Mamm Phys notes

Mamm Phys notes - Endocrinerelease~ blood TypesofHormones...

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Endocrine release~ hormones are released into interstittial tissues and circulate via blood Types of Hormones: 1. steroids~ derived from cholesterol lipid soluable include sex hormones (estrogen, testosteron, progesterone) sercreted by testies, ovaries, sex organs as well as cortisol and aldosterone and androgens which are secreted by the adrenal cortex. Cortisol is released in responce to stress and icreases blood glucose levels and aldosterone is released in responce to low blood vol/ pressure so that na conc. can increase in blood 2. Amines~ include thyroid hormones and catacholamines which are derived from tyrosine. Thyroid hormones are thyroxine (t4) and triiodothyroxine) catacholamines include epi, norepi and dopamine. amines arent lipid solouble so transduction pathway includes the Gi or Gs protein system which uses cAMP as second messanger. Problems associated with amine hormones are goiter, thyroid tumor, hypothyroidism, hyperthyroidism and graves disease. Hypothyroidism is when you have low levels of T4 and T3 and because of neg feedback loop the hypothalamus is secreting thyroid releasing hormone which acts on the anterior pituitary to releae thryroid stim hormone (so u have high levers of TSH and TRH) hyperthyroidism is the exact opposite. Problems associated with hypothyroidism is mental retardation, obessity. Graves disease is an autoimmune disease and is a case of hyperthyroidism. Symptoms of hyperthyroidism include wt loss, increased appitite, heat intolerance, fatigue. Goiter is swelling of the thyroid gland and is due to an increase in TSH receptors and a decrease in T3 and T4. Treatment for goiter is to give iodized salt in diet. Thyroid tumers can be cause by hyper or hypo thyroidism where treatment involved giving radioactive iodince to kill off the cells that over producing thyroid hormones. Catacholamines are lipid insoluable and thryoid hormones are lipid soluable meaning they can directly cross membrane and bind to nuclear and cytosolic receptors thereby altering gene expression~ slow long lasting affects. transduction pathway of amines is different because they are lipid insoable (like protein hormones) Pathway includes binding to B receptors for Gs pathway and binding to alpha receptors and M2 receptors when using Gi pathway. Gs Pathway~ hormones like EPi binds to membrane receptor which causes the 3 subunits of the G protein to dissacosiate and bind to GTP so now it is in active form and increase activity of adenalate cyclys. Adenalate cyclase takes ATP and turns it into cAMP which is the main secondary messanger. cAMP acts on PKA to phosphorolate proteins
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The Gi pathway of alpha and M2 receptors inhibits the activity of adenalate cyclase. To terminate the transduction pathway there are a few things that you can do:
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Mamm Phys notes - Endocrinerelease~ blood TypesofHormones...

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