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16 Cards in this Set
- Front
- Back
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What is the average age of epiphyseal fusion for girls and boys?
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- girls: 15 yrs old
- boys: 17-18 yrs old |
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Fastest growthrate occur in which of the following period?
- first year of life - second year of life - third year of life - between age 4 and puberty |
first year of life: 25cm per year
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List some hormones that regulates growth.
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- GH
- TH - sex hormone - insulin - glucocorticoids |
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What hormone is this?
- single chain peptide (191 AA) - genes located on chromosone 17) - transcription require pituitary transcriptional factor (Pit1) - not needed for fetal growth |
GH
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What are some direct effect of GH?
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- AA transport
- lipolysis - insulin resistance - nitrogen retention |
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What are some stimulators of GH synthesis? inhibitors?
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stimulators of GH synthesis
- GHRH - T3 - Ghrelin inhibitors of GH synthesis - cortisol inhibitor of GH release - somatostatin (SRIH) |
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How does ghrelin(28 AA peptide) affect growth?
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- secreted by gastric neuroendocrine cells and hypothalamus
- bind to GHSR in hypothalamus, pituitary, other brain centers - stimulates food intake |
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What are some defects in hypothalamic-pituitary-IGF1 axis that cause growth defect?
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1. hypothalamic dysfunction
- GHRH deficiency 2. pituitary dysfunction - GHRH receptor dysfunction - GH deficiency 3. GHR deficiency in body tissue (liver), abnormal GH signaling (JAK/STAT/MAPK) 4. defects in type 1 IGF receptor |
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Effect of TH on linear bone growth.
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- increase bone age
- increase growth rate - no change in adult height - permissive effect on GH secretion |
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Effect of glucocorticoids on linear bone growth.
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- decrease bone age
- decrease growth rate - decreased adult height - toxic effect on epiphysis, may not be correctable by GH and IGF therapy (lack of complete catch up growth) |
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Effect of gonadal steroids linear bone growth.
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- increase bone age
- increase growth rate - decreased adult height - enhance GH secretion - direct stimulation of IGF1 production |
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Name the hormone(s) responsible for growth from conception to birth.
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insulin
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Name the hormone(s) responsible for growth after birth.
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- GH
- TH - Sex hormone (after puberty) |
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Name the hormone(s) responsible for growth after puberty.
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- GH
- TH - Sex hormone |
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What the cause of short stature in this girl?
- pubertal delay - external stigmata - webbing of the neck - coarctation of aorta, valve problems - horshoe kidney - autoimmune disorder eg Hashimotos |
Turner syndrome (XO)
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What are some endocrine causes of short stature?
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- hypothyroidism
- GH deficiency - GH insensitivity (Laron syndrome) - IGF unresponsiveness - glucocorticoids excess - precocious puberty (early exposure to sex steroids) - psychosocial dewarfism |
