Final answer:
Glands that release their products directly into the blood, like the adrenal gland, are called endocrine glands, as opposed to exocrine glands that use ducts.The correct option is 1).
Step-by-step explanation:
Glands that secrete their products directly into the blood, such as the adrenal gland, are classified as endocrine glands. In contrast to exocrine glands which release their contents through a duct that leads to the epithelial surface, endocrine glands release hormones directly into the interstitial fluid and blood stream without the use of ducts. The pancreas is a unique example as it functions as both an endocrine gland and an exocrine gland, releasing hormones into the blood and producing digestive juices into the small intestine via ducts.
Endocrine glands are glands that secrete their products directly into the blood rather than through ducts. These glands release hormones that travel through the bloodstream to target organs and regulate various body functions. Examples of endocrine glands include the adrenal gland, thyroid gland, and pituitary gland.