 There are two main kinds of glands that are found in your whole body and glands are made of epithelial tissue because their primary purpose is secretion of something. The two main kinds of glands depend on where the substance is being secreted. So if the secretion is being produced and secreted outside of the body like sweat glands, then those glands are exocrine glands. If the secretion is being secreted inside the body into the blood to be transported somewhere else, then those are endocrine glands. Exocrine glands usually have ducts associated with them, and so they produce their secretion when they let it drip out or whatever, squeeze out through a duct, which is like a neck-long, squirty thing. Endocrine glands are only associated with blood, so they actually are highly vascular because you have to be close to the blood in order to dump your stuff into it. So the stuff that gets dumped is hormone, and the hormone travels through the blood to a distant target. That's actually what defines the endocrine system. We'll talk about the endocrine system in detail when we go over the nervous system because it's also kind of a controlling system, but exocrine glands, we're going to look at salivary glands in the next section, and those are definitely exocrine. Okay, review next.