Lesson video

- Hi everybody! It's Mrs. Buckle back again to teach you some science.

I'm really excited about today's lesson.

We're going to be looking about how organisms are organised and what actually makes up a living thing.

For today's lesson, all you are going to need is somewhere to write down your ideas, be that in a notebook and a pen, or a digital device if you are willing to use a laptop or a tablet or your mobile phone or something along those lines, and obviously your brains as well.

Let's get those engaged before we start.

The title of today's lesson is "Organisation", and this fits within our Cells Unit, within Science.

An overview of what we're going to be learning today: We are going to describe how multicellular organisms are arranged into tissues, organs, and organ systems. Okay, before we get started, let's just have a look at some of the keywords we are going to be using today.

The first keyword I want us to be aware of is organism.

We're gonna be using this word organism a lot, and you will have heard it before within this unit.

Remember, an organism is just a living thing.

So I'm an organism, you are an organism.

Plants, animals, fungi, bacteria, all of those things are organisms because they are alive.

The second keyword is cell.

A cell is the smallest unit of living things.

So that's what we're going to be talking about today.

When we're referencing a cell, we are referencing the smallest unit of an organism.

The next one is hierarchy.

A hierarchy is just a way to organise something.

It's a list that goes in order of preference, or seniority, or size.

And today we're going to be looking at the hierarchy of parts of living things.

How do we organise what makes up a living thing? Our three learning outlines today are to describe what a tissue is, to describe what an organ is, and to describe what an organ system is.

Now all of these things make up an organism, but we're going to start with the smallest and we're gonna have a look at tissues.

So let's start by remembering that organisms can be unicellular or multicellular.

A unicellular organism, like the one on your screen, this example is a bacteria actually, are made of one cell and one cell only.

All of the living processes that the organism needs to do takes place in that one cell.

And these cells are normally specialised to be able to move and do other things so that the entirety of the living processes can take place in this very small cell.

Whereas a multicellular organism, such as an animal or a plant, they are made of multiple cells.

They are made of more than one cells, and all of those cells within a multicellular organism work together to carry out the living processes of that organism.

So unicellular is an organism that is made of one cell, and multicellular are organisms that are made of more than one cell, or multiple cells.

Today we're just going to focus on multicellular organisms. So we've already said that multicellular organisms are made of more than one type of cell, and they are actually made of different types of cells.

So within different parts of a multicellular organism, you will find different cells.

How many cells do you think a human being is made of? I know that a human being is a multicellular organism, and I know that that means they are made of more than one cell.

But how many cells do you think needs to make up a human? Think about your answer and come back to me when you are ready to find out.

Okay, I bet you've come up with some great ideas.

The actual answer is 37.

2 trillion, which is just a humongous number, cells.

So one human being is made of not just more than one cell, but actually 37.

2 trillion cells.

And within that 37.

2 trillion cells, there will be lots of different cells working together to carry out the living processes.

We are gonna have cells in our brain that are completely different to the cells in our skin, that are completely different to the cells in our stomach, and so on and so on and so on and so on.

The same thing would happen in a dog or a plant.

They're gonna have different cells and they're gonna work together to carry out the living processes of that organism.

The cells in multicellular organisms are arranged in a hierarchy, in an order.

I want to look at an example of a model here.

Just like bricks, when we work with bricks and we add lots of bricks together, we can make a wall.

And if I have lots of walls, I could make a room, such as a kitchen.

And if I had lots of rooms, like a kitchen and a living room and a bedroom and a bathroom, I could make a house.

I could say that this is the hierarchy of the functional parts of a house.

The smallest unit of a house is a brick.

Lots of bricks work together to create walls.

Lots of walls working together create a room.

And when I have lots of rooms doing different jobs, I have a house.

The same model can be applied to a multicellular organism.

We start with cells.

Lots of cells working together can make a tissue.

Lots of tissues working together make organs.

Lots of organs working together make an organ system.

And lots of organ systems, when they work together, create an organism.

Now in this example, I've got a human being.

So I've got an animal cell.

Lots of animal cells making muscular tissue.

Lots of tissue such as muscle, connective tissue, and nervous tissue, making an organ, such as the heart.

Lots of organs, such as the heart, veins, arteries, capillaries, making the organ system, the circulatory system.

And lots of those systems, such as the circulatory system, the gas exchange system, the digestive system, they will work together to allow for an organism to carry out its living functions.

In this case, the organism is the human.

We can see we have a hierarchy, because we are starting with the smallest unit of this organism, a cell, and we are seeing how each part of the hierarchy works together to make the next largest unit.

Cells make tissues.

Tissues make organs.

