The endocrine system consists of all the endocrine glands present in the human body.These glands, though lacking topographical and physical continuity, constitute a unitary system that is integrated in a harmonic way from the mutual interdependence and the presence of the hypothalamic-pituitary axis, which ensures the equilibrium of the whole system.
Endocrine glands make chemicals called hormones (endocrine hormones or incretin) which pass through the blood stream. They perform functions related to maintaining homeostasis of the organism as well as provide balance of bodily functions (despite external environment changes) and physical-chemical characteristics of its internal environment.
The major glands that make up the endocrine system include the pituitary gland, the pancreas, the thymus gland, the thyroid gland, the parathyroid and the adrenal glands.
The pituitary gland
The pituitary gland is an endocrine gland located in the cranium, more precisely, in a bone excavation of the body’s sphenoid bone known as “sella turcica“. Although it is small, weighing just over half a gram, it is the most important endocrine gland in the human body. In fact, the hormones secreted from it stimulate the activity of other endocrine glands (such as the thyroid and adrenal glands), which are essential for the performance of various activities in the body.
The pancreas is a gland that takes the shape of an elongated cone and is a part of the digestive system. It is involved in endocrine secretion (a process that entails secretion of products, hormones, directly into the bloodstream), as well as exocrine secretion (a process in which products are placed in a natural cavity in the body or released outside). Almost horizontally positioned, the pancreas is located in the upper abdomen, and transversely behind the stomach, at the level of the first two lumbar vertebrae.
The exocrine secretion, essential for the digestive process of food consumed, is carried out by small structures known as glandular acini, which are secreted into the intestine and pour through the Wirsung duct.The final product in the exocrine secretion is the pancreatic juice, which is a liquid that is formed by a set of enzymes (lipase, amylase, etc.) essential for digestion.
The endocrine secretion is performed by endocrine cells grouped in the islets of Langerhans. Endocrine cells are divided into alpha cells, beta cells and delta cells. the alpha cells are involved in secreting glucagon (the hyperglycaemic hormone); the beta cells are involved in secreting insulin (the hypoglycemic hormone); and finally, the delta cells are involved in secreting the hormone somatostatin, though which the activity of the alpha and beta cells can be monitored.
The thymus gland
The thymus is a gland located in the chest, in front of the trachea. Its main function is to ensure the maturation of T cells, which are a type of white blood cells that play a key role in the immune system. The thymus develops until reaching with the upper end of the thyroid and with the lower end of the fourth rib cartilage.
The thyroid gland
The thyroid, also known as the “thyroid gland”, is placed in correspondence to the border between the larynx and trachea, at the base of the anterior portion of the neck. Under constant control of ‘pituitary gland , the primary function of the thyroid is to produce and secrete thyroid hormones, which are ecessary for growth and development of the organism.
The parathyroid glands
The parathyroid glands ensure the production and the endocrine secretion of the parathyroid hormone (or parathormone), a particular hormone essential in the regulation of the metabolism of minerals (particularly calcium and phosphorus) within the organism. Located behind the thyroid gland, there are generally four parathyroid glands (or two pairs of parathyroid glands), however, there may also be five or six. Their name reflects their close relationship with the thyroid gland.
The adrenal glands
The adrenal glands are two small glands, one located on the upper end of each kidney. They weigh about 5 grams each and have a yellowish-brown color. Their function is to secrete hormones (aldosterone, cortisone, and cortisol) responsible for the performance of several physiological functions.
What function does the endocrine system serve?
The functionality of the endocrine system, whose operation and balance are guaranteed functional interdependence of the various glands and the presence of the hypothalamic-pituitary axis, is to ensure the supply of hormones in all the right quantities to the human body so that it can carry out all the necessary physiological processes.