your mouth to the rest of your digestive system, because what you can see is the mouth is up here, but the rest of the digestive system is down here, right? So the mouth is here. The digestive system is here. So what connects the tomb is the esophagus. So the esophagus is the pathway that your food travels down to get to your stomach. It's this long pipe here in your neck and down into your sort of abdomen area or further your chest dish area where your stomach is. And then we get to your stomach. Okay? So the food passes down your esophagus and into your stomach. Now, is there anything that you know about the stomach, Isabella, or anything that you can tell me? What does the stomach do? Is there anything special about the stomach? What's inside the stomach? Say that again, nothing inside. Okay? There is stuff inside. There is a liquid, actually. So the stomach contains what we call stomach acid. So we have stomach acid in here. Have you ever heard that term? Stomach acid? No, no, what about acid, Isabella? You know, like when I say the word acid, what comes to mind? What is an acid? Or what do you know about acids? I don't know about acid, okay? Acids are a certain type of solution, okay? So in chemistry, most solutions are, well, all solutions are either acid, alkali or neutral. Now, an acid is something that can be quite harmful. Not all acids. It would have to be a strong acid. So if you got acid on your skin, it would burn you. It would cause damage to the skin cells. So inside our stomach, Interestingly, we have this this harmful liquid, and that's where it starts to get a little bit you know confusing, because how have we got this harmful liquid in our stomachs? But it doesn't harm us because the acid doesn't hurt us. As long as we're healthy and we don't have too much acid and the stomach is all intact, it doesn't harm us. Actually, it helps. So the acid is a harmful liquid inside the stomach. The reason that that acid is there or the role that it plays in this particular incident is that it kills bacteria. So if you eat something and it has bacteria on it, usually you'll be okay as long as it's not too much bacteria. It's a small amount of bacteria and it's not you know an extremely harmful bacteria. When you eat it, the food goes down into the stomach and the acid kills bacteria, so it stops bacteria from harming you. So this part of your digestive system is almost like a preventative section. It helps to keep you safe even if you eat something that could possibly harm you. So in the stomach, we have stomach acid. That's a liquid that's always there. Isabella, have you ever eaten something and you feel really full? And afterwards you have pain in your chest. You have like a, it's hurts, it's painful in your chest. No no I. Think, youknow, what I was talking about if you did. So what I'm referring to there is what we call indigestion, which is where sometimes a small amount of the acid from the stomach might come back up here because the stomach is too full. And if that happens, the person starts to feel pain because the stomach acid is hurting the esophagus. Okay? This doesn't happen often. So only if you eat way too much or if the stomach makes too much acid. But it doesn't happen often. But if it does, you'll know about it because it becomes painful. So the stomach contains stomach acid that kills bacteria in your food. It also helps to mix the food together and it makes it even smaller and it starts to turn it into a solution even further. So that's what the stomach does. Your stomach also stores your food for a little while. Okay? So when you eat, your food might stay in your stomach for an hour or two hours even, and it stays there until the rest of the digestive system is ready to take this food. Okay? The next thing is the small intesty. So that's this here. You ready? So where my line is, this whole thing is the small intestine. It's not very well named because the small intestine is a very big structure, okay? It's very, very, very long and it's all curled up inside that part of the body. So your small intestines are where generally people think that their stomach is. So if you have a look here, this man's stomach is just here in his, like this area here, I don't know if you can see me, I'm probably too high. This area here is where your stomach is right below your armpit here. Okay, so your stomach is more further up the body than you think it is where your lower abdomen is. So usually where people think the stomach is, that is actually your intestines, your small intestine, and your large intestine. And they are all long coils of muscular tubes all coiled up within that abdomen space. Now the small intestine is a really, really important part of the digestive system. This is where the food stays for the longest period of time. Your food might stay in your small intestine for anywhere between four and maybe even eight hours. Okay? So food stays in there for a long time. It's in there for a while. And whilst it's in there, the role of the small intestine is to break it all down as much as possible. We really want to try and get as much nutrients as we can out of food because Isabella, let's say you have your breakfast. Okay, what do you usually eat for breakfast? Chinese妮。