Nasco Lifeform Heart Model LF00964 can be opened to allow inspection of the chambers and the valves. The texture of the heart, both inside and out, has been duplicated with remarkable realism. By squeezing the heart, students can actually feel that the ventricles are thicker than the atria. To see the valves and ventricular chambers, simply flip the cardiac skeleton forward. Students can also use the replica to identify all of the large vessels entering and leaving the heart. A teaching guide is included.