antidiuretic hormone

Examples of antidiuretic hormone in the following topics:

• The Posterior Pituitary

  • The posterior pituitary secretes two important endocrine hormones—oxytocin and antidiuretic hormone.
  • These axons release peptide hormones into the capillaries of the hypophyseal circulation.
  • Oxytocin is one of the few hormones that create a positive feedback loop.
  • Antidiuretic hormone (ADH, also known as vasopressin), the majority of which is released from the supraoptic nucleus in the hypothalamus.
  • Identify the location of the posterior pituitary and the hormones associated with it

• Regulation of Urine Concentration and Volume

  • Antidiuretic hormone (ADH) is produced by the pituitary gland to control the amount of water that is reabsorbed through the collecting ducts.
  • There are a few complex systems involved in regulating blood volume and urine production, such as the intricate renin–angiotensin system, and the simpler anti-diuretic hormone (ADH) feedback system.
  • ADH is a hormone secreted from the posterior pituitary gland in response to increased plasma osmolarity (i.e., increased ion concentration in the blood), which is generally due to an increased concentration of ions relative to the volume of plasma, or decreased plasma volume.
  • Describe how regulating the amount of water excreted in urine is an essential component of homeostasis that is regulated by the antidiuretic hormone (ADH)

• Circumventricular Organs

  • As a result, neurons located in circumventricular organs can directly sense the concentrations of various compounds, particularly peptide hormones, in the bloodstream without the need for specialized transport systems that move those compounds across the blood-brain barrier.
  • These organs secrete or are sites of action of a variety of different hormones, neurotransmitters, and cytokines.
  • The secretory organs are responsible for secreting hormones and glycoproteins into the peripheral vascular system using feedback from both the brain environment and external stimuli.
  • Posterior pituitary: Stores and releases oxytocin and vasopressin, also known as antidiuretic hormone, produced in the hypothalamus.

• Production of Dilute and Concentrated Urine

  • The hormones ADH (Anti-diuretic hormone, also known as vasopressin) and aldosterone play a major role in this balance.
  • These areas project to the supraoptic nucleus and paraventricular nucleus, which contain neurons that secrete the antidiuretic hormone vasopressin from their nerve endings in the posterior pituitary.
  • Thus, there will be an increase in the secretion of antidiuretic hormone that causes fluid to be retained by the kidneys and urine output to be reduced.
  • The system then stimulates zona glomerulosa of the adrenal cortex which, in turn, secretes the hormone aldosterone.
  • This hormone stimulates the reabsorption of sodium ions from distal tubules and collecting ducts.

• Overview of Endocrine Glands

  • Two hormones—oxytocin and antidiuretic hormone (ADH)—are produced and released this way.
  • The anterior pituitary is involved in sending hormones that control all other hormones of the body.
  • Communication between the hypothalamus and the anterior pituitary occurs through hormones (releasing hormones and inhibiting hormones) that are produced by the hypothalamus and delivered to the anterior pituitary via a portal network of capillaries.
  • The hormones then diffuse from this secondary plexus into the anterior pituitary, where they initiate the production of specific hormones by the anterior pituitary.
  • These hormones increase the metabolic activity of the body‘s cells.

• Nephron, Parts, and Histology

  • It is regulated by the neuroendocrine system by hormones such as antidiuretic hormone, aldosterone, and parathyroid hormone.
  • Unlike the other components of the nephron, its permeability to water is variable depending on a hormone stimulus to enable the complex regulation of blood osmolarity, volume, pressure, and pH.
  • Many other hormones will induce other important changes in the distal convoluted tubule that fulfill the other homeostatic functions of the kidney.
  • The collecting duct is similar in function to the distal convoluted tubule and generally responds the same way to the same hormone stimuli.
  • The osmolarity of fluid through the distal tubule and collecting duct is highly variable depending on hormone stimulus.

• Overview of the Urinary System

  • Many hormones involved in homeostasis will alter the permeability of these tubules to change the amount of water that is retained by the body.
  • The kidneys play a very large role in human osmoregulation by regulating the amount of water reabsorbed from the glomerular filtrate in kidney tubules, which is controlled by hormones such as antidiuretic hormone (ADH), renin, aldosterone, and angiotensin I and II.

• Absorption of Monosaccharides, Amino Acids, Dipeptides, Tripeptides, Lipids, Electrolytes, Vitamins, and Water

  • Glucose, amino acids, fats, and vitamins are absorbed in the small intestine via the action of hormones and electrolytes.
  • The enzymes enter the small intestine in response to the hormone cholecystokinin, which is produced in the small intestine in response to the presence of nutrients.
  • The hormone secretin also causes bicarbonate to be released into the small intestine from the pancreas in order to neutralize the potentially harmful acid coming from the stomach.
  • Electrolyte balance is regulated by hormones, generally with the kidneys flushing out excess levels.
  • In humans, electrolyte homeostasis is regulated by hormones such as antidiuretic, aldosterone, and parathyroid hormone.

• Chemistry of Hormones

  • There are three classes of hormones: peptide hormones, lipid hormones, and monoamine hormones.
  • Some peptide hormones contain carbohydrate side chains  and are termed glyco-proteins, such as the follicle-stimulating hormone.
  • All peptide hormones are hydrophilic and are therefore unable to cross the plasma membrane alone.
  • Eicosanoids are also lipid hormones that are derived from fatty acids in the plasma membrane.
  • Unlike other hormones, eicosanoids are not stored in the cell—they are synthesized as required.

• Mechanisms of Hormone Action

  • As a result, hormonal signaling is elaborate and hard to dissect.
  • The reaction of the target cells may then be recognized by the original hormone-producing cells, leading to a down-regulation in hormone production.
  • Transport of the hormone to the target cells, tissues, or organs.
  • Nuclear hormone receptors are activated by a lipid-soluble hormone such as estrogen, binding to them inside the cell.
  • Lipid-soluble hormones can cross the plasma membrane.