Learning aims:

Students are supposed to learn that red blood cells are the transporters of respiratory gases, oxygen and carbon dioxide. They contain haemoglobin that makes temporary bonds with the molecules of the gases. Apart from that, blood carries substances in the body that are vital to cells or which, on the contrary, are excreted by cells. Some of the substances play an important role, for example hormones that regulate different processes in the body.


A textbook

Suggestions for use:

Ask pupils to describe their idea of what happens to oxygen on its way from lungs to brain tissue. They can possibly work in pairs or groups. They present their description of oxygen journey and then work on making their ideas more accurate. Different sources of information can be used.

Students can propose a procedure to prove carbon dioxide in exhaled air.

Talk about other substances blood carries.

Ask students to design and make a toy (a puzzle) for younger pupils – to match a source of production of substances carried by blood in the body and target organs where the substances are needed.

Possible questions:

  • If there is not enough oxygen in the brain, a brain death occurs. How does oxygen get from lungs to brain?
  • What other substances blood carries? Whence and whither?