Hormonsystems

Hormonsystems refer to the networks of glands and cells that produce and regulate hormones, coordinating physiology through chemical signaling. Hormones are released into the bloodstream and act on distant targets, complementing the nervous system in maintaining homeostasis and guiding growth, development, and reproduction.

The major components include endocrine glands such as the hypothalamus, pituitary, thyroid, parathyroid, adrenal glands, pancreas, and gonads, as well as pineal and other tissues that secrete hormones. Additional organs—such as the stomach, intestines, adipose tissue, kidneys, and heart—also contribute hormonal signals. Hormones are broadly categorized as peptides or proteins, steroids, and amines.

Hormones influence target cells by binding to receptors. Peptide and amine hormones typically bind surface receptors and trigger signaling cascades, while steroid and thyroid hormones enter cells and regulate gene transcription. This diversity allows rapid responses or longer-term changes in cellular activity and metabolism.

Regulation of hormone secretion relies on feedback mechanisms and central control by the hypothalamus and pituitary gland. The autonomic nervous system, circadian rhythms, nutritional status, and stress can modulate release, ensuring coordinated activity across organ systems.

Functions of the hormonal systems include metabolism, growth and development, reproduction, fluid and electrolyte balance, and responses to stress. They regulate energy use, immune function, and tissue maintenance. Prominent examples are insulin and glucagon, cortisol, thyroid hormones, adrenaline, and sex steroids.

Dysfunctions arise from hypo- or hypersecretion, gland failure, or hormone resistance. Treatments may involve hormone replacement, synthesis inhibitors, or receptor-targeted therapies to restore balance.