Lesson video

This lesson is the human brain and is from the unit: Coordination and control: the human nervous system.

Hi there.

My name's Mrs. McCready and I'm here to guide you through today's lesson, so thank you very much for joining me today.

In our lesson today, we're going to describe the main regions of the brain and their functions.

Now, we'll come across a good number of key words today, and they're displayed up on the screen for you now.

You may wish to pause the video and make a note of them, but I will introduce them to you as we come across them.

So in our lesson today, we're going to first of all look at the role of the brain before we look at the areas of the brain.

So you ready to go? I am.

Let's get started.

So we know that the brain is part of the central nervous system, and it has an incredibly important role as part of that.

It is made of billions of neurons, an extremely complicated organ.

And these neurons are all working together, receiving information from the peripheral nervous system and coordinating our response to that information.

So the neurons are working together with other aspects of the peripheral and the central nervous system in order to enable us to respond effectively to our internal and our external environments.

So that's things that are happening within our body and things that are happening outside of our body.

Now, the brain receives information from across the whole body.

And across the whole body there are sensory organs which are detecting changes to the environment from within our body and out with our body.

And that information about those changes in the environment are being relayed up to the brain so that it can coordinate an effective response.

Now, those responses are then sent back down, are the neurons, to the various different parts of the peripheral nervous system and lead to a response.

Now, that response might be something like movement of a muscle, or it might be something like adjusting the amount of water that is being collected by the bladder.

So some of those are responses that impact on our external environment, and some are responses that impact on our internal environment.

But all of them are coordinated by the brain and relayed back to the various different parts of the body which needs to have a response via neurons and via the electrical impulses that those neurons are able to carry.

Now, some of those responses happen without conscious control.

They're ticking along in the background without us realising that they're happening.

So all the things that are happening inside your body that you aren't physically, mentally controlling consciously, these are all the things that are being controlled without conscious control.

These are happening unconsciously.

So these are things that are just sort of running along in the background, such as our body temperature, our heart, and our breathing rate, and how they change in response to the activities that we're doing.

Things like how we vomit and sneeze are also controlled unconsciously.

We don't have any control over the actual act of vomiting or the actual act of sneezing.

We may know that it's coming, but that's about as much as we can do about it.

So these are all examples of aspects of our body that are happening without us consciously controlling them.

So these are processes that the brain is operating and controlling, but we don't need to be thinking about.

Many of the processes that the brain controls, however, are controlled with conscious thought.

So these are aspects of our response, which we are thinking about, we are making decisions about, we are choosing to act on.

So these include things like how we communicate with each other, how we learn and remember, and how we perceive the environment around us and choose to respond to it.

So these are our conscious choices, but these can only happen when we're awake and when we're aware of the surroundings around us.

When we're asleep or when we're unconscious for other reasons, then these conscious thoughts cannot occur.

So we have these two aspects of our behaviour, unconscious behaviour and conscious behaviour, both of which are being controlled by the brain.

Now the brain is made up of two hemispheres, hemi meaning half, spheres meaning a sphere, you know, like a 3D circle.

So there's the left hemisphere and the right hemisphere, and the neurons are entering the brain at the bottom of the brain and then splitting up into the left and the right hemispheres.

So the neurons on the left side of the body are entering and splitting across at the bottom of the brain and going to the right hand side of the brain.

And the neurons on the right hand side of the body are coming in at the bottom of the brain, crossing over and going to the left side of the brain.

So the left side of the body is controlled by the right side of the brain, and the right side of the body is controlled by the left side of the brain.

However, this doesn't mean that the left side of the brain is only responsible for certain activities like creativity, and the right side of the brain is only responsible for other activities such as numeracy.

That's absolute nonsense.

The brain distributes its functions across the whole area of it.

And while certain areas of the brain have been identified as being responsible for controlling certain things like memory or how we hear words, how we interpret language, and how we make language, how we speak, it doesn't mean to say that only the left or the right part of the brain is responsible for that.

That's actually spread fairly equally across all of the brain.

So let's just stop and check our understanding.

So Sophia, Sam, and Jun have given descriptions of the role of the brain, but who is correct? So Sophia says the brain is part of the central nervous system and is made up of billions of neurons.

Sam says, the brain controls our body and only our response to the external environment.

And Jun says the brain controls consciousness including our heart rate, emotions, and memories.

So who is correct? I'll give you five seconds to think about it.

Okay, have you decided? Well, hopefully you've chosen Sophia as describing the role of the brain correctly.

Well done if you got that right.

So what I'd like you to do now is to summarise the role of the brain.

I suggest you make a mind map, but if you prefer an alternative layout, then that's absolutely fine as well.

But what I would like you to do is to include the position of the brain within the nervous system, what the brain is made up of, it's roll within the body, the ideas of conscious and unconscious processes, and the overall structure of the brain.

Then once you've created your mind map or other sort of visually interesting notes, I'd like you to consider this.

The human brain has increased in size as early human predecessors evolved, and you can see that in the picture there where Australopithecus has a very small brain compared to homo sapiens, that's us, a much, much larger brain, and the brain size increases as we go from left to right as we come to more modern human.

What I'd like you to do is to suggest why this is important for survival.

Why was it that an increasing brain size enabled Homo erectus and the Neanderthal man to survive well enough to be able to evolve into Homo sapiens, us? So pause the video and come back to me when you're ready.

Okay, let's look at what you've done then.

So firstly, I asked you to make a mind map of the role of the brain.

So in the centre I've put the word, the brain, and around it.

I'm gonna include lots of information, including that the brain is in the central nervous system.

