Neuroscience Fundamentals Practice Test 2025 - Complete Exam Preparation

Hormones are indeed the chemical messengers produced by endocrine glands that play a crucial role in regulating target cells or organs throughout the body. These substances are secreted directly into the bloodstream, allowing them to travel to various tissues and elicit specific physiological responses. Each hormone has a distinctive function and is involved in a wide range of bodily processes, including metabolism, growth, reproduction, and mood regulation.

In contrast, neurotransmitters are chemical messengers in the nervous system that transmit signals across synapses between neurons, rather than being released into the bloodstream. Cytokines are signaling molecules that mediate and regulate immunity, inflammation, and hematopoiesis, functioning primarily in the immune system, rather than being produced by endocrine glands. Peptides can indeed function as hormones (some hormones are peptides), but they are also involved in numerous other biological processes and are not exclusive to the endocrine system.

Thus, hormones uniquely characterize the regulatory role of chemical messengers produced by endocrine glands, connecting various physiological systems within the body.