Endocrine Glands: These glands release hormones directly into the bloodstream to regulate bodily functions such as metabolism or growth.
Exocrine Glands: These glands secrete substances through ducts onto surfaces or cavities (e.g., sweat glands).
Pituitary Gland: Often referred to as the "master gland," it controls numerous other endocrine glands by releasing hormones that regulate their function.