Vitamin D
Absorption of calcium in the intestine. Activated by ultraviolet radiation
Vitamin A
Needed for bone resorption that occurs during normal development. Retarded development of bone occurs without it.
Vitamin C
needed for synthesis of collagen which is used by osteoblasts to make osteoid.
Pituitary Gland
Human Growth Hormone
Stimulates reproduction of cartilage cells in epiphyseal plates
Thyroid Hormone
Thyroid Gland -T3 and T4 stimulates the replacement of cartilage in epiphyseal plates. Excessive secretion halts bone growth. A deficiency causes stunted growth.
Calcitonin
calcium storage in bone
Sex hormones
Androgens (testosterone), and Estrogens . Testes, ovaries and adrenal gland (zona reticularis of adrenal cortex).
Parathyroid Gland
parathormone. Stimulates osteoclasts to release calcium into the blood stream.
Minerals
Calcium 25% Phosphorus 12% Magnesium 0.37% Potassium 0.7% Zinc .009% Copper .0009%
Protein
for Osteoid production
Etiology:
Vitamin C deficiency leading to inadequate production of collagen
S/S
Internal bleeding into joints, periosteum and mucus membranes, petechiae, ecchymoses, anemia, pallor, bleeding gums and loose teeth.
Tx
Restore vitamin C intake. 100-200 mg p.o. daily
Etiology:
Rate of bone resorption increases while rate of bone formation slows down causing loss of bone mass.
Lack of estrogens and androgens in post-menopausal women
and androgens in post-menopausal women
Nutritional disorders
not enough protein or calcium in diet
Disuse
Lack of exercise which is necessary for osteoid formation. “Atrophy”of disuse.
Example: patient’s whose extremities have been in a cast for six weeks.
Osteoporosis Treatment
Basically symptomatic and try to prevent additional fractures Estrogens to decrease bone resorption Fluoride to stimulate bone formation Calcium and Vitamin D Teach patient good body mechanics
Symptoms of Osteomalacia - Rickets
Etiology:
Sunlight stimulates ergosterol
Renal Rickets
Etiology
Vitamin D deficiency either due to inadequate dietary intake, malabsorption in gastrointestinal tract or too little sunlight.
Sunlight stimulates ergosterol in the skin and makes vitamin D active.
Vitamin D is necessary for the absorption of calcium and phosphorus in the GI tract.
Renal Rickets
kidney injury causes retention of phosphorus in the body which stimulates the parathyroid gland to release parathormone and increase calcium levels in the blood by removing calcium from the bone.
Osteomalacia
There is plenty of osteoid but no calcium to provide strength. Bow legs, knock knees result
Hyperparathyroidism - Primary
is where one or more of the parathyroid glands enlarge and increase the secretion of PTH (parathormone). Parathyroid adenoma accounts for 80% of this problem