After an introductory segment contrasting the human endocrine and nervous systems, this program addresses the complex physiology of the endocrine system. Topics include the endocrine organs and glands; the characteristics of hormones and the process of signal transduction; hormonal regulation of blood glucose and blood calcium levels; the roles of growth hormone, thyroid hormone, testosterone, and estrogen in bodily development; hormones and reproduction; and hormonal involvement in the fight-or-flight response. A viewable/printable instructor’s guide is available online. A Films for the Humanities & Sciences Production. A part of the series The Human Body: How It Works. (21 minutes)