Final answer:
The chemical substances secreted by endocrine glands are hormones, which serve as chemical messenger molecules. These substances circulate in the bloodstream and have widespread impacts on the body by binding to specific receptors on target cells. Hormones are essential for regulating bodily functions and maintaining homeostasis.
Step-by-step explanation:
Chemical Substances Secreted by Endocrine Glands
The chemical substances secreted by the endocrine glands are known as hormones. These hormones are chemical messenger molecules that are released into the bloodstream and travel to target cells throughout the body. Hormones bind to receptors on these target cells, which can be situated in distant organs, triggering a range of physiological responses. These responses are critical for maintaining homeostasis, facilitating growth, development, and coordinating stress response. For example, the adrenal glands produce epinephrine and norepinephrine, which help regulate the body's response to stress, while the thyroid gland secretes thyroid hormones that control metabolic rates.
Hormones contrast with neurotransmitters, which operate over shorter distances and have localized effects. By comparison, hormones have widespread effects on various cells that possess the necessary receptors, and their actions are typically slower to exhibit but tend to be longer lasting.
The endocrine system includes several glands such as the pancreas, which produces insulin and glucagon to regulate blood glucose levels, and the anterior pituitary, thymus, adrenal cortex, and gonads, each secreting hormones that orchestrate a myriad of bodily functions.