How do endocrine glands secrete hormones?

Endocrine glands are specialized glands that release hormones directly into the bloodstream, which is the primary method of hormone secretion in the endocrine system. This direct secretion allows hormones to travel throughout the body and reach target organs or tissues that have specific receptors for those hormones. By entering the bloodstream, hormones can exert their effects on various physiological processes such as metabolism, growth, reproduction, and mood regulation.

In contrast, other options describe mechanisms that are not characteristic of endocrine hormone secretion. For instance, the secretion through ducts to the digestive system refers to exocrine glands, which release their secretions via ducts directly to specific sites, such as gastrointestinal juices. Excretory pathways typically involve the elimination of waste products from the body rather than the delivery of hormones. Lastly, nerve endings transmit signals primarily for rapid communication between nerve cells and not for hormone release in the manner typical of endocrine glands.