1. Posterior Pituitary Gland MARISSA MIARA, DEVON PARODI, TAMARA NEBRIGIC - TABLE 4

2. Posterior Pituitary (neurohypophysis)  It is arguable that the pituitary gland is not a gland  Collection of axonal projections from hypothalamus that terminate behind the anterior pituitary gland  These axons release peptide hormones into the capillaries of the hypopyseal circulation  Hormones are synthesized by the hypothalamus then are stored in the neurosecretory vesicles before being secreted by the posterior pituitary into the blood stream  Stores and secretes oxytocin and vasopressin

3. Location  Posterior Pituitary (neurohypophysis) is located in the posterior lobe of the pituitary gland.  Attached to the hypothalamus by the infundibulum

4. Hormones  The posterior pituitary only secretes 2 hormones: Vasopressin and Oxytocin  Vasopressin:  also called arginine vasopressin (AVP) and antidiuretic hormone (ADH)  Acts on the collecting ducts of the kidneys to facilitate reabsorption of water into the blood- reducing the volume of urine formed  Deficiency of vasopressin leads to excessive loss of urine which causes Diabetes Insipidus  Oxytocin:  Acts on certain smooth muscles  Stimulates contractions of uterus during birth  Stimulates release of milk for baby  Usually given to mothers to hasten birth

5. Homeostasis and Feedback loops  Vasopressin keeps blood pressure at a constant rate, keeping all autonomic nervous systems functioning properly  Hypothalamus senses changes in the body and notifies the pituitary gland if vasopressin or oxytocin is needed  Oxytocin is one of the only hormones with a positive feedback loop.

6. Releasing Hormones and Glands  Hypothalamus makes and releases inhibiting hormones for posterior pituitary gland

7. Hypersecretion Conditions  Acromegaly- causes enlargement in the extremities of the body  Cushing’s Disease- Causes excessive amounts of cortisol to be excreted  Prolactinoma- Causes excess amounts of prolactin

8. Hyposecretion Conditions  Adult Growth Hormone Deficiency- Fails to produce Growth Hormone  Diabetes Insipidus- Passing dilute urine, increased thirst and urination.  Hypopituitanism- Failure of the pituitary gland to produce one or more hormones it normally produces.

9. Medical Treatment  Medications via injections, patches, pills, nasal spray  Surgery  Some are untreatable

10. Sources  www.varhormones.info/glands/pituitary_gland.aspx www.varhormones.info/glands/pituitary_gland.aspx  En.Wikipedia.org/wiki/posterior_pituitary  Emoryhealthcare.org/pituitary/treatments/index.html  www.hormone.org/disease-and-conditions/pituitary/overview www.hormone.org/disease-and-conditions/pituitary/overview  https://www.boundless.com/physiology/textbooks/boundless- anatomy-and-physiology-textbook/the-endocrine-system-16/the- pituitary-gland-hypophysis-155/the-posterior-pituitary-and- hormones-of-the-posterior-pituitary-787-9333/ https://www.boundless.com/physiology/textbooks/boundless- anatomy-and-physiology-textbook/the-endocrine-system-16/the- pituitary-gland-hypophysis-155/the-posterior-pituitary-and- hormones-of-the-posterior-pituitary-787-9333/  http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Pituitary.h tml http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Pituitary.h tml