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Hormones involved in bone formation:
- Insulin
- IGF-1
- Estrogen
- Testosterone
- Calcitonin
- GH
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Hormones involved in Reabsorption of bone are:
- Parathyroid hormones
- Thyroid hormones
- Cortisol
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Parathyroid hormone, Cortisol and Thyroid hormones all play what role in bone development how?
reabsoption
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GH, Insulin, IGF-1, Testosterone, Estrogen, Calcitonin are involved in bone development in what way?
formation
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Where are the parathyroid glands located?
adjacent to the thyroid gland
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The parathyroid glands are smaller or larger than the thyroid gland?
smaller
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How many parathyroid glands does each person have?
4 glands
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What do the parathyroid glands secrete?
parathormone and parathyrin
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Parathormone and parathyrin are produced by what glands?
parathyroid glands
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PTH stands for
parathyrin
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the abbreviation for parathyrin is:
PTH
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Wht is parathyrin or parathyromone secreted?
decrease in Ca conc.
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A decrease in ca concentration causes what glandular reponse?
release of parathyrin ot parathyormone
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What are the actions of PTH?
- reabsorption fo bone
- formation of Vit. D
- renal tubular absorption of Ca
- decreased excretion of Ca
- decreased reabsorption of K
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What hormone causes:
Reabsorption of bone
Renal tubular absorption of Ca
formation of Vit. D
deceased excretion fo Ca
decreased reabsorption of K?
PTH
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What do osteoblasts do?
build bone
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What bone cells build bone?
Osteoblasts
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What are osteocytes?
osteoblasts within bone matrix
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What are osteoblast that are trapped inbone matrix called?
Osteocytes
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Osteoclasts do what?
break down bone
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Which bone cell breaks down bone?
Osteoclasts
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Osteoclasts are stimulated by what hormone?
cortisol
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Cortisol has what stimulus on bone cells?
It stiulates Osteoclasts to break down bone
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If Calcium farises above homeostatic levels what gland and hormone corrects this imbalance?
Thyroid gland releases Calcitonin
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When Ca falls below homeostatic set points what gland and hormone return them to normal levels?
Prathyroid gland and PTH
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PTH has what effect on blood calcium levels?
raises them
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Calcitonin has what effect on blood Ca levels?
lowers them
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PTH and Calcitonin both regulate the reabsorption, uptake and use of Ca in what three major organ systems?
intestines, bones, Kidneys
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What re the action of Parathormone?
- Increased Ca uptake in the intestines
- in creased Osteoclast activity
- Increased Vit. D formation
- Increased Ca reabsorption in the kidneys
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What is Activated 1,25 (OH)2D3?
steroid hormone that causes GI cells to express genes to increase Ca uptake
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Teh end product of Activated 1,25 (OH)2D3 is to:
increase intestinal uptake of Ca
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When does bone growth cease?
Fusing of epiphyseal growth plates
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What are the major environmental factors effecting growth?
Disease and nutrition
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Irreversible stunting of growth can be caused by what?
malnutrition in utero
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IGF-1 is stimulated by what?
GH
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IGF-1 is primarily produced where?
The liver
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What are the effector sites for Ca homeostasis?
bone, Gi and kidneys
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What is measured to determine Ca homeostasis?
Ca plasma levels
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what two things regulate Ca absorptiona dn reabsorption?
PTH and Vit. D
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PTH and Vit. D regulate what?
Ca absorptiona dn reabsorption
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