Episode 10 – Happy Hearts

How does the heart work?


Hello again alchemy addicts and welcome to my blog post about building my very own human body.

Today Nurse Nanobot and I gave our body a hearty heart and some lovely glubbly blood to carry oxygen and nutrients to all the parts of the body, and to carry waste away.

Press the play button above to listen to us explore the world of your heart and also read loads of interesting facts below!

The Heart

The heart is made of cardiac muscle – a special type of muscle only found here.  Your heart is about the size of your fist and is made up of four spaces – the bottom two spaces are called ventricles and the top two are called atriums.

The dividing wall down the middle of the heart is called the septum.

Your heart squeezes to pump blood out and around your body- you can feel this pumping by feeling your pulse – place three fingers on the side of your neck or on your wrist.  Every pulse beat is a pump.

Did you know that your heart pumps blood around the organs in your body in less than a minute.  That’s speedy stuff!

Carrying Blood Around

Your arteries, veins, and capillaries all carry blood in one direction and one direction only. To stop blood going backwards your heart has strong valves on the entries and exits – valves are like heavy doors that only open one way.

Did you know that a doctor listens for your heart beat with his stethoscope, he is actually listening to the noise of heart valves snapping shut?

And that there aren’t any valves in the arteries which carry blood from the heart, as the bloodflow is so strong it can only go forwards. In the veins going back to the heart the flow is more sluggish, so there are lots of valves in the veins.

Bloody Facts!

Blood, blood, blood – did you know that grown ups have 4 to 6 litres of blood?  That’s the same as three very big bottles of cola.  But unlike pop, blood is like a lovely nutritious soup for your organs – it is made up from lots of ingredients but you won’t find them in the fridge!

The runny bit of your blood is called plasma and it’s actually pale yellow in colour.

Blood looks red because of the red blood cells – these look like squashed footballs and they carry nutrients and oxygen.

Red blood cells contain haemoglobin, a special oxygen-carrying protein, which turns redder when it’s got oxygen attached. That’s why blood carrying oxygen to the organs is bright red, but blood coming back is darker in colour.  Our bodies contain about 25 TRILLION red blood cells in a body – which is quite a lot!

White blood cells are like your own private army, ready to leap into action if bacteria or a virus attack your body, they also clean up dirt and debris along the way.

Blood also contains Platelets – tiny odd fragments of cells that do a good job helping your blood to clot or stick together when you cut yourself to form a scab.

All the blood cells and platelets are made from your bone marrow but the plasma is mainly water which comes from your intestines and the water you’ve swallowed.  It also has some nutrients and proteins of its own but it’s the watery plasma holds everything together.

Blood Types

Did you know that different people have slightly different make-ups of blood?  There are four types of blood – each with their own names – A, B, AB and O.

And each type can be negative or positive – which relates to whether a particular protein called Rhesus is in the blood or not.  In a blood transfusion, you need to make sure the ill person gets the right type.

Do you know what sort of blood type you have?

Nurse Nanobot’s Orrible Old Anatomy Fact


For over two thousand years physicians from the Ancient Egyptians to the Victorians have believed that cutting a patient to let them bleed was a way to cure many illnesses.

All sorts of horrible blades were used – and even leeches – horrible slimy slug-like creatures that suck blood, were used too!



Disgusting Details

When you eat fatty foods, the fat is carried into your bloodstream with all the other nutrients – but beware, if there is too much fat it begins to stick a gunky coating to the walls of the pipes that carry your blood – veins, arteries, and capillaries.

And then its like when the pipes in the sink get clogged up – the water can’t run down as fast.

As all those arteries get narrower, the blood can’t move around as quickly as it needs to and you can risk a heart attack – where your heart doesn’t get enough oxygen to pump properly  – not good news!

That’s why you need to watch how much fat you eat – it doesn’t just make you wobble on the outside, it clogs things up inside!

A healthy diet with lots of fruit and vegetables will help keep your blood healthy and as the heart is a muscle make it a good strong one with stacks of exercise – play lots of sport and games with your friends.  The more you work it the stronger it will be.

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