Hello, my name is Mr. Wilshire, and in this lesson, we are going to be looking at the function of blood vessels.

The outcome of our lesson is: I can describe what blood vessels are and what they do.

As always, there are some keywords for us to consider throughout this lesson.

If you need to, you can pause the video here and try and have a recap about what they mean.

But don't worry though, because as we progress through the lesson, the meanings should become clear.

The keywords are: blood vessels, arteries, veins, oxygenated, and deoxygenated.

Pause the video now and have a read if you would like to.

The first part of our lesson is called All about blood vessels.

Aisha and Laura are learning about the function of the heart and the blood in the human body.

Aisha says, "I've learned that the heart pumps blood all around the different parts of my body." And Laura says, "I've learned that blood has many functions.

One of them is to transport oxygen, nutrients, and water around my body." Hmm.

I wonder if you can think of anything else.

Do you know if blood is required to transport anything else? Have a think.

Pause the video now and restart when you've done that.

So what did you think of? Was there anything else that needed to be transported? Well, Aisha says, "Oh yes, blood also transports carbon dioxide back to the lungs, so then it can leave the body.

I wonder how blood transports these substances though." Laura says, "I think the human body is full of blood, and all of these substances are in the blood as it sloshes around throughout the body." Hmm.

Does that sound right? What do you think? Does your blood slosh around in your body? Pause the video now and have a quick discussion.

What did you think of? Does your blood slosh about? Let's find out more.

Well, blood vessels carry blood all around the human body.

It goes to and from the heart.

Aisha says, "A vessel can be a ship or a container for holding liquids.

So does blood float round in little containers?" Not quite, but what do you think? Pause the video and have a quick discussion.

Does our blood float around in a container like that? What does that mean? Blood vessels are actually hollow tubes.

Here is an enlarged drawing of a blood vessel, and you can see some of the components of blood travelling inside.

Now, although this is an enlarged drawing, remember, blood vessels are actually very, very thin and very, very small, and they travel all around your body.

The function of blood vessels is to transport blood to every part of the human body.

Here you can see blood vessels going all around the body there, connecting all sorts of different parts.

Of course, it starts here at the heart and then goes elsewhere.

So if you were to lay all of the blood vessels from an average child end to end, it's estimated that they would stretch for over 60,000 miles.

So that's approximately two and a half times around the Earth.

So from one average child, all the blood vessels inside, if they were stretched out, they would go that far.

That's incredible, isn't it? The blood vessels are very, very important for transporting blood and doing lots of different jobs.

So let's stop and think.

A blood vessel only transports blood to the heart.

Is it true or is it false? The answer here is false.

Blood vessels don't just transport blood to the heart.

How can we justify this answer? The correct answer here is: blood vessels transport blood to and from the heart.

The heart is just a part of the system connected to all the different blood vessels.

Blood needs to be pumped away, and blood needs to be pumped towards the heart as well.

Now, the heart pumps blood around the body through different types of blood vessels.

Laura here says, "Do different blood vessels have different names?" Aisha then says, "I think there are oxygen blood vessels and carbon dioxide blood vessels." Hmm, what do you think? Are they the different names? Do they do different jobs? Have a quick discussion.

Let's move on and find out more.

Arteries are just one type of blood vessel.

The function of most arteries is to deliver blood containing oxygen and nutrients to all the parts of the body.

Izzy says, "Arteries transport blood away from the heart." Blood that is rich in oxygen is called oxygenated blood.

Veins are another type of blood vessel, and they have got a different function.

After the oxygen has been used up by the body, veins transport carbon dioxide back to the heart where blood is then pumped to the lungs to pick up more oxygen and drop off the carbon dioxide so it can be breathed out.

Izzy says, "Veins transport blood back to the heart." Now, most veins carry blood that is low in oxygen.

This is called deoxygenated blood.

So let's stop and think.

Which two of the following statements are true? Read the statements and decide.

The answers here are A and B.

Veins and arteries are types of blood vessel, and most veins return blood low in oxygen to the heart.

Stop and think again.

The blood in most arteries is.

The answer here is A, rich in oxygen; it's oxygenated.

This brings us on to task A.

There are two parts to this task.

Do you agree with Sofia? And explain why.

Sofia says, "Blood vessels only take blood away from the heart." What do you think? Do you agree with her? Explain why to a partner or write down some of your ideas.

Did you agree with Sofia? Well, blood vessels transport blood all around the body.

Arteries carry blood from the heart.

Most arteries carry blood which is rich in oxygen to all different parts of the body.

Veins return blood to the heart.

Most veins carry blood with carbon dioxide to be exhaled.

Let's look at the second task.

Jacob's been writing about the human body in adulthood.

Can you find and correct the mistakes and improve his ideas? Read each of those statements and decide which one is correct and which one is wrong.

Do they all need rewriting? Have a go.

Let's check through some answers here.

Yours could be similar.

Now, blood is pumped around the body, not pushed.

Arteries are blood vessels, and most arteries deliver blood rich in oxygen, not carbon dioxide.

Veins are also blood vessels.

Most veins return blood low in oxygen to the heart.

Definitely not the stomach.

And blood vessels are thin tubes which connect our heart to the rest of our body.

They are not wires, because blood needs to be able to flow through them.

Well done for completing that task.

The next part of our lesson is called Representing blood vessels in the human body.

Now, Laura and Aisha want to present the function of blood vessels to other children at school.

Here they are, and Laura says, "I would like to draw a diagram of some blood vessels in the human body, but how will I know which blood vessels are arteries and which ones are veins?" Hmm.

Aisha says, "Well, maybe you could draw different types of blood vessels in some different colours." Yeah, like a nice yellow or a green maybe.

