Summary
This section provides an in-depth look at the endocrine system, explaining how hormones are produced, transported, and act on target cells. It distinguishes between the mechanisms of protein and steroid hormones, emphasizes the importance of feedback loops in maintaining homeostasis (such as in thyroid and adrenal function), and highlights emerging concerns such as endocrine disruptors. Understanding these processes is critical for grasping how organisms regulate metabolism, growth, reproduction, and response to stress.