The term of the endocrine system refers to a collection of glands that produce hormones which are released into the bloodstream and regulate various bodily functions. The most common example of a GLANDULAR endocrine organ is the thyroid, which produces hormones that regulate metabolism. Other glands in the endocrine system include the pituitary, adrenal, and pancreas, which produce hormones that regulate growth, stress, and blood sugar levels, respectively.