What do you think? Do you have any ideas? Pause the video and discuss.

Restart when you've done that.

Hopefully you've had a good discussion about maybe some different colours that you could use or how you would present this type of data.

Laura says, "Using different colours is a great idea because I can see blue blood vessels called veins on my wrist, so this blood must be blue." Veins on your wrist, oh, yes, of course, I can see that as well.

I wonder if you can.

If you were to hold up your wrist and have a little look at your skin, can you spot any veins through your skin? It may be that you might need to press ever so gently just to try and see where some of those things are.

Here you can see an image of someone's wrist.

Now I can definitely see some little blue lines in there.

Though it's not incredibly clear, is it? Remember, everyone is different, so veins may show up slightly different through different skin.

So Aisha says, "Oh, so the red blood that I see if I cut myself must have come from arteries." Hmm.

What do you think here? If you cut yourself and you see red blood, does that come from arteries? Have you ever seen blue blood before? Does that come from your veins? Does this sound right? Who do you agree with here? Pause the video and discuss.

Restart when you've done that.

Hopefully you've had a good chance to discuss the different types of blood.

Is there red and blue blood? No.

Blood is always red.

The amount of oxygen in the blood will determine how red it is.

So if blood is low in oxygen, or deoxygenated, it is often a much darker red.

Veins are a lot closer to the surface of your body than arteries.

So the darker red blood travelling through veins may appear blue, but only because of how light travels through our skin.

So although it might seem as though they are that different colour, it's actually just a bit of a trick of the light.

Take a moment to have a look and see if you can spot veins or arteries through your skin.

I have a lot in this hand, but not very many in this hand.

Hmm.

Let's pause and think.

Blood will appear blue in blood vessels because.

Which of these statements do you agree with? The correct answer here is C, light travelling through our skin can cause it to appear blue.

Remember, blood is always red.

So scientists will use some scientific diagrams to describe the different systems in the human body.

Here you can see a diagram of blood vessels in the body.

I can also see in this diagram that the lungs have been included as well.

Can you see how the blood vessels attach themselves and go slightly past the lungs? That doesn't mean that blood gets into our lungs, but it allows oxygen to be absorbed and carbon dioxide to be absorbed, so it can be exhaled and the oxygen to be used elsewhere in the body.

Often blood vessels are presented using red for arteries and blue for veins.

However, this doesn't represent the real colour of blood.

It just helps scientists to explain the different journeys of oxygenated and deoxygenated blood.

It's one way that we can teach people how blood vessels work.

Remember, it doesn't mean that blood is a different colour.

So Laura says, "Well, I can use an outline of the human body and draw some lines, like branches on trees, that will represent the blood vessels travelling to and from the heart throughout the body." "Remember to use red for arteries transporting blood rich in oxygen away from the heart, and blue for veins transporting blood low in oxygen back to the heart." So remember, you can represent the different types of blood using the different colours.

Red for oxygenated and blue for deoxygenated.

Let's stop and think.

True or false? Scientists must use real organs for describing different systems in the human body.

The answer here is false.

They don't need to use a real organ, so I wonder if there's something else that they can use.

Let's justify our answer here.

The answer here is: scientists can use scientific diagrams to describe different systems in the human body.

Remember, a diagram is slightly different to a model because it's something that needs to be labelled.

It's not just a picture.

Your diagram is going to show the ins and outs, the ups and downs, and of course, all the names of the different items that are in it.

This brings us on to task B.

Here, you need to complete this scientific diagram to show how blood travels around the human body.

Here you've got the outline of a body and the heart in the centre.

There's also some of those tubes coming off of it.

Now remember, all of those tubes are blood vessels and they go to different areas in the body.

Sam says, "You can use blue and red lines to represent blood travelling through different blood vessels." Izzy says, "I have another idea for how to create a scientific diagram on the next slide." Hmm.

I wonder if she's able to do this in a different way.

You may if you want to do some extra research and see the different spaces that the blood vessels need to go to, or if there are any organs that you might like to include in your diagram.

Here is what Izzy says.

She says, "Well, you could get creative like me, and you could use a straw to blow lines of runny red and blue paint to represent the different blood vessels in the human body or you could use some coloured string instead." So that's really creative, isn't it? You could get tiny little blobs of paint and blow it around the body.

Be careful not to be too splashy though.

Remember, your blood doesn't slosh around in your body like a bottle.

There's also there, you could represent blood vessels using some different colour string, or you could use some wool if you have it.

Best of luck with this task.

Restart the video when you've done that.

How did you get on? Well, your diagrams may look very similar to these.

There is a scientific diagram there showing the heart, the veins in blue and the arteries in red, and on the other side there is what one of the children has created.

They've used some glue and some string to stick down different blood vessels of different colours.

I think they've used some scissors to cut it up so they can make it bend around the body too.

Now, your diagrams may look similar to this or they may be different.

Whatever you've done, hopefully you've been able to show off your understanding of how blood vessels transport blood to different parts of the body and that there are different types of blood vessel that do different jobs.

Let's summarise our learning.

Blood vessels transport blood all around the body, to and from your heart.

Arteries are blood vessels.

Most arteries deliver blood rich in oxygen to all the parts of the body.

Veins are blood vessels.

Most veins return blood low in oxygen to the heart.

Now, blood is always red.

Blood travelling through veins may appear blue because of how light travels through your skin.

And scientists use scientific diagrams to describe different systems in the human body.

Hopefully you've built up enough knowledge from this lesson to know lots more about blood vessels and the different types.

Hopefully you'll go on to use some of this knowledge to maybe help somebody else in the future.

Who knows, maybe some of your models and designs of the future will go on to help other people.

I've been Mr. Wilshire, thank you very much for listening.