Endokrina

Endokrina refers to the endocrine system, the collection of ductless glands and tissues that secrete hormones directly into the bloodstream. Hormones act as chemical messengers that regulate metabolism, growth, development, reproduction, and the maintenance of homeostasis. Unlike exocrine glands, which release substances through ducts, endocrine glands release hormones into the circulatory system for distant targets.

Key components include classic glands such as the hypothalamus, pituitary, pineal, thyroid, parathyroid, thymus, adrenal glands, pancreas, and the gonads (ovaries and testes). Hormones produced span several chemical classes, including peptides and proteins, steroids derived from cholesterol, and amines. In addition to these organs, other tissues such as adipose tissue, the gut, heart, and bone also secrete hormones and contribute to endocrine signaling, creating a broader network of regulation.

Regulation is primarily accomplished through feedback mechanisms, with the hypothalamus and pituitary often acting as central regulators. Hormone action depends on receptor presence and can be rapid or slow, influenced by timing and patterns such as circadian rhythms and pulsatile secretion.

Functions cover a wide range of physiological processes, including energy metabolism, calcium homeostasis, growth and development, reproductive function, stress response, and fluid balance. Disruptions in endocrine signaling can lead to disorders such as diabetes mellitus, thyroid disease, adrenal disorders, pituitary dysfunction, and gonadal abnormalities. Diagnosis typically involves hormone assays and imaging, while treatment may include hormone replacement, suppression, or lifestyle interventions.

Historically, endocrinology emerged in the late 19th and early 20th centuries, with foundational work by researchers such as Bayliss and Starling, establishing endocrine signaling as a distinct field.