Endocrine vs exocrine glads.
A gland is an organ that produces and releases substances such as hormones, enzymes, or fluids. There are two main types of glands: Endocrine glands – Release hormones directly into the bloodstream (e.g., thyroid, pituitary, adrenal glands). Exocrine glands – Release substances through ducts to the surface of organs or the skin (e.g., sweat glands, salivary glands, digestive glands).