The endocrine system is a chemical messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In humans, the major endocrine glands are the adrenal glands. In vertebrates, the hypothalamus is the neural control center for all endocrine systems; the study of the endocrine system and its disorders is known as endocrinology. Endocrinology is a branch of internal medicine. A number of glands that signal each other in sequence are referred to as an axis, such as the hypothalamic-pituitary-adrenal axis. In addition to the specialized endocrine organs mentioned above, many other organs that are part of other body systems have secondary endocrine functions, including bone, liver and gonads. For example, the kidney secretes the endocrine hormone erythropoietin. Hormones can be amino acid complexes, eicosanoids, leukotrienes, or prostaglandins; the endocrine system can be contrasted to both exocrine glands, which secrete hormones to the outside of the body, paracrine signalling between cells over a short distance.
Endocrine glands have no ducts, are vascular, have intracellular vacuoles or granules that store their hormones. In contrast, exocrine glands, such as salivary glands, sweat glands, glands within the gastrointestinal tract, tend to be much less vascular and have ducts or a hollow lumen; the word endocrine derives via New Latin from the Greek words ἔνδον, endon, "inside, within," and "crine" from the κρίνω, krīnō, "to separate, distinguish". The human endocrine system consists of several systems. Several important feedback systems are mediated via pituitary. TRH – TSH – T3/T4 GnRH – LH/FSH – sex hormones CRH – ACTH – cortisol Renin – angiotensin – aldosterone leptin vs. insulin Endocrine glands are glands of the endocrine system that secrete their products, directly into interstitial spaces and absorbed into blood rather than through a duct. The major glands of the endocrine system include the pineal gland, pituitary gland, ovaries, thyroid gland, parathyroid gland and adrenal glands; the hypothalamus and pituitary gland are neuroendocrine organs.
There are many types of cells that comprise the endocrine system and these cells make up larger tissues and organs that function within and outside of the endocrine system. HypothalamusAnterior pituitary glandPineal glandPosterior pituitary glandThyroid gland Follicular cells of the thyroid gland produce and secrete T3 and T4 in response to elevated levels of TRH, produced by the hypothalamus, subsequent elevated levels of TSH, produced by the anterior pituitary gland, which further regulates the metabolic activity and rate of all cells, including cell growth and tissue differentiation. Parathyroid gland Epithelial cells of the parathyroid glands are richly supplied with blood from the inferior and superior thyroid arteries and secrete parathyroid hormone. PTH acts on bone, the kidneys, the GI tract to increase calcium reabsorption and phosphate excretion. In addition, PTH stimulates the conversion of Vitamin D to its most active variant, 1,25-dihydroxyvitamin D3, which further stimulates calcium absorption in the GI tract.
Adrenal glands Adrenal cortex Adrenal medullaPancreas Alpha cells Beta cells Delta cells F CellsOvaries Granulosa cells Testis Leydig cells Adrenal glands The fetal adrenal cortex can be identified within four weeks of gestation. The adrenal cortex originates from the thickening of the intermediate mesoderm. At five to six weeks of gestation, the mesonephros differentiates into a tissue known as the gonadal ridge; the gonadal ridge produces the steroidogenic cells for the adrenal cortex. The adrenal medulla is derived from ectodermal cells. Cells that will become adrenal tissue move retroperitoneally to the upper portion of the mesonephros. At seven weeks of gestation, the adrenal cells are joined by sympathetic cells that originate from the neural crest to form the adrenal medulla. At the end of the eighth week, the adrenal glands have been encapsulated and have formed a distinct organ above the developing kidneys. At birth, the adrenal glands weight eight to nine grams and are 0.5% of the total body weight.
At 25 weeks, the adult adrenal cortex zone develops and is responsible for the primary synthesis of steroids during the early postnatal weeks. Thyroid gland. One part is from the thickening of the pharyngeal floor, which serves as the precursor of the thyroxine producing follicular cells; the other part is from the caudal extensions of the fourth pharyngobranchial pouches which results in the parafollicular calcitonin-secreting cells. These two structures are apparent by 16 to 17 days of gestation. Around the 24th day of gestation, the foramen cecum, a thin, flask-like diverticulum of the median anlage develops. At 24 to 32 days of gestation the median anlage develops into a bilobed structure. By 50 days of gestation, the medial and lateral anlage have fused together. At 12 weeks of gestation, the fetal thyroid is capable of storing iodine for the production of TRH, TSH, free thyroid hormone. At 20 weeks, the fetus is able to implement feedback mechanisms for the production of thyroid hormones.
