Aspiring anatomists label a photograph of a human heart by comparing it to a colored diagram on the same page. The video that is mentioned in the procedure does not seem to be available, but the overview provides plentiful background information, a detailed set of instructions, and a crisp worksheet focused on the external view of the heart. Classroom slides that you can project for a larger view of the image are available at the publisher's website. Use the lesson alone or in conjunction with the next lesson in the larger unit, which takes a look at the interior of the heart.