Organs make organ systems. And organ systems work together within an organism.

Let's do some Check for Understanding questions now.

I'm going to read the question.

I want you to pause, choose your answer, and come back when you are ready to check if it's right.

Question one: Which two are examples of multicellular organisms? Fantastic if you said "human" and "rose bush".

A human is an example of an animal, and a rose bush is an example of a plant.

Animals and plants are multicellular organisms. A bacteria is only made of one cell, so that is a unicellular organism.

Question two: What is the smallest unit of living things? Well done if you said "cells".

Cells are the smallest unit of living things and they come first in our hierarchy.

Next question is a true or false.

True or false: All organisms are made from organ systems. Okay, the answer was "False".

I want you to have a go now at justifying this.

Is it because not all organisms have the same organ systems, or is it because only multicellular organs are made from organ systems? Brilliant.

It was B, only multicellular organisms are made from organ systems. Some organisms are unicellular, and they do not contain organ systems. So how do tissues fit in to our cell hierarchy? Well, let's just have a quick recap.

Remember that cells are the smallest unit of living things, and that tissues are made of cells.

Each organ is made of different tissues working together.

So tissues fall in-between cells and organs.

Tissues are made of cells, and organs are made of tissues.

In this example, I have animal cells at the start.

Lots of animal cells working together create the tissue, muscle.

And within the organ, the heart, one example of a tissue that makes up that organ is muscle tissue.

So the heart is an organ and it is made up of different tissues.

On your screen, you should be able to see a picture of a human heart.

The tissues that make up the heart are cardiac muscle, connective tissue, nervous tissue, and epidermal tissue, which is a type of connective tissue.

Each one of those tissues carries out a particular function that allows the heart to pump blood.

For example, the cardiac muscle contracts and relaxes, and that allows the heart to push blood out of its chambers.

The connective tissue keeps everything held in place.

The nervous tissue receives signals from the brain to allow us to adapt that heart rate, that pumping and relaxing, and the epidermal tissue protects everything within it and acts as a capsule.

Humans aren't the only thing with tissues.

Let's have a look at this.

These are actually cells inside of a leaf.

A leaf is an organ found within plants.

The leaf is an organ because it is made up of lots of different tissues working together.

For example, the dermal tissue at the top of the leaf; the palisade tissue within the centre of the leaf; we've got a vascular bundle, which we can see is a kind of tube that runs through the leaf; and we also have a mesophyll layer.

All of these layers of tissues work together so that the leaf is able to carry out its function.

A leaf is an organ in a plant because it is made of different tissues.

Here is a picture on your screen.

What type of tissue could this be, and why? Pause the video and come back when you are ready to share your ideas.

Okay, welcome back.

I left a few clues in this image, this micrograph, for you to be able to figure this out.

So I gave you the colour and I also gave you the shape of the cells.

This is actually the dermal tissue of a leaf, and I know that because it's made of plant cells and I can see that because they are rectangular in shape, and if I look really closely, I can also see the cell membrane and cell wall.

I know that this is a tissue because there are lots of cells within this micrograph, and I am assuming they are working together.

So this must be a tissue within a plant, and it's actually the dermal tissue of a leaf, so the top layer of a leaf.

Okay, a couple of Check for Understanding questions about tissues.

Again, I will read the question.

You need to pick your answer and once you're ready for it to be checked, un-pause the video and come back to me.

Which image shows a tissue? Hopefully you said "B".

A is a heart, and C are lungs.

Those are both examples of organs, so the tissue is the one in the middle, and we can see we've got lots of cells in there working together.

What are tissues made of? Hopefully you said, "cells".

Well done.

Remember, tissues are made of cells, and lots of cells working together makes a tissue.

Okay, here's our first task of today's lesson.

What I would like you to do is identify if the statements are true or false and tick the correct box in the table.

I would then like you to explain why the false statement is incorrect.

So there is more than one false statement.

Once you find a false statement, I want you to explain why it's wrong.

This should take you 5 to 10 minutes.

Make sure you try your best at it.

If you need to rewind or go back over some content, absolutely fine.

Once you are ready to go through your answers and do some self-assessment, resume the video and come back to me and I will go through them.

For now, pause the video and have a go.

Okay, let's go through these answers.

The first statement was, "Tissues are only found in animals." This is a false statement.

Statement number two: "Cardiac tissue is an example of a tissue." This is a true statement.

We looked at cardiac tissue when we were talking about the heart.

Statement three: "Leaves are organs." This is also a true statement.

We looked at an image of leaf and we saw all the tissues working together.

Statement number four: "Each tissue is made of five cells." That is a false statement.