Dumplings, okay, so that would be quite carbohydrate rich, right? So you would have, if you eat in the morning, if that, if your body then breaks that down into sugar and you will use that sugar as energy throughout the day. So what your body wants to do is when you eat your breakfast dumplings, let's say when you eat it, your body wants to make sure that it breaks the whole thing down into sugar, because your body doesn't know when you're next going to eat. So we need to get as much nutrients as we can out of your food. The body tries its very best, and it's absolute hardest to try and get the most out of what you eat, tries to absorb as much energy and as much nutrients as it can from your food, because let's say you didn't eat then until nitime, that food that you ate for breakfast has got to last you all day. Your body's got to use that food, those nutrients all day. So your digestive system is really, really efficient. It's really good at breaking down food into as many nutrients as it can. Now it's not 100% efficient. We never digest 100% of our food because there is always waste at the end. We're not 100% efficient, but we are very good. So in the small intestine, whilst your food is in there for four, five, six hours, it gets broken down as much as it possibly can, and we move those nutrients into the blood. So the small intestine is really where most of the digestion happens. So in the small intestine, we will have all of the enzymes that we need. We will have enzymes for carbohydrates, enzymes for proteins, and enzymes for fats or lipids as well. The small intestine is also where the nutrients then move into the blood. Okay? So at the start of the small intestine, when the food first goes in, the enzymes break it down into small, small, small pieces. Then towards the end, once we've broken all of the food down or as much of the food that we can, those nutrients then move into the blood. Remember, Isabella, why did we say it's important that the nutrients move into the blood? Else. And things cannot use. So what can the blood do with the nutrients? Go in together. Yeah, definitely. And where can your blood deliver the nutrients? Where does it deliver them everywhere? Well done. Exactly. It delivers them everywhere. And that's the important thing. If we want to get those nutrients around the body, we have to make sure that they move in the blood. Okay, excellent. Well remembered. And then finally we have the large intestine. Okay, so the large intestine is here. So even though it's called the large intestine, it's actually the smaller one. The reason it's called the large intestine, though it's not accidentally named, the reason it is called the large intestine is because it's wider, it's thicker. Even though it's shorter, it is thicker. As you can see, it looks bigger, right? So here is the large intestine. There we go. And it reaches to the end of the body. Now the large intestine is where waste product is made. So human thees that gets removed from the body is made in the large intestine. So if you think about it, when we've passed this food through our body, in the mouth, we mixed the food with saliva. In the stomach, we mixed the food with stomach acid. In the intestines, we mixed the food with enzymes. Now by this point, the food is very watery. It's like a liquid. So we don't want to lose all of that liquid from the body, because if we move all of that liquid out of the body, we will get dehydration. So whilst this liquid is moving through the small intestine, so whilst it moves up here, the small intestine takes water back out, okay? So it pulls water from the mixture and moves that water back into the blood. So what we're left with by the end, by the time we reach the end of the digestive system is a solid waste product known as feces, which is waste. The person then goes to the bathroom, they remove this from their bodies, and then we can eat again. Okay? So that's how the digestive system works. So the food goes, mouth, esophagus, stomach, small intestine, large intestine, and then it leaves the body as a waste product, okay? And then that's the end. That's the end of the the process. So that is our organs that actually PaaS the food through. So all of these here, the small intestine, the rectum and the anus. So they are this part of the body that's just where the waste product is stored at the end. So whilst the person is waiting to go to the bathroom, the waste product is stored at the very, very end of the small intestine which is here. And then anus is just how it's removed from the body. So that's the exit point, okay? That's how theses leaves the body. So these parts are the right at the end of the large intestine. Now there are some other organs here and I'll put a Red Cross next to them. So we've got the liver, we've got the gallbladder, we've got the pancreas, we've got the salivory glands and we've got the appendix. Now we kind of briefly talked about the salivary glands, but it's important. The ones with the blue stars, the food actually touches those organs. The ones with the red stars, we call these helper organs, the food doesn't actually touch your salivory glands because in your mouth, well, in your head, your salivary glands are back here. Okay, so theybe here. Now your mouth stops here. So the food doesn't go back into my salivary glands. Food is in my mouth and it does not go further back. My salivory glands, though, put saliva into my mouth. So even though the salivary glands help, they don't actually touch the food. Okay? So these red organs, they don't touch the food. So these are accessory organs, we call them. So these are accessory organs. These organs help with digestion, but the food doesn't PaaS through them, so these organs help with digestion. But the food does not PaaS through them, okay? And that is important. The food does not PaaS through them. Okay, so the salivary glands is the first one. The liver is another one. Now your liver is above your stomach, okay? Your liver doesn't PaaS the food through. The food doesn't go through your liver, but your liver produces something called bile. Now, have you ever heard of bile before, Isabella? Have you ever heard that word before? No. So bile is a liquid. Okay? And do you remember me saying that in the stomach we have stomach acid that is harmful to us? Yeah. Now that's fine. The stomach acid staying in the stomach is fine because the stomach has a layer of protection which allows it to hold this acid without getting damaged. So in the stomach, there is a special structure that allows the acid to stay there without damaging the stomach. However, that is not anywhere else in the body. So if the stomach acid comes out of the stomach, it can cause damage. Like I said, remember