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