In this session, we cover aspects of the endocrine system. We look at how hormones signal, and discuss the differences between the major feedback mechanisms (negative and positive feedback). In addition, we learn that the endocrine system regulates growth, metabolism, sexual development, and homeostasis to allow our bodies to thrive. Furthermore, we review positive and negative feedback examples, such as water level retention, calcium levels, menstruation, and blood sugar regulation. Positive feedback amplifies the stimulus (ex. labor process where the mom’s brain secretes oxytocin to allow for contractions, then the release of prostaglandins, and more oxytocin is secreted as the cycle continues), while negative feedback decreases the stimulus to maintain homeostasis (ex. if the body’s temperature is high, blood vessels dilate and excess heat is sweated off). We end the session with a review of how hormones signal and great ways to study for the class.