What is the primary function of glands in the endocrine system?

The primary function of glands in the endocrine system is to create and secrete chemical substances, specifically hormones. Hormones are essential for regulating various physiological processes in the body, including metabolism, growth and development, tissue function, and mood. The glands release these hormones directly into the bloodstream, allowing them to travel to different organs and tissues, where they exert their effects.

In contrast to the other functions mentioned, glands in the endocrine system do not primarily produce digestive enzymes or filter toxins; those roles are mainly associated with different systems, such as the digestive system and the liver. Maintaining body temperature is primarily the responsibility of the hypothalamus and the integumentary system, rather than the endocrine glands themselves. The key characteristic that distinguishes the endocrine system is its reliance on the secretion of hormones to communicate and regulate bodily functions rather than direct actions like filtration or digestion.