What type of glands secrete their substances into tubes or ducts?

Exocrine glands are specialized structures that secrete their substances through ducts or tubes to specific locations in the body. These glands are crucial for various bodily functions, including digestion and temperature regulation. For instance, sweat glands release sweat onto the surface of the skin through ducts, and salivary glands transport saliva into the mouth through their respective ducts.

In contrast, endocrine glands release hormones directly into the bloodstream, allowing for broader distribution throughout the body without using ducts. Hormonal glands refer to endocrine glands, and lymphatic glands primarily relate to the immune system and do not have the duct systems typical of exocrine glands. Thus, the defining characteristic of exocrine glands is their ductal secretion, making them distinct from other types of glands.