Human Endocrine Glands And Hormones — a labelled NEET Biology diagram with a definitions lexicon.
Human Endocrine Glands and Hormones Labelled parts: Hypothalamus, Pituitary gland, Pineal gland, Thyroid gland, Thymus gland, Adrenal cortex, Adrenal medulla, Testis, Ovary, Pancreas, Anterior pituitary, Posterior pituitary, Parathyroid glands, GnRH, CRH, TRH, T3, T4, Calcitonin, Thymosins, Cortisol, Aldosterone, Androgens, Melatonin, ADH, Oxytocin, PTH, Estrogen, Progesterone, Insulin, Glucagon, Adrenaline, Noradrenaline, Testosterone, Inhibin. Gonadotropin-releasing hormone is a peptide hormone secreted by the hypothalamus that stimulates the pituitary gland to release FSH and LH. FYI: GnRH secretion is pulsatile, and its release pattern is critical for the normal reproductive cycle. This hormone, secreted by the parafollicular cells (C cells) of the thyroid gland, lowers blood calcium levels by promoting calcium deposition in bones. FYI: Unlike PTH, calcitonin's effect on calcium is generally weaker and is primarily involved in preventing hypercalcemia. These are cytokines secreted by thymic epithelial cells that play a role in the maturation and selection of T lymphocytes (T cells) in the thymus. FYI: The thymus is the primary site for T cell maturation, and thymosins are crucial for maintaining thymic function. It is a major glucocorticoid hormone secreted by the adrenal cortex that regulates metabolism, immune response, and blood pressure. FYI: Cortisol is often referred to as the 'stress hormone' because it is released in response to stress, helping to maintain blood glucose levels. A class of steroid hormones, primarily derived from adrenal and gonadal sources, that promote male secondary sexual characteristics. They are crucial for the development and maintenance of male reproductive tissues. FYI: Testosterone is the most potent and clinically significant androgen, responsible for the development of male secondary sexual characteristics. A hormone secreted by the pineal gland that regulates circadian rhythms and sleep-wake cycles. Its levels fluctuate with light exposure, influencing the body's internal clock. FYI: Melatonin secretion is inhibited by bright light, which is the primary mechanism by which light regulates the sleep cycle. A peptide hormone secreted by the beta cells of the pancreatic Islets of Langerhans. It lowers blood glucose levels by promoting the uptake of glucose by cells, especially muscle and adipose tissue. FYI: Insulin action is characterized by the translocation of GLUT4 glucose transporters to the cell membrane in muscle and adipose tissues. A peptide hormone secreted by the alpha cells of the pancreatic Islets of Langerhans. It raises blood glucose levels by stimulating the liver to break down stored glycogen (glycogenolysis) and synthesize glucose (gluconeogenesis). FYI: Glucagon and insulin act antagonistically; high glucose levels suppress glucagon release, while low glucose levels stimulate it. Also known as epinephrine, it is a catecholamine hormone released by the adrenal medulla. It mediates the 'fight or flight' response by increasing heart rate, blood pressure, and blood glucose. FYI: Adrenaline acts on beta-adrenergic receptors, leading to increased cardiac output and bronchodilation. Also known as norepinephrine, it is a catecholamine hormone released by sympathetic nerve endings and the adrenal medulla. Its primary action is to increase peripheral vascular resistance and blood pressure. FYI: Noradrenaline is a potent vasoconstrictor, making it crucial for maintaining blood pressure during stress. The most abundant and potent androgen, primarily produced by the Leydig cells in the testes. It is responsible for the development of male secondary sexual characteristics and spermatogenesis. FYI: Testosterone levels are regulated by the Hypothalamic-Pituitary-Gonadal (HPG) axis, specifically by LH and FSH. A glycoprotein hormone secreted by the Sertoli cells in males and the granulosa cells in females. Its primary function is to exert negative feedback on the secretion of Follicle-Stimulating Hormone (FSH). FYI: Inhibin levels rise as sperm production or follicular development progresses, thereby regulating FSH secretion.