Now you have a basic function for the blood with the model of a delivery system and you have a basic structure for the blood. Let's see if we can put it all together to have a more detailed model of what the blood looks like and does.

Blood has several functions. These are listed below. Talk with your group and see if you and describe fully how and why the blood might have these functions.

1. Defender in the body

2. Transporter of:

• electrolytes
• oxygen
• vitamins
• nutrients
• hormones
• carbon dioxide

If someone in your class investigated blood cells during the Cell Project, you might have seen that blood cells are different from other cells in the body. Can you name some of these differences?

The disc like shape of red blood cells allow them to squeeze through the tiny capillaries. And rapidly diffuse oxygen into the cells. Look at the picture below and see if you can guess how this might happen.

Look at the pictures and/or animation your teacher will show you about the blood.

How does this model differ from yours?

Are there any surprises?