 Dear students, in this topic, we shall take an overview of the endocrine glands of vertebrates. The vertebrates have a large number of endocrine glands and tissues that produce hormones. Most of the hormones are produced by only one endocrine gland, which is located at a specific site. However, some hormone-like substances, for example, prostaglandins and leukotrienes, are produced by most or all tissues of the body. And some hormones are produced by more than one specific tissues of the body. We shall take an overview of the vertebrate endocrine glands and the hormones which they produce. First, most important, neuroendocrine gland is the hypothalamus. Hypothalamus produces seven hormones which affect the anterior pituitary gland. These hormones are the tropic hormones and have two types of effects. Four hormones have stimulatory effects and three hormones have inhibitory effects on rays of hormones from the pituitary gland. These stimulatory hypothalamic hormones include the carticotropin releasing hormone, CRH, growth hormone releasing hormone, gonadotropin releasing hormone, GNRH and thyrotropin releasing hormone, TRH. These hormones affect the anterior pituitary gland to produce the respective hormones. The hypothalamic inhibitory hormones include three hormones, MSH inhibiting hormone, which is called MIH, prolactin inhibiting hormone and somatostatin. These hormones inhibit the secretion of hormones from anterior pituitary. These hormones which are inhibited include the melanocyte stimulating hormone, prolactin and growth hormone. Dear students, the anterior pituitary gland produces four types of tropic hormones and three other hormones which are non-tropic in action. Tropic hormones are those hormones which act on other endocrine glands and cause them to produce their own hormones. While non-tropic hormones are those which act directly on the tissues and produce their effects. The pituitary gland has two lobes. The anterior lobe produces four tropic hormones. These hormones include the luteinizing hormone, which acts on the gonads, especially the ovaries, follicle stimulating hormone that also acts on the gonads and causes them to produce the male and female sex hormones. The third hormone is the thyroid stimulating hormone, TSH, also called thyrotropin. It stimulates the thyroid gland to produce its hormone. The fourth hormone is the adenocarticotropic hormone or ACTH that stimulates the release of cortico steroids from the adenocortex. The anterior pituitary gland also produces three non-tropic hormones. These include the growth hormone prolectin and melanocyte stimulating hormones. They promote growth, promote production of milk and stimulate melanin pigment respectively. Dear students, the posterior lobe of pituitary gland also produces two hormones. These hormones are anti-diuretic hormone and oxytocin. Dear students, next endocrine gland is the thyroid gland. Thyroid gland has two types of glandular cells. The follicular cells which produce two hormones thyroxine and triiodothyronine. While the para follicular cells of thyroid produce one hormone that is called calcitonine. The next endocrine gland of vertebrates is the parathyroid gland. This produces one hormone which is called paratharmon. Dear students, the next endocrine gland we will discuss is adenyl gland. This is a dual gland. It contains adenyl cortex and adenyl medulla. Adenyl cortex produces two types of hormones which are mineralocorticoids and glucocorticoids. Apart from this, it also produces many other hormones. Most of the types of gland we are talking about produce more hormones but we are discussing the major hormones. So major hormones which are adenyl cortex have aldosterone which is mineralocorticoid and glucocorticoids which have three types of hormones. Cartisol, cartisone and carticosterone. They are produced from adenyl cortex. Adenyl medulla produces two very important hormones which are epinephrine and nor epinephrine. They are called catecholamines. Dear students, pancreas is a dual gland. It has exocrine part that produces the digestive pancreatic juice but it also has eyelets of langerhans which are endocrine in their function. They produce two hormones insulin and glucagon. The next gland is the pineal gland. Penial gland produces a hormone which is called melatonin and this melatonin is very important in circadian rhythms. Dear students, gonads in addition to producing gametes also act as endocrine tissues. The testis produce two types of hormones testosterone and in heaven from two types of glandular cells, latic cells and cell-to-lie cells. The ovaries produce two major hormones in females. These are estrogens. The major estrogen is the estradiol and the progesterone. Dear students, the placenta which develops during the fetal development also produces many hormones. The two major hormones produced by placenta are corionic gonadotropin and placental lactogen. Dear students, heart is a pumping organ but its atrium also produces an important hormone which is called atrial natriuretic factor that controls blood volume and pressure. Dear students, the gastrointestinal tract also produces many hormones. These hormones include cholecystokinin, chymodenin, gastrin, secretin, substance p, and motilin. Many of these regulate the secretions of digestive juices and enzymes. Dear students, some hormones and hormone-like substances are produced by most or all tissues of the body. These hormones include leukotrienes, prostacycline, prostaglandins, and thrombocenes. These control various nucleotide formation and cyclic AMPs and cyclic GMPs. The hormones which are produced by more than one selected type of tissues include endorphins, epidermal growth factors, fibroblast growth factor, nerve growth factor, and somatomedin. Dear students, from all this list we can conclude that some glands are distinct and are easily identifiable. However, a large number of endocrine tissues are not distinct and are found embedded in the organs which have quite different functions than the endocrine functions. That is why the identification and discovery of endocrine glands has been a challenging task.