The answer is a Gland. It is a cell or organ that secretes substances for use elsewhere in the body, or for elimination as waste. Secretion being a product of gland if it's useful to the body and an excretion being a product of the gland if it's a waste product. Glands may be exocrine or endocrine; endocrine glands lose contact with surface; have no ducts; secretes products directly into the blood due to having a high density of blood capillaries while exocrine glands secretes to the body surface or lumen; and maintain contact with surface via a duct.
Absorption is a process that takes place in the small intestines or ileum of the GI tract, in which simple and soluble nutrients are absorbed into the blood stream.
Absorption is enhanced by several adaptations of the gut such as large surface area of the gut which directly facilitates absorption of nutrients.
Presence of villi and microvilli in the gut increases the surface area for absorption of nutrients in the ileum.