when I said, if your stomach acid ever comes up, it causes pain in this area. If the stomach acid was to ever go down, it would cause pain in that area as well. So the stomach acid has to stay in the stomach. It can't come out either side. It can't go up or down. If it does, it will cause damage. However, the food has been in the stomach acid, right? And it's going to come out of the stomach and go into the intestines. Now bile is then added to to the small intestine. And when bile and acid mixed together, they make water. Okay, so bile plus acid, bile plus stomach acid make water. And I will talk to you more about this a little bit later on as to why. But when bile and stomach acid mix together, they make water. So if stomach acid does come out of the stomach, it mixes with bile straight away and it turns into water, and then that's safe to move through the digestive system. Okay, so I'll zoom in here. This here is the end of the stomach. So this here is the end of the stomach. So when food comes out of the stomach, it's entering into the intestines. So these are the intestines, okay? When it leaves the stomach, the food will have acid in it or around it. It's mixed with acid because it's been in the stomach. But here we have bile put into the small intestine by the liver. So the liver makes bile and it puts that bile into the small intestine. So as soon as the food leaves the stomach here, it mixes with bile. So straight away we turn that acid into water. And that means that that water can then move all the way through the small intestines and it doesn't cause any damage. Okay? So water is fine. Of course water is fine. Water is healthy for us. Yeah. But acid isn't. So the main thing that the liver does is it turns that harmful acid into water so that solution can move through the digestive system safely. Okay. Does that make sense? How I've explained it? Yeah. Are you sure any questions you want to ask? I what. The acid gets turned into water. So when we mix it with bile, it turns into water. Yeah. So it goes from acid, which is harmful to water, which is fine. And that's why we mix it with bile. That's why the liver is important. That's how the liver helps. So the acid comes out of the stomach. The liver mixes bile with the acid together. It turns into water. And now it's safe to PaaS through the small intestine. Yeah. Does that make sense? You sure. Okay. Then we have the pancreas. So this word, the pancreas. Now the pancreas is this tiny little organ. This here is the pancreas. Okay? There it is. It's only small. It's right underneath the stomach. Now the pancreas makes enzymes. Okay? So the pancreas makes enzymes. What did we say enzymes do again? That. So good. Yeah, one of them turns starch into sugar. Well done. They speed up. What do they speed up? Enzymes speed up. And. They turn big molecules into. Well done. Yeah. Well done. So enzymes speed up chemical reactions. These ones that we're talking about, our digestive enzymes, they turn big molecules into small molecules. Okay, well done. So they break starch down into glucose, protein down into amino acids, or fats down into fat, fatty acid and glycerol. Okay, great work. Well done. So protein, sorry, enzymes speed up chemical reactions. So your pancreas makes those enzymes. It's like the factory for enzymes. It's the enzyme factory, okay? So in that little organ there, all of the enzymes that we would ever need for digestion are inside. So we have enzymes for carbohydrate, enzymes for starch, enzymes for protein, and also enzymes for fat. We have all of the enzymes that we would need, and they are made here. And then the pancreas puts those enzymes into the small intestine so that the small intestine can break down as much of our food as possible. So those enzymes are made by the pancreas, and they're used in the small intestine. And then finally, we have the appendix. Now, Interestingly, we actually don't need our appendix anymore. You can live without your appendix. We think that the reason we have an appendix is when we were millions of years ago, before we evolved into humans, that we are now, we used to eat more grass, like like cows do, okay? We used to eat more grass, more vegetables, and we think that the appendix was involved in breaking down grass, basically, not just grass, but other vegetables and plant ants. So when our diet was mostly plant based millions of years ago, we think that's what the appendix was for. Now, we don't use the appendix very much at all. Okay? So even though it's there, we don't really use it as humans, okay? We can live without our appendix. We don't really need it. So the main organs that we've got there, our mouth, our esophagus, our stomach, our large intestine and our small intestine, and then our salivory glands in our mouth, the liver, the sorry, the pancreaas, and then that's it. There are main organs. They're the ones that we use for digestion. So remember, the main goal of digestion is to take large molecules and turn them into much, much smaller ones so that they can move into the blood. Why was it important, Isabella, one more time? Why is it important to move those molecules into the blood? Us the can go to everywhere. Well done. Because the blood can deliver those nutrients all around the body. Okay? So when we eat, our digestive system makes the food smaller. Those small molecules then move into the blood. The blood delivers them to the cells. And that's how what we eat ends up in our cells. Okay, well done. A lot of information there. I'll send the note a bit later, Isabella, because I need to top it off, I need to type in all of the definitions and what each of the organs do and then I'll send it to you. But well done. Tomorrow we'll be doing chemistry. So we will Yeah, we'll be doing chemistry. I'll have a look at our notes and see where we've got to and what we'll be doing tomorrow. Okay, so well done. Have a lovely evening and I will see you tomorrow. Okay. Okay, see you tomorrow, okay, bye bye bye bye bye.