Pituitary Gland

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Pituitary Gland. Posterior Pituitary ( Neurohypophysis ). The posterior lobe of the pituitary gland that is the release point of antidiuretic hormone (ADH) and oxytocin (page 368).
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Pituitary Gland Posterior Pituitary (Neurohypophysis) The posterior lobe of the pituitary gland that is the release point of antidiuretic hormone (ADH) and oxytocin (page 368). Stimulation of milk ejection (milk letdown): Milk is initially secreted into small sacs within the mammary gland called alveoli, from which it must be ejected for consumption or harvesting. Mammary alveoli are surrounded by smooth muscle (myoepithelial) cells which are a prominant target cell for oxytocin. Oxytocin stimulates contraction of myoepithelial cells, causing milk to be ejected into the ducts and cisterns. Stimulation of uterine smooth muscle contraction at birth: At the end of gestation, the uterus must contract vigorously and for a prolonged period of time in order to deliver the fetus. During the later stages of gestation, there is an increase in abundance of oxytocin receptors on uterine smooth muscle cells, which is associated with increased "irritability" of the uterus (and sometimes the mother as well). Oxytocin is released during labor when the fetus stimulates the cervix and vagina, and it enhances contraction of uterine smooth muscle to facilitate parturition or birth. In cases where uterine contractions are not sufficient to complete delivery, physicians and veterinarians sometimes administer oxytocin ("pitocin") to further stimulate uterine contractions - great care must be exercised in such situations to assure that the fetus can indeed be delivered and to avoid rupture of the uterus. Oxytocin(neurohypophysis) Stimulation of uterine smooth muscle contraction at birth: At the end of gestation, the uterus must contract vigorously and for a prolonged period of time in order to deliver the fetus. During the later stages of gestation, there is an increase in abundance of oxytocin receptors on uterine smooth muscle cells, which is associated with increased "irritability" of the uterus (and sometimes the mother as well). Oxytocin is released during labor when the fetus stimulates the cervix and vagina, and it enhances contraction of uterine smooth muscle to facilitate parturition or birth. Antidiuretic hormone (ADH)(neurohypophysis) The single most important effect of antidiuretic hormone is to conserve body water by reducing the loss of water in urine. A diuretic is an agent that increases the rate of urine formation. Injection of small amounts of antidiuretic hormone into a person or animal results in antidiuresis or decreased formation of urine, and the hormone was named for this effect. Disorder: The major sign of either type of diabetes insipidus is excessive urine production. Some human patients produce as much as 16 liters of urine per day! If adequate water is available for consumption, the disease is rarely life-threatening, but withholding water can be very dangerous. Hypothalamic diabetes insipidus can be treated with exogenous antidiuretic hormone. Anterior Pituitary Hormones (Adenohypophysis) Adenohypophysis, occupies the prime place because, through the secretion of various hormones, it controls the functioning of certain other endocrine glands, namely, the adrenal cortex, the thyroid, and the gonads. In addition, hormones from the anterior pituitary influence the growth and metabolism of the organism through direct action on skeletal, muscular, and other tissues. The pituitary maintains control over the various target organs by a feedback mechanism which is sensitive to circulating levels of hormones from the target organs. Adreno = adrenalcortio = cortisoltropic = suffix meaning a "turn or deviation from normal" Adrenocorticotropic (ACTH)(adenohypophysis) ACTH's principal function is to stimulate the cortex (outer layer) of the adrenal glands (located near the kidneys) to secrete a group of steroid hormones called glucocorticoids. Glucocorticoid hormones control the body's use of sugar and also help regulate biological functions during stressful moments. Cortisol is the major natural glucocorticoid. You may have heard cortisol called the “stress” hormone since it is true that people produce greater levels of it under significant stress and especially during a “fight or flight” reaction. The adrenal gland, which is responsible for producing cortisol, does create it at varied levels throughout the day. You’ll tend to have the most available cortisol in the morning and it wanes as the day progresses. Cushing DiseaseATCH disorder Symptoms include rapid weight gain, particularly of the trunk and face with sparing of the limbs (central obesity). A common sign is the growth of fat pads along the collar bone and on the back of the neck (buffalo hump) and a round face often referred to as a "moon face". Follicle-stimulating hormone (FSH)(adenohypophysis) FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body. FSH and Luteinizing hormone (LH) act synergistically in reproduction. Luteinizing hormone(adenohypophysis) In women, LH helps regulate the menstrual cycle and egg production (ovulation). The level of LH in a woman's body varies with the phase of the menstrual cycle. It increases rapidly just before ovulation occurs, about midway through the cycle (day 14 of a 28-day cycle). This is called an LH surge. Luteinizing hormone and follicle-stimulating hormonelevels rise and fall together during the monthly menstrual cycle. In men, LH stimulates the production of testosterone, which plays a role in sperm production Luteinizing Hormone“Lutes in the bag”Bag = ovaries and testiesLute= ova and sperm Growth Hormone
  • Effects of growth hormone on the tissues of the body can generally be described as anabolic (building up). Like most other protein hormones, GH acts by interacting with a specific receptor on the surface of cells.
