Anterior pituitaryA major organ of the endocrine system, the anterior pituitary (also called the adenohypophysis or pars anterior) is the glandular, anterior lobe that together with the posterior lobe (posterior pituitary, or the neurohypophysis) makes up the pituitary gland (hypophysis). The anterior pituitary regulates several physiological processes, including stress, growth, reproduction, and lactation. Proper functioning of the anterior pituitary and of the organs it regulates can often be ascertained via blood tests that measure hormone levels.
Pituitary adenomaPituitary adenomas are tumors that occur in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas. Pituitary adenomas represent from 10% to 25% of all intracranial neoplasms and the estimated prevalence rate in the general population is approximately 17%. Non-invasive and non-secreting pituitary adenomas are considered to be benign in the literal as well as the clinical sense; however a recent meta-analysis (Fernández-Balsells, et al.
HypopituitarismHypopituitarism is the decreased (hypo) secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain. If there is decreased secretion of one specific pituitary hormone, the condition is known as selective hypopituitarism. If there is decreased secretion of most or all pituitary hormones, the term panhypopituitarism (pan meaning "all") is used. The signs and symptoms of hypopituitarism vary, depending on which hormones are undersecreted and on the underlying cause of the abnormality.
Endocrine diseaseEndocrine diseases are disorders of the endocrine system. The branch of medicine associated with endocrine disorders is known as endocrinology. Broadly speaking, endocrine disorders may be subdivided into three groups: Endocrine gland hypofunction/hyposecretion (leading to hormone deficiency) Endocrine gland hyperfunction/hypersecretion (leading to hormone excess) Tumours (benign or malignant) of endocrine glands Endocrine disorders are often quite complex, involving a mixed picture of hyposecretion and hypersecretion because of the feedback mechanisms involved in the endocrine system.
Cushing's diseaseCushing's disease is one cause of Cushing's syndrome characterised by increased secretion of adrenocorticotropic hormone (ACTH) from the anterior pituitary (secondary hypercortisolism). This is most often as a result of a pituitary adenoma (specifically pituitary basophilism) or due to excess production of hypothalamus CRH (corticotropin releasing hormone) (tertiary hypercortisolism/hypercorticism) that stimulates the synthesis of cortisol by the adrenal glands.
Hypothalamic–pituitary–gonadal axisThe hypothalamic–pituitary–gonadal axis (HPG axis, also known as the hypothalamic–pituitary–ovarian/testicular axis) refers to the hypothalamus, pituitary gland, and gonadal glands as if these individual endocrine glands were a single entity. Because these glands often act in concert, physiologists and endocrinologists find it convenient and descriptive to speak of them as a single system. The HPG axis plays a critical part in the development and regulation of a number of the body's systems, such as the reproductive and immune systems.
Endocrine systemThe endocrine system is a 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 vertebrates, the hypothalamus is the neural control center for all endocrine systems. In humans, the major endocrine glands are the thyroid gland, parathyroid gland, pituitary gland, pineal gland, the testes (male), ovaries (female), and the adrenal glands. The hypothalamus, pancreas, and thymus also function as endocrine glands, among other functions.
Adrenal insufficiencyAdrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones. The adrenal glands, also referred to as adrenal cortex normally secretes glucocorticoids (primarily cortisol), mineralocorticoids (primarily aldosterone), and androgens. These hormones are important in regulating blood pressure, electrolytes, and metabolism as a whole. Deficiency of these hormones leads to symptoms ranging from abdominal pain, vomiting, muscle weakness and fatigue, low blood pressure, depression, mood and personality changes (in mild cases) to organ failure and shock (in severe cases).
Hypothalamic–pituitary–thyroid axisThe hypothalamic–pituitary–thyroid axis (HPT axis for short, a.k.a. thyroid homeostasis or thyrotropic feedback control) is part of the neuroendocrine system responsible for the regulation of metabolism and also responds to stress. As its name suggests, it depends upon the hypothalamus, the pituitary gland, and the thyroid gland. The hypothalamus senses low circulating levels of thyroid hormone (Triiodothyronine (T3) and Thyroxine (T4)) and responds by releasing thyrotropin-releasing hormone (TRH).
