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28 Cards in this Set
- Front
- Back
hyper- or hypo- thyroidism?
- Irritability • Anxiety • Heat intolerance • Insomnia • Eye tearing • Dyspnea • Heart palpitations • Increased appetite, but weight loss • Diarrhea • Increased defecation • Sweating • Hair loss • Amenorrhea • Muscle fatigue • Tremors |
Hyperthyroidism
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hyper- or hypo- thyroidism?
• Memory loss • Depression • Cold intolerance • Hoarseness • Periorbital edema • Peripheral edema • Chest pain • Decreased appetite, but weight gain • Constipation • Dry skin • Coarse hair • Menorrhagia • Muscle fatigue |
Hypothyroidism
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What is the active form of thyroid hormone?
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T3
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TSH is released from the _______________
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anterior pituitary
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What cleaves T4 to active T3?
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D1 & D2
(type 1 & 2 deiodonase) |
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So, T4 is preferentially released from the thryroid gland. Explain the steps that occur for it to produce a thyroid hormone response
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T4 converted to T3 via D2
↓ T3 enters cell via TH Receptor ↓ T3 interacts with retinoid X receptor (RXR) ↓ Binds to thyroid-hormone responsive gene ↓ Changes in critical proteins, thus, inducing a response |
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D1 converts T4 --> T3 in what tissues?
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Liver
Kidney Thyroid |
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D2 converts T4 --> T3 in what tissues?
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Skeletal Muscle
Cardiac Muscle Hypothalamus Pituitary |
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What hormone produces these effects?
• normal growth and metabolism • overall oxygen utilization • basal metabolic rate • carbohydrate metabolism • protein metabolism • lipid metabolism • thermogenesis |
Thyroid hormone
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What form of Ca++ is biologically active?
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Ionized Ca++
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Name the hormone:
Binding of Ca++ to its receptor: - inhibits cAMP - stimulates PLC **unique situation in which an increase in [Ca] does NOT lead to exocytosis** |
PTH
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PTH is secreted in response to (2)
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Absolute [Ca]
Rate of fall of [Ca] (When [Ca] is getting low, PTH is released) |
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PTH release:
increases/decreases bone resorption increases/decreases loss of calcium in urine increases/decreases absorption of calcium in intestines |
increases bone resorption
decreases loss of calcium in urine increases absorption of calcium in intestine |
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How does low-dose PTH increase bone formation?
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↑ β-catenin which is needed for bone formation
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KNOW THIS TABLE
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This hormone has an indirect effect on the formation of Vit. D:
Promotes absorption of Ca++ and phosphate in intestines |
PTH
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How does PTH affect both osteoclasts and osteoblasts to ultimately increase bone resorption?
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(+) osteoblast
production of M-CSF and RANK ligand to promote production and activity of osteoclasts (-) osteoblast production of OPG, which blocks the interaction of RANK ligand and its receptor |
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How does PTH increase intestinal absorption of Ca++ and Phosphorus?
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↑ 1α hydroxylase activity In PT cells
↓ ↑ synthesis of 1,25 (OH)2-Vit. D |
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This hormone increases the reabsorption of Ca++ in the distal tubule and increases Ca++ ATPase and Ca+/Na+ exchanger activity on the basolateral membrane
(Net result is increased serum Ca++) |
PTH
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Ca2+ in the lacunae is in equilibrium with plasma Ca2+ but, under the action of
_______, Ca2+ is taken up by the osteocytes, transported to the surface osteoblasts which pump the Ca2+ into the extracellular fluid, thus raising plasma Ca2+ concentrations. |
PTH
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What is the primary mediator of hypercalcemia associated with malignacy?
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Parathyroid Hormone Related Protein
(PTHrP) **Binds to same receptor as PTH – elicits the same response as PTH** |
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This hormone:
↓ bone resoprtion; ↓ plasma Ca++ |
Calcitonin
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This hormone:
↑ intestinal Ca++ absorption; ↑ bone resorption; ↑ plasma Ca++; (-) PTH |
Vit. D
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Growth hormone, IGF-1, Insulin, Sex steroids (estrogens/androgens) all _____ bone formation
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increase bone formation
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Thyroid hormones, cytokines (IL-1) and Gluccocorticoids all _____ bone resorption
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increase bone resorption
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High Yield!!
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Reduced estrogen has what effect on osteoblasts?
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Basically, it inhibits their formation by ↓preosteoblasts
It also ↑osteoclasts |
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This is probably important
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