IIn this module, we return our attention to the endocrine system and its role in the maintenance of homeostasis. In particular we consider the hypothalamus-pituitary axis, which integrates signals from the nervous system and from the blood to regulate most homeostatic functions, including growth, ion balance, fluid balance, response to stress, and energy use. The first lesson gives an overview of the hypothalamus-pituitary axis and its actions in regulating growth of the body. In later lessons we consider how this complex negative feedback loop governs the body’s energy use and its response to stress. Then, later in lesson 3, we turn our attention to the simple reflex loop by which the endocrine pancreas regulates metabolism in both the fed and fasted states and the failures of this system (diabetes mellitus). The hypothalamus-pituitary axis and its control of reproduction in both males and females are considered in the next module (Module 9). The things to do this week are to watch the 6 videos, to answer the in-video questions, to read the notes, and to do the two problem sets (endocrine system and fuel homeostasis). Please note that each module can stand alone, however, it will be most effective if you do the first two videos (H-P-axis) before any of the others. The notes provide a more detailed summary of each topic and again we encourage you to use the resource (videos and/or notes) that works best for you. Please do try the problems sets for self-review. Both your understanding and retention will increase with application of the new learned information.