What is the main function of exocrine glands?

The main function of exocrine glands is to secrete substances through a duct. Exocrine glands differ from endocrine glands, which release hormones directly into the bloodstream. Instead, exocrine glands produce and release various substances, such as enzymes, mucus, and sweat, through ducts that lead to specific sites in the body, including the surface of an organ or into a body cavity. This secretion process is essential for various physiological functions, such as digestion, temperature regulation, and lubrication.

In contrast, the other options represent functions that either pertain to different types of glands or cellular processes not directly related to exocrine gland function. For example, the transport of nutrients across cell membranes describes a function related to cellular transport mechanisms rather than secretion through a duct. Similarly, storing waste products does not align with the secretion purpose characteristic of exocrine glands. Therefore, the correct understanding of exocrine gland function highlights their role in the targeted release of substances through ducts.