Statement number five: "Cells work together to carry out functions." That is a true statement.

Cells work together in tissues to carry out the function of the tissue.

Remember, function just means job.

And statement number six: "There is only one type of cell in the heart." This is a false statement.

Right, let's have a look at explaining why those three false statements are false.

Statement one is false, as all multicellular organisms have tissues and plants are another example of a multicellular organ.

Statement four was false because tissues are made of much higher numbers of cells.

Remember when we looked at those tissues, there were were lots more than five working together.

And statement six is false because the heart is an organ which is made of different tissues.

Each of those tissues will be made of different cells.

So the connective tissue will be made of different cells to the cardiac muscle tissue, and therefore there are more than one type of cell within the heart.

Really well done, especially if you've got those explanations right.

Those were tricky.

I tried my best to challenge you.

So if you got those correct, be really, really proud of yourself.

So far today, we have described tissues.

We are now going to move on and look at describing an organ.

There are a total of 78 organs in the human body.

Hopefully you've come across some of these before.

We've come across at least two today, in this lesson.

I want you to spend two or three minutes.

If you're on your own, jot these answers down.

If you're with someone else, you might want to discuss your ideas with them.

See if you can get as many as you can.

I only want you to spend a maximum of three minutes on this task.

So set yourself a little timer, three minutes.

And once you are ready to pause the video and go, start your timer, and write a list of as many organs as you can.

See how close to 78 you can get.

Ready? Pause the video.

Off you go! Woo! Welcome back! Hopefully you've got a really long list.

I could not fit 78 on my screen, so I've gone with some of the important ones.

So we've got kidneys, lungs, and the stomach.

Really different organs here.

So kidneys, they come in pairs.

They are located at the bottom of your back.

Lungs are in your chest, again in pairs.

Hmm, pairs again.

They're involved in our breathing.

And stomach, obviously within the digestive system within our abdomen.

Really odd shape, yeah.

But it's red because made of lots of muscles.

When your tummy gurgles, it's all these muscles contracting.

So three examples of organs there.

Hopefully you've got much more than three.

If you are interested in checking your list, I'm sure you'd be able to find one on the internet and see how many organs you've got correct.

Remember from our cell hierarchy, we said that organs are made of different tissues.

So within the kidneys, we're gonna have different tissues working together.

In the lungs, different tissues working together.

And in the stomach, even though it doesn't look like it, there are definitely lots of different tissues working together to carry out the function of the stomach.

Each organ carries out a specific function within a system.

So all three of these organs are within different organ systems. The kidneys are in the excretory system and they work really hard with lots of blood vessels and with your bladder to create urine.

And the lungs are in the gas exchange system.

So they're working at taking all the good stuff out of the air that we need in our body, and also getting rid of any waste gases within our body.

And the stomach is involved within the digestive system, so that helps us to break down food and get the nutrients that we need.

They all have a different function because the organ systems that they're a part of do a different job.

So, let's take a look at one of these systems. We've got the digestive system on your screen, a nice lovely diagram of the digestive system.

We can see it's made of lots of different organs and each one of these organs is gonna have a different function.

All of those organs are working together to carry out the function of the digestive system, which is to take nutrients out of our food, get them into our blood, and get rid of any waste.

We're gonna look at four organs of the digestive system and talk about each one of their functions.

The first organ is the stomach, and then we've got the small intestine, the large intestine, and the liver.

Four quite large organs, actually, within this system.

Again, they are all working really, really hard to help us take nutrients out of our food and get rid of waste, but they each have their own part to play within this system.

The stomach digests food, okay? So it takes these large pieces of food and makes them much smaller, using a mixture of chemicals and muscle contraction to get those food into smaller molecules.

The food is then passed down to the small intestine, and in the small intestine all the nutrients that we would want from that food, so our vitamins, our minerals, proteins, carbohydrates, lipids, all those things from our food that our body needs is taken out of the food and is transferred into the blood.

So the small intestine absorbs the nutrients from the food.

The large intestine actually takes out water.

So water is one of the seven nutrient groups and it is found in food, and we need that water to be able to make sure our cells are working perfectly all throughout our body.

So the large intestine takes out any water from the food that we need.

The liver isn't actually directly connected to the small intestine and the large intestine, but it carries out a secondary job.

So the liver produces a substance called bile.

Bile contains enzymes, which are biological molecules that help in digestion.

So they help to absorb the nutrients and absorb the water, because they support the stomach in digestion.

So the bile actually leaves the liver and enters into the intestines and it helps with that digestion further on.

We can see that each four of these organs carry out a different function within the organ system, but all of them are working together to help to digest the food that we take into our bodies.

