Students learn all about the body's essential mighty organ, the heart, as well as the powerful blood vascular system. This includes information on the many different sizes and pervasiveness of capillaries, veins and arteries, and how they affect blood flow through the system. Then students focus on heart valves, how they work and what might cause them to fail, coming to realize the value of prosthetic heart valves, a life-saving biomedical invention. Students are asked to evaluate the different options for heart valve replacements based on performance criteria, and provide a summary of their advantages and disadvantages. This engineering curriculum meets Next Generation Science Standards (NGSS).