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23 Cards in this Set
- Front
- Back
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Which (T3 or T4) has a high affinity for the thyroid hormone rececptor
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T3 has a high affinity for the TH receptor
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MIT + DIT = ?
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T3
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DIT + DIT = ?
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T4
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what enzyme adds iodine to the tyrosine residues in thyroglobulin to creat MIT and DIT on the apical membrane
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Thyroperoxidase
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What enzyme catalyzes the joining of MIT and DIT
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thyroperoxidase
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Where does the H2O2 come from that is needed for attachment of iodine to the thyroglobulin?
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Thyroid oxidase
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Where is iodine stored in the tyroid
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Iodine is brought into the colloid via a Na+ symporter and stored in the colloid
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D1, D2, and D3 deiodinases are involved in activating what
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removal of an iodine from T4 to make T3
they can also inactivate T3/T4 by removing it down to T2 |
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T3 and T4 circulate bound to what
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Thyroxin Binding Globule, Transthretin, and Albumin
All are produced in liver |
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Problem with the liver could lead to what
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Circulating concentration of Thyroid hormone because the transport proteins for TH are made in the liver
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Majority of TH is bound or free?
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Bound
Free is the active form |
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Out line the release of TH
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Hypothalamus produces TRH onto the pituitary which releases TSH onto the Thyroid
Thyroid produces T3 and T4 |
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Define the feedback for the thyroid
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T3 and T4 feedback to both the pituitary and to the hypothalamus to down regulate or up regulate the thyroid production
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What disease is associated with Hyperthyroidism?
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Graves disease = autoimmune
TSH receptor Ab's stimulate thyroid gland |
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What disease is associated with hypothyroidism?
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Hashimoto's Thyroiditis (autoimmue)
Ab's against thyroid cells |
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PTH is secreted in response to ?
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decreased ionic [Ca2+]
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How is PTH secreted
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secreted as a preprohormone
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Ca2+ inhibits the release of PTH from:
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Cheif cells
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what happens when Ca2+ concentration decreases?
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you have decreased binding of Ca2+ to its receptor on the parathyroid cells.
When bound this Ca2+ acts as an inhibitor. Decreased [ ] = removal of this inhibitor signal = PTH secreted |
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What does PTH do and what structures does it target
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goal is to increase Ca2+ [ ] in the blood
Targets Bones, Kidney, & GI |
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What effect does PTH have on the kidney
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increases reabsorption of Ca2+
decreases Phos reabsorption Activated 1alpha hydroxylase =increases vitamin D production decreases bicarb reabsorption |
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What effect does this stimulation of 1alpha hydroxylase have?
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increased active vitamin D indirectly enhances the absorption of Ca2+ in the GI
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Are there PTH receptors on osteoclasts?
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No just on the osteoblasts
this works indirectly by stimulating molecules which streamline the osteoclast precursor into full fledged osteoclasts. |
