This course provides students with an understanding of an introduction to the mechanisms of how the body works, concentrating on osmoregulation and excretion, digestion, nerves and muscles, how animals adapt physiologically to environmental challenges and addresses the basic physical and chemical principles that underlie physiological processes. Several biological systems are considered, including respiratory, circulatory, digestive and metabolic, thermoregulatory, osmoregulatory, renal, nervous, musculoskeletal, neural, hormonal, and sensory. This course will provide an overview of animal physiology (how animals work) with a comparative approach whenever possible. The concepts of homeostasis and feedback-mediated regulation will be central themes of the course, and we will also discuss the functional organization of organ systems with particular attention to the ways in which they may interact to maintain a relatively stable internal environment in the face of fluctuating external conditions. We will also pay special attention to the cellular and subcellular mechanisms that provide the foundation for physiological processes at the multicellular organism level.