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