EXAM 4 REVIEW: Bone and Hormones

long bone

upper and lower extremities

short bone

irregularly shaped bones in the ankle and wrist

flat bone

skull, rib cage, scapula

irregular bone

vertebrae and ethmoid bone

bone marrow

occupies the medullary cavities of the long bones throughout the skeleton

• also found in the cavities of cancellous bone in the vertebrae, ribs, sternum, and flat bones of pelvis

blood supply

• nutrient and perforating arteries supply blood to the cortical bones of long bones

• bone cells are nourished by diffusion from canaliculi

parathyroid hormone (PTH)

regulator of calcium and phosphate levels in the blood

• prevents drop in Ca levels

• prevents rises in P levels

PTH

increased Ca levels inhibit __ release

calcitonin

• inhibits release of calcium from the bone

• reduces renal tubular reabsorption of calcium and phosphate

• __ synthesis and release is stimulated by hypercalcemia

calcitonin clinical uses

• Paget disease

• hypercalcemia

vitamin D2

ergocalciferol

vitamin D3

cholecalciferol

vitamin D

• must be converted to be physiologically active and metabolized to compounds that mediate its activity

  • UV radiation from sunlight

  • intestinal absorption

• increases absorption of Ca, promotes actions of PTH on reabsorption. of Ca and P from bone, increases the amount of Ca and P available to the mineralizing surface of the bone