Here's why:
* Produced by living cells: Hormones are synthesized and released by specialized cells in endocrine glands or other tissues.
* Circulates in blood: Hormones travel through the bloodstream to reach their target cells.
* Specific stimulatory effects: Hormones bind to specific receptors on target cells, triggering a cascade of events that lead to a specific response. This response can be stimulatory (e.g., growth, increased metabolism) or inhibitory (e.g., decreased blood sugar levels).
Examples of hormones include:
* Insulin: produced by the pancreas, regulates blood sugar levels.
* Growth hormone: produced by the pituitary gland, promotes growth and development.
* Testosterone: produced by the testes, responsible for male sexual characteristics.
* Estrogen: produced by the ovaries, responsible for female sexual characteristics.
Let me know if you'd like to explore specific hormones or their functions in more detail!
