Endocrine System

• Endocrine System are ductless glands that secrete different types of hormones and regulate metabolism, growth, and development.
• Hormones are a chemical substance that travel thru bloodstream
• Classic hormones (produced by specialized glands) are divided into 

  three  groups: low molecular, steroid hormones, polypeptidic and protein hormones
• Steroid Hormone Action diffuses through the plasma membrane of target cells and activates genes that result in the synthesis of new proteins
• Nonsteroid Hormone Action does not enter to the cell and hormone binds to a membrane receptor
• Glands are a cell or group of cells (tissue) that secretes fluids
• The hypothalamus is located inferior to the thalamus. It’s a major link between the nervous and the endocrine systems.
• The Pituitary Gland (The Hypophysis) considered as the ‘Maestro Gland’ because it releases various hormones that control all the major endocrine glands of the body.
• It’s formed of two anatomical and functional parts:

  1. The Adenohypophysis (Anterior Pituitary)
  2. The Neurohypophysis (Posterior Pituitary)
• Growth Hormone (GH): essential for the growth and development of bones, muscles, and other organs. It also enhances protein synthesis, decreases the use of glucose, and promotes fat destruction.
• Adrenocorticotropin (TRŌ pun) (ACTH): essential for the growth of the adrenal cortex.
• Thyroid-Stimulating Hormone (TSH):  essential for the growth and development of the thyroid gland.
• Follicle-Stimulating Hormone (FSH):  is a gonadotropic hormone.
• Luteinizing Hormone (LH):  is a gonadotropic hormone stimulating the development of corpus luteum in the female ovarian follicles and the production of testosterone in the male.
• Prolactin (PRL):  stimulates the development and growth of the mammary glands and milk production during pregnancy.
• Melanocyte-stimulating hormone (MSH): regulates skin pigmentation and promotes the deposit of melanine in the skin after exposure to sunlight
• Antidiuretic Hormone (ADH):  stimulates the reabsorption of water by the renal tubules. Hyposecretion of this hormone can result in diabetes insipidus. 
• Oxytocin:  stimulates the uterus to contract during labor, delivery, and parturition.  A synthetic version of this hormone, used to induce labor, is called Pitocin. It also stimulates the mammary glands to release milk.
• The thyroid gland consists of numerous spherical structures called the thyroid follicles and it is also unique in that it’s the only endocrine gland in the body that stores its hormones outside the cells. A vital role in metabolism and regulates the body’s metabolic processes.
• Calcitonin:  influences bone and calcium metabolism;  maintains a homeostasis of calcium in the blood plasma
• Thyroxine (T4) and triodothyronine (T3):  essential to BMR – basal metabolic rate
• The Parathyroid Gland each one is surrounded by its own capsule and 4 in number
• The two pairs of parathyroid glands are located on the dorsal or back side of the thyroid gland. They secrete parathyroid (PTH) which plays a role in the metabolism of phosphorus.
• The Adrenal (Suprarenal) Glands - the right gland is pyramidal in shape, whereas the left is crescentic in shape.
• Cortisol:  regulates carbohydrate, protein, and fat metabolism;  has an anti-inflammatory effect;  helps the body cope during times of stress
• Aldosterone:  essential in regulating electrolyte and water balance
• Corticosterone:  like cortisol, it is a steroid;  influences potassium and sodium metabolism
• Androgens:  several hormones including testosterone;  they promote the development of secondary sex characteristics in the male.
• Dopamine is used to treat shock.
• Epinephrine is also called adrenalin. It is often used to counteract an allergic reaction.
• Norepinephrine, like epinephrine, is released when the body is under stress. It creates the underlying influence in the fight or flight response
• The thymus gland has two lobes, and is part of the lymphatic system.
• • The pancreas is a mixed gland
  • The islets of the pancreas produce hormones
• Alpha cells facilitate the breakdown of glycogen to glucose. This elevates the blood sugar.
• Beta cells secrete the hormone insulin, which is essential for the maintenance of normal blood sugar levels.
• Delta cells suppress the release of glucagon and insulin.
• Pineal Gland are found on the third ventricle of the brain and secretes melatonin
• Melatonin: communicates information about environmental lighting to various parts of the body
• Serotonin: a neurotransmitter that regulates intestinal movements and affects appetite, mood, sleep, anger, and metabolism.
• Hormones of the Testes are interstitial cells of testes are hormone-producing