Musculoskeletal System Disorders Flashcards
What is bone matrix composed of?
Collagen fibers and calcium phosphate salts
Mature bone cells are called?
Osteocytes. They live in small passage called canaliculi that provide communication between the Haversian canals and the lacunae.
What type of cells differentiate into osteoblasts?
Osteoprogenitor cells.
What are osteoprogenitor cells derived from?
Embryonic mesenchymal cells
Osteoblast and osteoclast activity depend on which two hormones?
Calcitonin and parathyroid hormone
Which hormone stimulates osteoblasts?
Calcitonin
Which hormone stimulates osteoclasts?
Parathyroid hormone
What is the function of the parathyroid glands?
The parathyroid glands monitor the calcium in the blood 24 hours per day. The four parathyroid glands make more or less parathyroid hormone (PTH) in response to the level of calcium in the blood. When the calcium in our blood goes too low, the parathyroid glands make more PTH.
What does Calcitonin do?
Calcitonin is involved in helping to regulate levels of calcium and phosphate in the blood, opposing the action of parathyroid hormone.
What hormones does the thyroid gland secrete?
T3, T4, Calcitonin
What are the parts of a long bone?
The diaphysis - thin shaft, between two larger ends or epiphyses. The disphysis is formed of compact bone surrounding a medullary cavity containing marrow.
Metaphysis - area where the shaft broadens into the epiphysis.
Epiphysis - spongy bone covered by compact bone.
Hormones and factors that change density or thickness of bone
Growth hormone, parathyroid hormone, cortisol, stress (weight-bearing or muscle tension)
What is osteoporosis?
Loss of bone density due to loss of calcium salts
Periosteum
Except for the surface of bone covered by articular cartilage, the bone is covered by periosteum - a fibrous connective tissue. Contains osteoblasts, blood vessels, nerves and lymphatics, some of which penetrate into the canals in the bone.
What lines the medullary cavity?
Endosteum - contains osteoblasts.
