Identify and describe the main classes of hormones and their functions.

Hormones are chemical messengers that are produced by the endocrine glands and are essential for regulating various bodily functions. There are several main classes of hormones, each with their own specific functions:

1. Peptide hormones: These hormones are made up of amino acids and include insulin, glucagon, and growth hormone. They regulate metabolism, growth, and energy balance.

2. Steroid hormones: These hormones are derived from cholesterol and include cortisol, estrogen, and testosterone. They regulate metabolism, immune function, and reproductive processes.

3. Amino acid-derived hormones: These hormones are derived from amino acids and include thyroid hormones and epinephrine. They regulate metabolism, heart rate, and stress response.

4. Eicosanoids: These hormones are derived from fatty acids and include prostaglandins and leukotrienes. They regulate inflammation, blood clotting, and smooth muscle contraction.

Each class of hormones plays a crucial role in maintaining homeostasis and coordinating the body's response to various stimuli. They act on target cells and tissues to regulate processes such as growth, metabolism, reproduction, and stress response. Overall, hormones are essential for maintaining the body's internal balance and ensuring proper functioning of all bodily systems.