What are the secretions that the endocrine glands release directly into the bloodstream that influence the welfare of the entire body?

The endocrine glands produce and secrete hormones, which are chemical messengers that travel directly into the bloodstream. These hormones have a wide-ranging influence on various physiological functions across different systems in the body, helping to regulate processes such as metabolism, growth, reproduction, and mood.

Hormones are distinct from neurotransmitters, which are chemicals used by the nervous system to send signals between neurons and are not typically released into the bloodstream for systemic regulation. Additionally, enzymes are proteins that catalyze biochemical reactions but do not have the systemic regulatory functions that hormones possess. Cytokines are involved in cell signaling, particularly in the immune system, but they are not classified as hormones and do not have the broad systemic effects associated with the secretions of the endocrine system.