At this time of year everything gets associated with Halloween and scary creatures. People dress up as monsters of all kinds and use fake blood to make themselves look even scarier.

But, Halloween is just one night so it's good to tell you the full story about what is running through your veins 365 days a year - blood!

To kick off have a look at the video at the top which explains the building blocks of blood. In this video we are going to discover what blood is made of and the roles of the different components.
Blood consists of red blood cells, white blood cells, platelets and plasma.

  • Red blood cells are disc shaped and contain haemoglobin, which is the iron containing protein which transports oxygen in the blood.
  • White blood cells are the warriors, attacking and killing invading pathogens.
  • Phagocytes and lymphocytes are two types of white blood cells. Platelets help to make our blood clot when we fall over and cut yourself.
  • Plasma is a yellow sticky liquid that makes up the majority of our blood. It carries nutrients, hormones and proteins around the body, and is largely made up of water.


White blood cells are really important as we go into the winter as these guys as the warriors inside us, fighting off infections and other diseases.
They make up less than 1% of our blood but they are our first line of defence in keeping us safe from whatever life throws at us.


Just like the white blood cells protect us from attacks inside, sometimes you trip or fall and you can cut yourself. This time platelets in your blood react and cause the a clot to form and this helps to seal the wound. Eventually this will form a scab and at worst you might have a little scar, but without these microscopic platelets it could be a lot worse.

If you want to learn more about blood, or lots of other things you can go to to see more cool explainer videos.

On After School Hub today Phil will be talking more about blood, so tune in at 3pm on RTÉ2 or follow up with thanks to RTÉ Player