Homeostatic Imbalances/ Calcitonin and Parathyroid hormone negative feedback loop
Pituitary dwarfism
GH deficiency in children resulting in extremely short long bones and maximum stature of 4 feet.
Osteomyelitis
Inflammation of bone and bone marrow caused by pus-forming bacteria Fatal before antibiotics
Acromegaly
adulthood hype secretion of GH causes overgrowth of bony areas still responsive to GH such as bones of face
Osteoporosis
bone resorption occurs at a faster rate than bone deposition Often seen in post menopausal women
Paget's disease
characterized by excessive bone formation and breakdown Usually in spine
Gigantism
childhood hyper secretion of growth by the pituitary gland causes excessive growth
Parathyroid hormone negative feedback loop
1. PTH hormone is released by cells of parathyroid gland in response to lower blood Ca+ levels 2. PTH binds to osteoblasts causing them to release osteoblasts stimulating factor, raises osteoblast activity which raises breakdown of bone matrix and raises Ca+ into blood 3. PTH raises calcitrol synthesis which raises Ca+ absorption 4. PTH lowers urinary Ca+ excretion and raises urinary phosphorus excretion
Calcitonin hormone negative feedback loop
1. Raises blood 2. calcitonin is released by C cells of thyroid gland in response to raising blood Ca+ levels 3. stimulates osteoblast activity so excess Ca+ is taken from blood and deposited as matrix
Osteomalacia
Bones are inadequately mineralized causing softened, weakened bones Main symptom is pain when weight is put on it
Rickets
Bones of children are inadequately mineralized causing softened, weakened bones Bowed legs and deformities of the pelvis