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Abstract
Part I: The "Tell Tale Heart" is an activity during which students familiarize themselves with the structure of the heart. They locate the atria, ventricles, and major blood vessels. Through “surgical” procedures, students perform coronary bypass surgery and correct patent ductus arteriosus. Human and dog hearts are compared in terms of common structure and defects.
Part II: Heartworm Poster has students research the life cycle, epidemiology, and diagnostic procedures and treatment of dog heartworm. Their work culminates with them presenting the information in the form of a poster. After they have completed their work they are given supplemental information and are asked questions about heartworm disease.
Part III: In Heartworm Microfilariae students examine a stained smear of dog blood containing microfilariae and count living microfilariae in a fresh blood sample.

Appropriate Levels
High School Biology: Regents, General, and Honors.

Time Required
Part I: “The Tell Tale Heart” - approximately 60 minutes for the procedures.
Part II: “Dog Heartworm Poster” - one period to start work and then a week outside of class as homework should be adequate. After the poster is complete, the additional information and questions can be given as a homework assignment.
Part III: “Heartworm Microfilariae ” - two periods: one for making and staining blood smears containing microfilariae, and one lab for examining and counting living microfilariae.