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21 Cards in this Set
- Front
- Back
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Normal time frame of organ growth plateau?
Brain? Reproductive organs? Lymphoid tissue? |
organs- 4 and again between 13 and 17
Brain- 8 yrs sizewise, but developmental wise 25 Reproductive organs at birth and again age 15-20 lymphoid- 13 yrs |
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Environmental influences on growth?
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Nutrition and general health,
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Describe the influence of thyroid hormones on growth and what controls them
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Mediates and is necessary for the production and action of GH
- necessary for action of IGF - required for growth of bone |
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What is the official name of GH and IGF?
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GH= somatotropin tropin = growth
IGF= somatomedin medin= mediator |
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What hormone and from where inhibits GH?
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Somatostatin or GHIH from hypothalamus
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What hormone does fetal growth require?
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more on IGF-II and does not require GH
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What does GH do to...
a. body mass in general b. proteins? c. AA's, RNA, DNA d. glucose |
a. Stimulates growth of lean body mass
• Encourages production of proteins • Increases AA transport • Increases RNA transduction • Increases DNA transcription - blocks uptake of glucose (resists insulin) |
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What does GH do to...
a. Ca b. Na c. K d. Cell size e. fat |
. - increases Ca absorption and Na and K retention
Causes cell hypertrophy and hyperplasia - mobilizes FFA and reduces adipose tissue |
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Growth Hormone does what to...
a. bone b. IGF-I (somatomedin) |
Increases bone mass
• Length if preclosure of epiphyseal plate • Thickness throughout life • Causes increased secretion of IGF-I (somatomedin) |
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Increased levels of IGF does what to GH?
What is half life of GH? What problem does this cause? |
– Increased IGF inhibits GH secretion (negative feedback)
• Half life of 6 to 20 minutes – Pulsatile secretion makes it hard to get accurate measure |
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GH can be secreted in times of what?
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a. hypoglycemia
b. decreased FFA c. decreased protein intake d. low caloric intake e. anxiety excitement f. exercise g. deep sleep stages II and IV |
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What do androgens and estrogens do to GH levels?
What activities naturally have the highest levels of GH in the body? |
exentuate the things that stimulate GH release
- exercise and deep sleep highest GH |
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GH inhibitors?
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a. aging
b. obesity c. Somatostatin (released in response to glucose and FAs) d. IGF-1 e. GH f. REM sleep (THIS IS WRONG) g. elevated FFA, glucose, cortisol |
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IGF-1 secreted by what things?
How does it differ in its effects from GH's effects? |
many tissues including liver and osteoblasts
- IGF- promotes glucose uptake and opposes lypolysis and has a 20 hr half life |
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what is especially effect in causing closure of epiphysial plates?
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estrogen has a greater effect on growth rate than testosterone but overall cause by increased production of androgen and estrogens
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Panhypopituitarism defined?
If occurs before full growth? |
Loss or decreased secretion of all anterior pituitary hormones
- small stature of normal proportions (dwarfism) lack of hormones needed to go through puberty (no sexual maturation) - more aging |
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Specific decrease in GH shows what different signs than panhypopituitarism?
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small stature but sexual maturation occurs
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• GH levels high but IGF levels low could indicate what?
Seen in? |
GH receptor insensitivity
- laron dwarves |
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GH normal but IGF is decreased do to what?
What group do we see normal of GH and IGF but still short |
IGF-I receptor insensitivities could be indicated in African pygmies who have normal levels of GH and IGF-1
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MC form of dwarfism?
inheritance? How can you tell? |
Achondroplasia
- FGHR3- stimulates fibroblast growth hormone receptor which blocks calcification matrix - AD - shortened proximal limb bones |
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Hypersecretion of GH shows what chronically (balam)
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- hyperglycemic
- ketosis |
