Many adults living in the US become curious about doctor prescribed growth hormone replacement therapy when they begin to experience chronic symptoms, such as low energy, fatigue and low sex drive, that are frequently associated with your bodyâs declining growth hormone levels.
External, or exocrine, secretion is distinguished from internal, or endocrine, secretion. In external secretion the products elaborated by a gland are released into the external environment; the secretion first enters the glandular duct, from which it is discharged onto the surface of the body or into hollow organs.
Endocrine Glands. Endocrine glands lack ducts-they are often referred to as ductless glands.. Endocrine glands secrete directly into the tissue fluid that surrounds them.The product of endocrine glands are hormones, which they release into the extracellular space.lassification of Glands. Glands are classified as endocrine (internal seceretion) or exocrine (external secretion) depending on where they release their product and unicellular or multicellular based on the number of cells in the gland.