Why It Matters: The Endocrine System

Why describe the components and role of the endocrine system?

The endocrine system includes the glands of the body and the hormones that they produce. The nervous system controls the glands directly by stimulation. The glands of the endocrine system can also be controlled as by chemical receptors in the blood. The endocrine system controls body processes through the production, secretion, and regulation of hormones, which serve as chemical “messengers” functioning in cellular and organ activity and, ultimately, maintaining the body’s homeostasis. The endocrine system plays a role in growth, metabolism, and sexual development. In humans, common endocrine system diseases include thyroid disease and diabetes mellitus. In organisms that undergo metamorphosis, the process is controlled by the endocrine system. The transformation from tadpole to frog, for example, is complex and nuanced to adapt to specific environments and ecological circumstances.

 Photo A shows a tadpole. Photo b shows a frog that has developed legs but still has the tail of a tadpole. Photo C shows a fully grown frog.

Figure 1. The process of amphibian metamorphosis, as seen in the tadpole-to-frog stages shown here, is driven by hormones. (credit “tadpole”: modification of work by Brian Gratwicke)

Learning Outcomes

  • Identify different types of hormones and explain the regulation of hormone production
  • Describe the two types of hormone receptors
  • Describe how hormones regulate body processes
  • Describe the role of different glands in the endocrine system