What substances are typically secreted by exocrine glands?

Exocrine glands specifically secrete their products, which include a variety of chemical substances, directly into ducts that lead to the surface of an organ or into cavities within the body. This is a defining characteristic that differentiates them from endocrine glands, which release hormones directly into the bloodstream. Exocrine secretions can include enzymes, mucus, sweat, saliva, and digestive substances, all of which play crucial roles depending on where they are released.

For instance, salivary glands release saliva into the mouth, and sweat glands release sweat to the skin's surface, providing examples of how these glands function in practice. This ducted mechanism allows for the regulation and directed delivery of these substances to specific sites of action within the body or outside of it.

In contrast, hormones (the first option) are generally associated with endocrine glands and circulate throughout the body in the bloodstream rather than through ducts. Electrolytes and antibodies also do not fit the definition associated with exocrine gland secretion, as they are not primarily secreted through ducts in the same manner. Electrolytes are typically found in bodily fluids and are regulated through various mechanisms rather than being duct-secreted. Antibodies are produced by immune cells and typically enter circulation rather than being secreted