Heart valves play a vital role in efficient circulation of the blood, and the details of their physical structure are related crucially to their function. However, it can be challenging for the learner to make the mental connection between anatomical structures of valves and the changing pressure gradients that the valves experience and come to an understanding of valve function. Making your own simple, inexpensive working models allows your students to visualize valve action quickly and easily, and to predict effects on function if valve structure were altered. A link to a video showing use and construction of the working valve models is given.

This simple role-play exercise involves the whole class in learning about the function of hormones in promoting homeostasis and the value of negative feedback, using the example of regulation of calcium ions by parathyroid hormone.