During fetal development, T4 is the major thyroid hormone being produced while triiodothyronine and its inactive derivative, reverse T3, are not detected until the third trimester. Parathyroid glands A lateral and ventral view of an embryo showing the third and fourth parathyroid glands du
The Pedra da Boca State Park is a state park in the state of Paraíba, Brazil. It contains a group of unusual rocky outcrops surrounded by cerrado vegetation. One of the rocks has a large collection of prehistoric rock paintings, is a site of religious services for devotees of Our Lady of Fátima; the Pedra da Boca State Park is in the municipality of Araruna, Paraíba, in the Curimataú Oriental microregion. It has an area of 157.3 hectares on the border. It is 170 kilometres from João Pessoa, the state capital, 22 kilometres from the town of Araruna, it lies in the foothills between the Serra de Araruna. The park is in the basin of the Calabouço River, an intermittent tributary of the Curimataú River that forms the border between Paraíba and Rio Grande do Norte and is an important source of water for the local population; the Pedra da Boca State Park was created by state governor José Targino Maranhão by decree 20.889 of 7 February 2000. Soon after the park was created the land was expropriated and families living in the park were compensated.
The Köppen climate classification is Bsh: semi-arid and dry, with a short rainy season in the autumn and winter. Annual rainfall is 800 to 1,100 millimetres. Temperatures range from 25 to 27 °C; the vegetation is in the caatinga biome. Vegetation includes primitive trees, with small remnants of montane forest, it has been affected by extraction of wood, cattle grazing and agriculture. The water resources of the Calabouço basin have been badly managed; the riparian forest is devastated, the soil is impoverished and the river bed is silted. There is significant biodiversity, with an estimated 21 species of reptiles and amphibians, 16 of mammals and 125 of plants; the main species of flora are Anadenanthera peregrina, Myracrodruon urundeuva, Syagrus comosa, Ficus species, Hymenaea courbaril, Tocoyena brasiliensis, Ziziphus joazeiro, Libidibia ferrea, Mimosa acustitipula, Mimosa tenuiflora, Chloroleucon foliolosum, Bromelia laciniosa, Cereus jamacaru, Bauhinia cheilanta, Combretum leprosum, Erythrina velutina, Guazuma ulmifolia, Handroanthus chrysotrichus, Talisia esculenta, Sisalana perrine, Spondias tuberosa, Pilosocereus gounellei, Aspidosperma pyrifolium, Melocactus bahiensis, Schinopsis brasiliensis, Spondias tuberosa, Croton sincorensis and Pilosocereus squamosus.
The park contains a set of rocks of porphyritic granite composition, with traces of gneisses and quartzites. The outcrops have rounded faces and extensive vertical corrugations from the ground to their summits. "Pedra da Boca" is the name of a rock formation about 336 metres high with a cavity formed by erosion which resembles a giant toad about to gulp something. Other dramatic outcrops include the Pedra da Caveira, Pedra do RN, Pedra do Carneiro and Pedra do Letreiro; the Pedra do Letreiro known as the Pedra da Santa, has a large collection of hieroglyph rock paintings of the northeast tradition, attributed to the Tarairiu and Paiacu people who lived in the region, members of the great Kiriri nation known as Tapuias. The park receives about 1,200 visitors per month in the high season of summer; the park attracts scholars and visitors who love nature and adventure sports. There is an ecological trail that takes about three hours for active people, with some climbing involved. Use of ropes is required in some places.
This visits all the formations, passes a spring of water, specimens of forest and a variety of birds and reptiles. Visitors may practice rappelling and climbing on the rocks as well as mountain biking and paragliding; as of 2007 there was a shortage of infrastructure and of an effective plan to preserve the environment from damage by visitors. The park lacked signs and educational material to make the visitors aware of the importance of conservation. On the 13th of every month in May, thousands of devotees from the region and from further afield come to open air masses; the politician Celso Lisboa built an altar in the cave of the Pedra da Santa dedicated to Our Lady of Fatima. It became impossible to use this place due to bees living on the huge rock, for a period outdoor masses were held by the chapel near the park; the state government built the Sanctuary of Our Lady of Fatima near the Pedra da Santa in the form of a Greek arena with a capacity of about 5,000 and facilities that include bathrooms, cafeteria and accommodation for the pilgrims
Stafford Mills is an historic textile mill complex located on County Street in Fall River, Massachusetts, USA. Founded in 1872, it is a well-preserved late-19th century textile complex, typical of the mills built in Fall River during its period of most rapid growth, it is noted in particular for its exceptionally fine Romanesque brick office building. The complex was added to the National Register of Historic Places in 1983; the Stafford Mills complex is located east of downtown Fall River, on 7 acres at the northeast corner of Quarry and County Streets. It consists of a series of interconnected buildings, most built at different times; the two principal mill buildings built of Fall River granite. The buildings are somewhat unusual in not having towers, a common mill feature. Set in the mill yard between these two structures are attached picker and boiler houses built of granite; the office building stands at the center of the southern end of the millyard. The Stafford Mills company was incorporated in 1870 with Foster H. Stafford as its first president.
The two mills were built in 1872 and 1888, the office building was added in 1892. The company produced print cloths, operated until 1929 when it was closed. Today, the complex is occupied by a variety of a discount furniture store; the intersection of County Street, Pleasant Street and Quarry Street in front of the mill is known as Stafford Square. Stafford Mills had a major fire on January 13, 2020 displacing many of the tenant companies and damaging the structure. National Register of Historic Places listings in Fall River, Massachusetts List of mills in Fall River, Massachusetts