  • Increased height during childhood is the most widely known effect of GH.
  • In addition to increasing height in children and adolescents, growth hormone has many other effects on the body:
  • Increases calcium retention, and strengthens and increases the mineralization of bone
  • Increases muscle mass through sarcomere hyperplasia
  • Promotes lipolysis
  • Increases protein synthesis
  • Stimulates the growth of all internal organs excluding the brain
  • Plays a role in fuel homeostasis
  • Reduces liveruptake of glucose
  • Promotes gluconeogenesis in the liver
  • Contributes to the maintenance and function of pancreatic islets
  • Stimulates the immune system
  • Thyroid stimulating gland (TSH) TSH actually comes from one of the master brain-glands called the “pituitary gland”. It is the hormone that stimulates thyroid hormone production. The hormones released from the thyroid gland (T4 and T3) once responding to stimulation by TSH are the ones the regulate bodily metabolism. The two major thyroid hormones are called "thyroxine" (T4) and "triiodothyronine" (T3). Their purpose is to regulate the rate of metabolism in every cell of the body. These hormones also regulate protein, fat, and carbohydrate metabolism, affecting how human cells use energetic compounds. They also stimulate vitamin metabolism. Numerous physiological and pathological stimuli influence thyroid hormone synthesis. Thyroid hormone leads to heat generation in humans. Graves disease Graves disease is an autoimmune disorder that involves over activity of the thyroid gland (hyperthyroidism). Hallmarks of the condition are bulging eyes (exophthalmos), heat intolerance, increased energy, difficulty sleeping, diarrhea, and anxiety. Prolactin Prolactin (PRL) or Luteotropic hormone (LTH) is a peptide hormone discovered by Dr. Henry Friesen, primarily associated with lactation. In breastfeeding, the act of an infant sucking the nipple stimulates the production of prolactin, which fills the breast with milk via a process called lactogenesis, in preparation for the next feed. Oxytocin, another hormone, is also released, which triggers milk let-down. Adrenal cortex hormonesGlucocorticoids Glucocorticoids (GC) are a class of steroid hormones that bind to the glucocorticoid receptor (GR), which is present in almost every vertebrate animal cell. The name glucocorticoid (glucose + cortex + steroid) derives from their role in the regulation of the metabolism of glucose, their synthesis in the adrenal cortex and their steroidal structure. GCs are part of the feedback mechanism in the immune system that turns immune activity (inflammation) down. They are therefore used in medicine to treat diseases that are caused by an overactive immune system, such as allergies, asthma, autoimmune diseases and sepsis. Gluco = glucosecortic = steriodoid = resembling (steriod) Mineralocorticoids(aldosterone) Mineralocorticoids are a class of steroid hormones characterised by their similarity to aldosterone and their influence on salt and water balances. Aldosterone is a hormone that increases the reabsorption of sodium and water and the release (secretion) of potassium in the kidneys. This increases blood volume and, therefore, increases blood pressure. Aldosterone acts directly on the kidney to decrease the rate of sodium-ion excretion, and to increase the rate of potassium-ion excretion MineralsMinerals can be found in water and soil and therefore in root plants and animals
  • Trace Minerals
  • The trace minerals are iron, zinc, copper, selenium, iodine, fluorine and chromium.
  • Major Minerals
  • The major minerals are sodium, potassium, calcium, phosphorus, magnesium, manganese, sulphur, cobolt and chlorine.
