Take a look at this complete STEM lesson plan on Blood Cell Basics, designed for grades 3-5. The lesson includes worksheets, connections to engineering, and a hands-on activity where students make a model of a blood cell.
Go to hematology.org to watch a video about anemia . Also at this site, learn all about the symptoms and disorders that can cause anemia.
The Red Cross has a chart showing which blood types can donate to which other types, population of people in different ethnic groups and their blood type and a genetic chart showing parent/child blood types. Very interesting and useful for teachers who might teach blood types and the science of groups.
The Science Museum of Minnesota is an excellent resource for your classroom. Animations of the heart and lungs performing their job. This site also has activities and experiments that you can perform with your class to explain pulse, blood pressure and other topics related to the heart and lungs. And if you are up to it, watch heart and lung surgery.
How the body makes blood – this site has an optional voice over that will read the text aloud to your class. Great for your interactive whiteboard. Additional topics available from this site.
If you have a deep desire to understand blood in more detail including the chemistry and life span of each of the different blood cells, you will want to visit this site. Probably too detailed for your class, but as a science teacher you might enjoy visiting Howstuffworks.com.
Here is a way cool video from Science Kids of the immune system in action. The animation is not narrated, so you will have to study up so you can explain the process as you play the video.
Do the risks of blood transfusions outweigh the benefits? Watch this video and make your own conclusions.