Thyroid hormonesFile:Thyroid_system.svg|thumb|upright=1.5|The [[thyroid]] system of the thyroid hormones [[triiodothyronine|T3]] and T4References used in image are found in image article in Commons:[[Commons:File:Thyroid system.png#References]].
AcromegalyAcromegaly is a disorder that results in excess growth of certain parts of the human body. It is caused by excess growth hormone (GH) after the growth plates have closed. The initial symptom is typically enlargement of the hands and feet. There may also be an enlargement of the forehead, jaw, and nose. Other symptoms may include joint pain, thicker skin, deepening of the voice, headaches, and problems with vision. Complications of the disease may include type 2 diabetes, sleep apnea, and high blood pressure.
HypothalamusThe hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamus is located below the thalamus and is part of the limbic system. In the terminology of neuroanatomy, it forms the ventral part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is the size of an almond.
CortisolCortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the zona fasciculata of the adrenal cortex in the adrenal gland. It is produced in other tissues in lower quantities. It is released with a diurnal cycle and its release is increased in response to stress and low blood-glucose concentration. It functions to increase blood sugar through gluconeogenesis, to suppress the immune system, and to aid in the metabolism of fat, protein, and carbohydrates.
Adrenal cortexThe adrenal cortex is the outer region and also the largest part of an adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones. It is also a secondary site of androgen synthesis. The adrenal cortex comprises three main zones, or layers that are regulated by distinct hormones as noted below. This anatomic zonation can be appreciated at the microscopic level, where each zone can be recognized and distinguished from one another based on structural and anatomic characteristics.
Cushing's syndromeCushing's syndrome is a collection of signs and symptoms due to prolonged exposure to glucocorticoids such as cortisol. Signs and symptoms may include high blood pressure, abdominal obesity but with thin arms and legs, reddish stretch marks, a round red face due to facial plethora, a fat lump between the shoulders, weak muscles, weak bones, acne, and fragile skin that heals poorly. Women may have more hair and irregular menstruation. Occasionally there may be changes in mood, headaches, and a chronic feeling of tiredness.
HyperprolactinaemiaHyperprolactinaemia is the presence of abnormally high levels of prolactin in the blood. Normal levels average to about 13 ng/mL in women, and 5 ng/mL in men, with an upper normal limit of serum prolactin levels being 15-25 ng/mL for both. When the fasting levels of prolactin in blood exceed this upper limit, hyperprolactinemia is indicated. Prolactin (PRL) is a peptide hormone produced by lactotroph cells in the anterior pituitary gland. PRL is involved in lactation after pregnancy and plays a vital role in breast development.
Thyroid-stimulating hormoneThyroid-stimulating hormone (also known as thyrotropin, thyrotropic hormone, or abbreviated TSH) is a pituitary hormone that stimulates the thyroid gland to produce thyroxine (T4), and then triiodothyronine (T3) which stimulates the metabolism of almost every tissue in the body. It is a glycoprotein hormone produced by thyrotrope cells in the anterior pituitary gland, which regulates the endocrine function of the thyroid.
Thyroid hormone resistanceThyroid hormone resistance (also resistance to thyroid hormone (RTH), and sometimes Refetoff syndrome) describes a rare syndrome in which the thyroid hormone levels are elevated but the thyroid stimulating hormone (TSH) level is not suppressed, or not completely suppressed as would be expected. The first report of the condition appeared in 1967. Essentially this is decreased end organ responsiveness to thyroid hormones. A new term "impaired sensitivity to thyroid hormone" has been suggested in March 2014 by Refetoff et al.
GigantismGigantism (γίγας, gígas, "giant", plural γίγαντες, gígantes), also known as giantism, is a condition characterized by excessive growth and height significantly above average. In humans, this condition is caused by over-production of growth hormone in childhood, resulting in people up to in height. It is a rare disorder resulting from increased levels of growth hormone before the fusion of the growth plate which usually occurs at some point soon after puberty. This increase is most often due to abnormal tumor growths on the pituitary gland.
Adrenal glandThe adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex which produces steroid hormones and an inner medulla. The adrenal cortex itself is divided into three main zones: the zona glomerulosa, the zona fasciculata and the zona reticularis. The adrenal cortex produces three main types of steroid hormones: mineralocorticoids, glucocorticoids, and androgens.
