How our body protects us: Lymphocytes, blood cells and more!

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Your body normally does a great job at protecting you from infections!

When you catch an infection, your body does everything it can to try and fight back. One of the things it might try and do is cool you down… by making you hot!

Welcome to the immune system in action!

Microbes like being at the body’s normal temperature – that’s 37 degrees Celsius. They don’t like it when the body raises the temperature to help fight off infections. That’s what happens when you have a fever.

Skin is designed to be a tough waterproof barrier that keeps foreign things out. That’s why if you have a cut or a graze, it’s a good idea to wash and cover it up so that infections can’t sneak in.

Even where there are holes like your ears and nose, you’ll find substances like mucus, earwax and hairs – all designed to trap particles and viruses.

If you’ve got a chest infection, you might have lots of STREPTOCOCCUS PNEUMONIAE bacteria. There’s certainly a lot of them around and they typically gather in pairs.

Click here to find out more about your body!

As you may know, there’s more to blood than just, well, blood. As well as red blood cells that carry oxygen to all parts of the body, platelets and other substances suspended in a fluid called plasma, blood also contains white blood cells that help the body fight infections.

Look, here comes a LYMPHOCYTE – that’s a type of white blood cell – coming to the rescue!

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Some Lymphocytes produce special proteins called antibodies which attach to the surface of the harmful microbe – like a key in a lock – helping to destroy them.

Different lymphocytes have different keys so sometimes it takes a while for the human body to find the right match.

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But when it’s found, the microbes are in trouble. Sometimes antibodies will cause the harmful microbes to burst open to prevent them from reproducing.

Lymphocyte then use its antibodies to alert the PHAGOCYTES. They’re a different type of white blood cell, chasing the bacteria and eating it.

The clever thing about the immune system is that once white blood cells have successfully defeated a bacteria, other cells – called memory cells – remain in the body. This way, if the same microbe appears again, the body has its defences ready.

Activities for you to do

Activity 1: Create a microbe garden: how many different types of microbe can you find on different foods? Find out how microbes like to grow best. Click to find out more Microbe Garden

Activity 2: Microbes are so small scientists can only see them through a microscope! Have a go at fashioning your own microscope out of everyday items. You might not be able to see microbes, but you will see loads of cool things you cannot usually see with your eyes alone. Click to find out more MakeYourOwnMicroscope

And for teachers
Run a lesson with your students on the immune system: Primary / Secondary

  1. The human body has special defences against microbes and infections.
  2. It comes with its own barrier systems such as skin and hair to defend against microbes.
  3. And inside the human body, the immune system helps defend against microbes.
  4. The immune system is comprised of different cells and proteins to defend against microbes.

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