Class begins with discussion of students' answers to the two questions given as assignment in the previous lecture. Professor Saltzman talks about the basic concept of biomedical engineering and two separate aspects of it: gaining better understanding of human physiology and developing ways to improve human health. He then introduces the term homeostasis, and talks about parameters that are involved in controlling this state. Finally, the structure of the phospholipid is discussed and how it constitutes the cell membrane.