Endocrine System
Along with the nervous system, the endocrine system is responsible for the regulation of all of the body functions and may have different properties at various stages of life. The glands of the endocrine system are ductless, secreting their products (hormones) directly into the circulatory system. An exception to this is the pancreas which is both an endocrine and an exocrine gland. Since hormones reach all parts of the body but have varying effects on organs and tissues, these organs and tissues must have different sensitivities to the hormonal influence.
| Hormone: | a substance produced in one part of the body and transported to another part(s) where it performs some function(s); hormones must act in extremely small quantities and cannot be a food; water is not a hormone |
| Target Organ: | the organ affected by a hormone |
| Endocrine Gland | Hormone | Target Organ and Effect |
| Neurohypophysis
(part of Pituitary) |
ADH (anti-diuretic hormone, vasopressin) | regulates water retention by the kidney |
| Oxytocin | acts on smooth muscles of reproductive systems; promotes uterine contraction at childbirth and ejection of milk during breastfeeding | |
| Adenohypophysis
(part of Pituitary) |
HGH (human growth hormone) | regulates growth of the entire body |
| PRL (prolactin) | stimulates the mammary glands to produce milk | |
| TSH (thyroid stimulating hormone) | stimulates the thyroid to produce its own hormones | |
| ACTH (adenocorticotropic hormone) | signals the adrenal cortex to produce steroids | |
| FSH (follicle stimulating hormone) | stimulate maturation of the ovum in the ovary and release of the ovum from the follicle | |
| LH (luteinizing hormone) | same functions as FSH |
|
| MSH (melanocyte stimulating hormone) | darkens skin by stimulating melanocytes in the epidermis | |
| Thyroid | TH (thyroid hormone or thyroxine) | increases basic metabolic rate throughout the body |
| Calcitonin | regulates calcium metabolism in young individuals | |
| Parathyroid | PH (parathyroid hormone) | regulates blood calcium levels |
| Pancreas | Insulin | stimulates the absorption of sugar into the tissues from the blood; promotes the formation of glycogen from sugar in the liver |
| Glucagon | stimulates the conversion of glycogen to sugar in the liver and the release of sugar into the blood | |
| Adrenal Glands | Corticosteroids | released by the adrenal cortex; some effects include regulating blood volume, reducing inflamation, and regulation of mineral uptake by the blood |
| Epinephrine and Norepinephrine | stimulates sympathetic nervous system and prime the body for "fight or flight" | |
| Ovaries | Estrogen | maintains reproductive organs and secondary sex characteristics; works as feedback to the pituitary |
| Progesterone | causes the uterus to prepare for pregnancy | |
| Testes | Testosterone | maintains reproductive organs and secondary sex characteristics |
| Pineal Gland | Melatonin | regulates the circadian cycle and prepares the body for sleep |