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Episode 13 – Germs & Immunity

How does the immune system work?

hallux-leaningHello again anatomy fans and welcome to my blog post about building my very own human body.

Today Nurse Nanobot and I worked on our body’s immune system.

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

Immunity is what fights off germs and keeps you safe.  If my body doesn’t have immunity, if he were to catch a cold, it could mean curtains!   And it all starts with germs.

You might think that germs are just blobs of dirt, but they are living things – organisms just like you or a cat or a pot plant. However, they’re very small – some are so small they can’t be seen with a normal microscope.


Bacteria are tiny living creatures that take nutrients from around them to live. They can live pretty much anywhere as long as there is something to eat!

Some bacteria are good and actually help with some of our body’s processes, such as in our intestines.  But others make us poorly.  If you’ve had tonsillitis, with white blobs on your throat, or an ear ache or tooth decay, then that’s evidence of bacteria at work.


Viruses are another type of germ, and contagious diseases like chickenpox are caused by viruses.

They can’t survive outside living things for long, but can be passed between people through sneezes or dirty hands s and then set up home inside our body and make us feel very poorly.

And you thought viruses were just something your computer could get!


Another type of germ is funghi.  Fungal infections often affect the skin or soft tissues like your mouth and cause soreness or itching.

But don’t worry, they’re normally not serious.


The last type of germ we’re looking at is protozoa – tiny organisms that spread disease through water. If you’ve ever had to run for the toilet with a tummy upset, that could have been a protozoa at work!

halluxIn-built Protection!

White blood cells are the body’s policemen – they’re called leukocytes.

There are two main sorts: phagocytes which eat up germs and lymphocytes which hold details about the germs to help your body recognise them again.

Lymphocytes are a bit like the detectives in the police force – keeping careful notes, tracking baddies down and pouncing on them before they’ve got away!

White blood cells are found all over the body – but mainly in the bone marrow, spleen and lymphatic system. That’s a special high speed network in the body just for these germ-fighting cells.

If you have ever had swollen glands, you might have felt your own lymphatic system without realising it.

These glands are actually lymph nodes which are home to many million white blood cells.  You’ve probably felt the ones on your neck when you’ve been ill, but there are nodes in your armpits and in your groin – around the bottom of your underpants!

Nurse Nanobot’s Orrible Old Anatomy Fact


You have probably had vaccinations or ‘jabs’ at the doctors or at school.  These there are injections that help your body fight serious illnesses.

Vaccinations are all thanks to farm milking maids in the 1800 – and a doctor called Edward Jennings.

The milkmaids had cow pox, a nasty disease where you get nasty blisters all over. However, it’s not as bad as smallpox which is a dreadful disease that covers you from head to foot in blisters and has killed thousands of people throughout history.

But here’s the clever bit: Edward Jennings noticed that milk maids who caught cow pox never got small pox.

So he collected samples from milkmaid’s blisters to develop the world’s first smallpox vaccine – and as a result smallpox has been virtually wiped off the face of the planet.

So next time you see a milk maid say thank you!

All vaccines work in this way – a tiny weakened bit of the disease, or a similar disease, is injected into your body so that the clever white blood cells can learn to recognise and fight it. So if you ever catch the real thing your body already knows its tricks and can see it off!


Disgusting Details

Germs can travel from person to person through our breath, coughs, sneezes and from touch – that’s why it’s important to use disposable tissues and to cover your mouth and nose when you cough and sneeze, and to remember to wash your hands frequently with soap and water, especially after using the toilet.

You may be clean and healthy but other people who have used the toilet might not be – and poo contains some particularly nasty germs that can be spread on taps and door-handles.

Two nasty bugs worth washing your hands for are E-coli and campylobacter – both can cause dreadful diarrhoea and vomiting, and can even kill, so its worth spending a minute scrubbing those paws. It’s better than a week on the toilet!

That’s it for today.  Join me and Nurse Nanobot on our next blog, where we will tell you what happened when we knitted in some nerves.

See you next time for more medical mayhem!

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Professor Hallux Builds a Body

Find out out how to build a human body with Professor Hallux and Fun Kids

More From Professor Hallux Builds a Body