It is made of billions of neurons.

It has two hemispheres, the left and the right, and the right controls, the left side of the body and vice versa.

I've also said that the brain controls responses to internal and external environments.

That conscious processes include thoughts, chosen decisions, learning and memory, and these occur when we are awake.

There are also unconscious processes, including heart and breathing rate, body temperature, sneezing and vomiting, and these occur all of the time.

So just check over your work.

Have you included all those really important points? Add to anything that you have and make sure that all of the facts are correct.

Well done.

Then I asked you to suggest why an increase in brain size in human predecessors was important for survival.

So you might have written that an increase in brain size led to an increase in brain function and being able to process the input from the environment and generate a response more quickly and more intelligently will have helped increase survival.

So just check over your work, make sure you've got the flavour of that written in your notes, make any amendments or additions if you need to, and well done again.

Okay, let's move on to the areas of the brain.

So the brain is made up of three main areas, the cerebral cortex, the cerebellum, and the brainstem or the medulla, or the medulla oblongata.

Now these three areas have specific responsibilities.

So the cerebral cortex, which is the largest part of the brain, and that's the top part of the brain sitting in the top part of the skull.

So the cerebral cortex is responsible for consciousness and all the things that happen whilst we are conscious and able to think about what we are doing, such as our intelligence, our memory, our use of language, our thoughts and our feelings, and the perception of thoughts and feelings of other people as well, and the ability to process senses and the information that we perceive about our external environments such as our vision, our sound, our smell, and taste and touch.

So this is the cerebral cortex.

This is the largest part of the brain involved in conscious, thoughtful activity.

The cerebellum sits at the back of the skull and is responsible for conscious movement.

It's a reasonably large section of the brain, but substantially smaller than the cerebral cortex, and it is responsible for conscious movement, including balance and coordination.

So how well you balance and coordinate yourself is down to the work of the cerebellum.

And the last part of the brain that we are looking at is called the brain stem.

You may also see it be called the medulla or the medulla oblongata.

Now the brainstem is in evolutionary terms, the oldest part of the brain.

Now the brainstem is right at the very bottom of the brain.

It's quite a small section of the brain, but it's a highly important part because it regulates many of the unconscious activities that are happening within our body.

So these autonomic processes, these unconscious processes include things like our heart rate and our breathing rate, our body temperature, and our reflexes, including our vomiting and our sneezing reflexes.

So these are all unconscious or autonomic processes that are being controlled by the brainstem.

So let's just check our understanding.

Which of these three labels points to the cerebellum.

I'll give you five seconds to think about it.

Okay, so the cerebellum is identified by letter C.

Well done.

So which part of the brain is responsible for conscious movement? Is it the cerebral cortex, the cerebellum, or the brainstem? Okay, you should have chosen the cerebellum.

Well done.

And which part of the brain is responsible for controlling heart rate? Is it the cerebral cortex, the cerebellum, or the brainstem? Okay.

So you should have chosen the brainstem for that answer.

Well done.

And finally, which part of the brain is responsible for memory, the cerebral cortex, the cerebellum, or the brainstem? And you should have chosen the cerebral cortex.

Excellent job.

So what I'd like you to do now is to firstly label the diagram of the brain indicating those three main areas and their functions.

Then I would like you to explain why someone who has experienced a brainstem injury is able to talk about past events, but may struggle to control their body temperature.

Then finally, I would like you to consider this, that people with dementia remember things that happened a long time ago, but forget things that have recently happened.

So which area of the brain is affected by dementia and what process is impaired? So pause the video and come back to me when you're ready.

Okay, let's review our work.

So firstly, I asked you to add labels to the diagram and indicate the three main areas and their functions.

So first of all, you should have identified that the cerebral cortex is this large part of the top of the brain, and this is responsible for consciousness, intelligence, memory, language, thoughts and feelings and senses processing.

You should have also identified the cerebellum, this relatively large section at the back of the brain.

And this is responsible for conscious movement, balance and coordination.

And then also finally, the brain stem, also known as the medulla, and this is responsible for unconscious processes, including heart rate, breathing rate, body temperature, reflexes, sneezing, vomiting.

So just review over your work, make sure you've got all those salient points and well done.

Then I asked you to explain why someone who has experienced a brain stem injury is able to talk about past events, but may struggle to control their body temperature.

So you should have written that people with a brainstem injury have damaged part of the brain that controls unconscious processes such as body temperature, heart rate, and breathing rate.

But the cerebral cortex undamaged, so this means that they may struggle to control unconscious processes, but they should be able to function normally with consciously controlled parts of the brain.

So again, just review your answer, make sure you've got those salient points.

Good job.

Well done.

And then finally, I asked you to suggest which area of the brain is affected by dementia and which process is impaired when people who have dementia struggle to remember things that have recently happened.

So you should have written that in dementia, it's the cerebral cortex which is affected and this impairs the ability to form new memories.

So this is why old memories can be recalled, but new memories are not created.

So again, just check over your work and see if you've got all those salient parts.

And well done, that was really quite tricky to explain.

Okay, in our lesson today, we have seen that the human brain is an organ.

It is made up of billions of neurons and is found within the central nervous system.

It is responsible for processing information from the nervous system and producing responses to it.

It comprises of three main areas, the cerebral cortex, the cerebellum, and the brainstem.

The cerebral cortex coordinates consciousness, the cerebellum coordinates conscious movement, and the brainstem or medulla coordinates unconscious responses.

So thank you very much for joining me today.

I hope you've enjoyed that and learned plenty, and I hope to see you again soon.

Bye.