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14 Cards in this Set
- Front
- Back
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what are two enzymes in the process of making T3 and T4 (on the apical side of the thyroid cell)
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TPO and THOX2
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what is the form of thyroid hormone that affects the cell it enters
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T3 is the form that actually enters the nucleus to affect transciption and protein synthesis
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what converts T4 to T3
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D2
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what converts T4 --> rT3
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D3
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what does D3 do
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convert T4 to rT3 and T3 to T2 inside the affected cell
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what are the effects of thyroid hormone
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it basically does everything
normal growth and metabolism overall oxygen utilization basal metabolic rate carbohydrate metabolism protein metabolism lipid metabolism thermogenesis |
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where is calcitonin released from and what is the function in humans
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thyroid C cells (parafollicular cells), and the function is unknown but in animals it decrease bone resorption
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what alters the level of PTH
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level of [Ca] and the rate of change of [Ca]
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decrease in β-catenin causes what?
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increase in bone formation (PTH binds and inhibits the formation which then allows bone to form)
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how does serotonin affect bone formation
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Serotonin produced by the gut binds to one of its receptors (Htrb1) on osteoblasts – results in inhibition of cyclin production. Cyclins are involved in cell proliferation, so end result is decreased proliferation of ostoblasts and reduced bone formation.
Serotonin produced in brainstem binds to one of its receptors (Htr2c) in the ventromedial hypothalamus – results in decreased production of epinephrine. The resultant decrease in sympathetic tone, reduced activation of beta 2 adrenergic receptor on osteoblast. End result in increase in cyclin production leading to increase in osteoblast proliferation, and decrease in osteoblast production of RANKL which is needed for osteoclastogenesis…therefore reduced bone resorption. Remember: serotonin does not cross the blood/brain barrier |
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what doest PTH do to the bone
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increase resorption on Ca and P
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what does PTH do to the kidney
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increase Ca resorption and P EXCRETION
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what does PTH do to the intestines
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increase P and Ca absorption
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specifically, how does PTH affect osteoblasts
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Parathyroid hormone (PTH) acts on PTH/PTH-related protein (PTHrP) receptors on precursors of osteoblasts to increase the production of macrophage colony-stimulating factor (M-CSF) and RANK (receptor activator of nuclear factor қB) ligand and to decrease the production of osteoprotegerin (OPG). M-CSF and RANK ligand stimulate the production of osteoclasts and increase the activity of mature osteoclasts by binding to the receptor RANK. OPG blocks the interaction of RANK ligand and RANK
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