What human body system affects almost every organ and cell in the body? The endocrine system. The endocrine system contains 9 major glands and organs that produce, store, and secrete hormones. Secreted hormones control everything from body temperature, heart rate, and blood pressure to reproduction, the sleep-wake cycle, and our reaction to stress. Hormones enter the blood system and are delivered to all parts of the body where cells with specific receptors take up the hormones they need and regulate cell function.

Each of the major glands of the endocrine system produce one or more hormones that can be characterized as peptide, lipid-derived, or amino acid-derived chemicals. Many people are familiar with the term steroid. They may have heard the term in reference to athletes using steroids for muscle development, performance enhancement, or for treatment of a severe joint inflammation after an injury. Structurally, steroids fall into the lipid hormone category. They are not water soluble and include chemicals that are primarily ketones or alcohols in structure.