There's another system here.

Let's have a look at this.

This is the respiratory system, or the gas exchange system.

This system has different organs and it also has a different function.

So the respiratory system's function is to take oxygen out of the air and take it into our blood, and it's to take carbon dioxide from our blood and allow us to exhale it back into the air.

It's a waste product.

This organ system is made of different organs.

We've got a lung, diaphragm, trachea, and we've also got the nose.

Each one of these organs carries out a different function.

Have you, have a think, looking at these organs and where they are, what the functions, the job of these organs, might be? Pause the video and resume when you are ready to find out the answers.

Welcome back! Let's have a look then and check your answers as we're going through, 'cause I bet you were right about some of them.

So the lungs are where gas exchange takes place.

We've got two lungs, we've got one pointed to in our diagram.

So that's where oxygen is taken into the blood and carbon dioxide is taken out of the blood.

Gas exchange: Oxygen in, carbon dioxide out.

Swaps.

The diaphragm hiccup.

So when we hiccup, we are contracting our diaphragm too much or too quickly, and that helps us with inhalation, breathing in, and exhalation, breathing out.

So when you breathe in, your diaphragm moves downwards to make that space in our lungs much, much bigger and allow more gases to enter the lungs.

And when we breathe out, our diaphragm moves up, makes this space smaller, and gas is pushed out of our lungs.

So it's a muscle that contracts and relaxes to help us inhale and exhale gases from our lungs.

The trachea, also called windpipe by some people, is literally what it says on the tin.

It is a pipe that connects our mouth and our nose to our lungs.

So that's where the air moves down into the lungs, or moves out from the lungs to the mouth.

It's just a tube that goes from the mouth to the lungs.

And finally, the nose is actually where most of the air that we inhale moves into.

You can see that it's quite a large space compared to the space within the mouth, and air can move into the nose and then it will be passed down the trachea and into the lungs.

So again, we've got four very different organs doing four very different functions, but all working together to allow oxygen to move into our blood and carbon dioxide to be taken out of the body.

Okay, some quick Check for Understanding questions then.

So again, I will read the question.

You have a think about your answer.

Once you have picked it, resume the video and check if you are right.

So what are different organs made of? So, what are organs made of? Fantastic if you said, "different tissues", well done.

Which is not an organ in the digestive system? Hopefully you said, "heart".

Well done.

The liver and the stomach are found in the digestive system, but the heart is not.

What is the function of the lungs in the respiratory system? Tricky one, this.

Well done if you said "gas exchange", where oxygen's taken into the blood and carbon dioxide is taken out of the blood.

That moves us nicely onto task two for today's lesson.

What I would like you to do is first of all, sort the organs into the correct organ system.

So all of those organs underneath are either part of the digestive system or the respiratory system, and it's your job to figure out which one's which.

And then for question two, I would like you to explain why the heart is an example of an organ.

Pause the video, take your time with it.

Once you're ready to check your answers, come back and we will go through them.

Off you go! Okay, let's go through the answers then.

So in the digestive system, hopefully we've got the large intestine, the liver, the small intestine, and the stomach.

And in the respiratory system, we should have had diaphragm, lung, nose, and trachea.

Make sure your ticked are corrected.

And then question B, "Explain why the heart is an organ." The heart is an organ because it's made of different, that's important, make sure you've talked about different, different tissues and carries out a particular function within its organ system, the circulatory system.

Two key things there, I want you to see you talking about different tissues, and the fact that it carries out a particular function within its organ system.

Okay, so far we've described tissues and we've described organs.

Let's finish off today's lesson by looking at what an organ system is.

So let's just recap.

Looking at our cell hierarchy diagram, a multicellular organism is made of organ systems working together.

So if we start at the very beginning with the smallest, we've got cells, lots of cells working together make tissues, lots of tissues working together make organs, lots of organs working together make an organ system, and lots of different systems working together make an organism.

An organ system is made of organs working together.

What are some examples of organ systems? We've looked at two.

There is a picture of another one on your screen and there may be a few more that you've heard of before.

Pause the video, write down some ideas, and come back to me once you are ready to share.

Welcome back.

Oh, wonder what we've come up with.

So we've got the digestive system and the respiratory system, which we've just looked at in task two.

We've got the circulatory system, which is on the screen.

You might have talked about the nervous system, the reproductive system, the excretory system.

There's lots and lots of systems within a human body.

Let's have a look at some images.

So we've got four images here.

Can you figure out what they are? Whoa, I'm not sure.

Let's have a look.

So the first one is the circulatory system.

