Flashcards in Musculoskeletal System Deck (68)
The outer layer of bone is called___________. It makes up __% of the bone mass and is very______and _________
Makes up 80%
Very dense and compact
The inner layer of bone is called ___________ or _________ bone. It is less _______ and _________ than the outer layer
Cancellous or trabecular
Stiff and Strong
Joints are composed of 3 parts.......
Intramembranous Ossification is a model of __________. It occurs when.......
It occurs when mesenchymal cells differentiate into osteoblasts which form bone
Endochondral Ossification is a model of __________. It occurs when
It occurs when a cartilage model, created by chondrocytes, is converted to bone by mineral deposition
What is bone remodeling?
The process by which old bone is resorped and new bone is layed down
What are osteoclasts?
Osteoclasts are multi-nucleated cells that resorp bone
They connect to bone via the protein integrin
When attached they become polarised
What are osetoblasts?
Active bone forming cells that produce a collagenous bone matrix
What is osetoporosis?
A systemic skeletal disease characterized by low bone mass and micro-architectural deterioration of bone tissue. This causes an increased susceptibility to fracture
What are the risk factors for osteoporosis
Low Ca intake/absorption
Alcohol and Drug use
Low body weight
What are the 2 major pathogenic processes for osteoporosis?
Poor bone mass acquisition in adolescence
Accelerated bone loss during the 6th decade
What causes poor bone mass acquisition?
Hormone deficiencies and malnutrition along with decreased physical activity
What causes accelerated bone loss?
Increased activity of osteoclasts without the same increase in osteoblast activity. Bone is being broken down faster than it is being formed
What chemicals increase Bone formation?
Vitamin D metabolites
What chemicals decrease Bone formation?
What chemicals increase Bone resorption?
High doses of Vitamin D metabolites
What chemicals decrease Bone resorption?
What is BDM?
Bone Density Measurement, the lab test for determining if a patient has osteoporosis. Low BDM and many remodeling markers indicate higher incidence of fractures
What are some initial tests for osteoporosis?
Blood cell count
Ca and PO4 levels
Kidney and Liver Function tests
TSH, Oestrogen and Testerone levels
What are some additional tests undertaken to screen for osteoporosis?
Screening for Hyperparathyroidism
24 hour urine test to rule our hypo/hypercalciuria
Serum Protein electrophoresis to rule out multiple myeloma
What is a urinary marker to show bone resorption has occurred?
Collagen cross-link fragments found in urine
What is DEXA and what does it stand for?
The most popular BDM test, Dual-Energy X-ray absorptiometry
Even though CT scans are more sensitive they aren't used as much to screen for osteoporosis because........
They expose the patient to more radiation
What is a T-score?
The result given by DEXA, it is the number of standard deviations above or below the the mean BDM for a given race/gender
What factors influence who should be treated for osteoporosis ?
Family history of osteoporosis
Risk factors for boneless (hyperparathyroidism, immobilisation etc)
Lots of bone remodeling markers
Should you treat a women with osteoporosis and no fractures?
Should you treat a women with osteoporosis and fractures
Should you treat a women with osteopenia and a fracture?
Should you treat a women with osteopenia and no fractures?
No, however, follow up check should be done in 1-3 years