The endocrine system, involved in coordinating the activities of tissues throughout the body, acts by means of hor- mones. Hormones, made of amino acids or steroids, are released from endocrine cells at specific times and in precise amounts to act on target organs, often at some distance from their site of release.
Hormones usually act by binding with special receptor sites on or inside target cells. Endocrine organs (often called endocrine glands) secrete only into the bloodstream. Endocrine hormones affect the nervous system, and many endocrine organs are stimulated or inhibited by nerve cells. The hypothalamus of the brain has an intimate connection with the chief organ of the endocrine system, the pituitary.
This means that the endocrine and nervous systems share control of body functions: the nervous system usually controls activities occurring rapidly or in the short term, while the endocrine system controls slow or long-term changes. The organs involved in the male endocrine system are the pituitary, pineal, thymus, thyroid, parathyroids, adrenals, pancreatic islets, and testes. The testes produce hormones that control sexual function and secondary sexual characteristics.
The organs involved in the female endocrine system include the pituitary, pineal, thymus, thyroid, parathyroids, adrenals, pancreatic islets, ovaries, and placenta (during pregnancy). The ovaries produce hormones that control sexual function and secondary sexual characteristics.
The endocrine organs (or endocrine glands) secrete hormones that regulate growth. metabolism, sexul maturation, and other important body functions.
The pituitary gland (hypophysis) is a very small organ lying immediately below the hypohalamus of the brain. weighs only about V ounce (0.5 gram), but plays a very important role in the control of endocrine gland function throughout the body.
The pituitary gland is divided into anterior and posterior lobes (the adenohypophysis and neurohypophysis, respectively). The different types of cells, which produce anterior lobe contains many growth hormone, prolactin, follicle-stimulating hormone, lutein- izing hormone, thyroid-stimulating hormone, adrenocorticotrophic hormone, and melanocyte-stimulating hormone.
The poste lobe contains oxytocin and antidiuretic hormones, produced in the hypothalamus and transported to the pituitary within nerve fibers.
Description: The pancreas is an elongated gland lying behind the stomach. s large head is framed by the C-shaped loop of the duodenum, while its tail touches the spleen. The pancreas plays a role in both the digestive and endocrine systems The endocrine function of the pancreas is hormonal and is involved in the regulation of glucose mobilization and storage.
The two pancreatic hormones responsible for these functions are glucagon and insulin, respectively. These two hormones are pro- duced in special cell types within many tiny spherical clumps of pancreatic panereatic sue, tissue, which are known as the panereatic slets or the islets of Langerhans.
Within the islets of Langerhans, the alpha cells secrete glucagon, which elevat bod sugar; beta cells secrete insulin, which affects the metabolism of fats, protein s, and carbohydrates: and delta cells secrete somatostatin, which can inhibit the release of both glucagon and insulin.