We can see we've got the heart in the middle of that and then we've got all of those blood vessels coming away from it.

We've got the digestive system, which we've just looked at in task two, as well as the respiratory system, which again, we've just covered in task two.

And the final one on your screen is the skeletal system, which is made of all the bones and ligaments and joints within the body that work together to help us move.

So four systems there, but we can see within each system, we've got different organs working together, and we know that each system also carries out a particular function.

Let's have a look in a bit more detail in the circulatory system.

So the circulatory system is an example of an organ system.

Can you name any organs that make up the circulatory system? We've mentioned a few already.

Write down some ideas.

Resume the video once you are confident.

Okay, let's see if you've got these.

It's made of the heart and it's made of blood vessels.

You might have put arteries, veins, capillaries; those are examples of blood vessels.

All of those things work together to be able to get blood to move around the body, which is the function of the circulatory system.

Here we've got the digestive system and it's another example of an organ system.

Now we've just done this, so I know you know some of these.

Which organs make up the digestive system? Resume once you are ready and you are confident.

Stomach, did you get stomach? Hopefully so.

Liver, small intestine, large intestine.

You might have also put things like the pancreas.

There are a couple more in there.

Maybe you might name some different parts of the large intestine.

Maybe you've talked about the oesophagus, there's a couple.

So again, all of those organs working together to carry out the function of the digestive system, which is to get nutrients out of our food and get rid of any waste.

Okay, let's do some Check for Understanding questions about organ systems. Question one: What are multicellular organisms made from? Hopefully you said "organ systems".

Well done.

Next one: What are organ systems made of? Well done if you said "organs".

And that takes us nicely to task three.

So for task three today, what I would like you to do is order the following into our cell hierarchy diagram.

So starting with the smallest and move all the way up to the largest, put those key turns into the hierarchy.

And then task B: Explain, so giving a reason why, explain why the digestive system is an example of an organ system.

Try your absolute best with this.

Let's finish on a positive.

Pause the video now, and resume when you are ready to go through the answers.

Okay, let's start with the cell hierarchy diagram.

So start with the smallest, that's a cell.

Lots of cells make tissue.

Lots of tissues make an organ.

Lots of organs make an organ system.

And lots of organ systems make an organism.

Well done if you got all of those.

It can be quite confusing, especially in the middle.

If not, don't worry; just make some corrections.

And in task B: "Explain why the digestive system is an example of an organ system." It is an example of an organ system because it's made of lots of different organs such as the stomach, or you might have given a different example.

So the idea that it's an organ system because it's made of lots of organs.

Okay, task C: You're going to take that knowledge of organ systems and what I would like you to do is tell me the function, so remember that means job, of the system and as many organs as you can think that organ system contains.

Now there are two organ systems I want you to do this for: the skeletal system and the nervous system.

This is quite tricky, but I know you can do it, definitely.

So give it a really good go.

Pause the video, and then resume once you're ready to go through it.

Okay, off you go.

Okay, let's go through the answers.

The skeletal system, we saw a picture of it earlier.

It's essentially the skeleton, isn't it? But it's actually made of lots of different things.

So, the function of the skeletal system, it gives the body its shape or it allows movement.

It also makes blood cells and provides protection for the organs.

So if you think about the skull, the skull protects the brain.

Or the ribs, the ribs protect the lungs, they provide protection.

And it's made of bones, cartilage, ligaments, and tendons.

Okay, the second system is the nervous system.

The nervous system responds to stimuli, so responds to everything that's going on around us.

It maintains what's happening inside.

It maintains internal conditions.

It controls us, it controls our movement and our memory and our thoughts.

And it's made of the brain, which is in the skull, and the spinal cord as well.

Brilliant.

We've finished! Time flies, right? Let's do a quick summary of what we've learned today about organisation in multicellular organisms. Multicellular organisms are made of structures which are arranged in a hierarchy.

And in that hierarchy, cells are the smallest units.

Our hierarchy looks like this: We start with cells.

Cells make up tissues, tissues make up organs, organs make organ systems, and lots of organ systems make up an organism.

Organ systems work together in an organism, and organ systems are made of organs.

The circulatory system is an example of an organ system.

Each organ within an organ system carries out a particular function, a job, and it is made of different tissues.

An example of a organ that we've looked at today is the heart.

Tissues are made of cells, which work together.

And one example of a tissue that we've looked at today is cardiac muscle.

You've done absolutely brilliantly.

There have been lots of words today that all sound the same: Organ, organism, organ system.

Oh! It's been confusing, but I'm so, so happy that we've got through it and we've got to the end.

And that is it for today's lesson, and I hope to see you soon.

Bye!.