  • Function
  • Minerals serve three roles:
  • They provide structure in forming bones and teeth
  • They help maintain normal heart rhythm, muscle contractility, neural conductivity, and acid-base balance
  • They help regulate cellular metabolism by becoming part of enzymes and hormones that modulate cellular activity
  • Mineral = mineralcortic = steriodoid = resembling (steriod) Thryoxine (T4)Triiodothyronine (T3) The two major thyroid hormones are called "thyroxine" (T4) and "triiodothyronine" (T3). Their purpose is to regulate the rate of metabolism in every cell of the body. These hormones also regulate protein, fat, and carbohydrate metabolism, affecting how human cells use energetic compounds. They also stimulate vitamin metabolism. Numerous physiological and pathological stimuli influence thyroid hormone synthesis. Thyroid hormone leads to heat generation in humans. Thyroid HormoneCalcitonin Calcitonin lowers the concentration of calcium in the blood when it rises above the normal value. This hormone has the opposite effect of parathyroid hormone(parathormone). Parathyroid hormone
  • Writing a job description for parathyroid hormone is straightforward: if calcium ion concentrations in extracellular fluid fall below normal, bring them back within the normal range. In conjunction with increasing calcium concentration, the concentration of phosphate ion in blood is reduced. Parathyroid hormone accomplishes its job by stimulating at least three processes:
  • Mobilization of calcium from bone
  • Enhancing absorption of calcium from the small intestine
  • Suppression of calcium loss in urine
  • Sex hormones Sex hormones The differences between female hormones and male hormones may not be as specific as you might think. The definition of a hormone is a chemical substance produced by an endocrine gland that has a specific effect on the activities of other organs in the body. The major female and male hormones can be classified as estrogens or androgens. Both classes of male and female hormones are present in both males and females alike, but in vastly different amounts. Estrogens are the sex hormones produced primarily by a female's ovaries that stimulate the growth of a girl's sex organs, as well as her breasts and pubic hair, known as secondary sex characteristics. Estrogens also regulate the functioning of the menstrual cycle. The Importance of EstrogenEstrogens are important in maintaining the condition of the vaginal lining and its elasticity, and in producing vaginal lubrication. They also help preserve the texture and function of a woman's breasts. In men, estrogens have no known function. An unusually high level, however, may reduce sexual appetite, cause erectile difficulties, produce some breast enlargement, and result in the loss of body hair in some men. Androgens are sex hormones produced primarily by a male's testes, but are also produced in small amounts by the female's ovaries and the adrenal gland, an organ found in both sexes. Androgens help trigger the development of the testes and penis in the male fetus. They jump start the process of puberty and influence the development of facial, body and pubic hair, deepening of the voice, and muscle development, the male secondary sex characteristics. Epinephrine Definition: Also known as adrenalin, epinephrine is a naturally occurring hormone. During the fight-or-flight response response, the adrenal gland releases epinephrine into the blood stream, along with other hormones like cortisol, signaling the heart to pump harder, increasing blood pressure, opening airways in the lungs, narrowing blood vessels in the skin and intestine to increase blood flow to major muscle groups, and performing other functions to enable the body to fight or run when encountering a perceived threat. GlucagonPancreatic homrone Glucose Metabolism Energy is required for the normal functioning of the organs in the body. Many tissues can also use fat or protein as an energy source but others, such as the brain and red blood cells, can only use glucose. Glucagon is secreted when the blood glucose levels fall below normal values. Glucagon stimulates the liver to convert glycogen to glucose, which causes the blood glucose level to rise. Glucagon also stimulates the production of glucose from amino acids and lactic acid in the liver. Glucagon stimulates the release of fatty acids from adipose tissue. When blood glucose levels rise, the secretion of glucagons decreases as part of the negative feedback system. InsulinPancreatic hormone Insulin is a natural hormone which controls the level of the sugar glucose in the blood. Insulin allows cells to use glucose for energy. Cells cannot utilize glucose without insulin. Excess glucose builds up in the bloodstream, increasing the risk of diabetes. Glucose is the body's primary source of fuel. Insulin enables the body cells to take glucose from the bloodstream. The cells might use glucose for production of energy if required, or it is sent to the liver to preserve it, in the form of glycogen. The failure to make insulin or insufficiency of insulin is termed as Diabetes mellitus.
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