skeletal system Flashcards
What are the basic functions of the skeletal system?
- Protection of vital organs
- Storage of chemical energy in yellow bone marrow
- Haemopoiesis in red bone marrow
- Storage of minerals (calcium and phosphorus)
- Attachment point for skeletal muscles
- Provides a structural framework
What are the two divisions of the skeletal system?
- Axial Skeleton (80 bones)
- Appendicular Skeleton (126 bones)
What does the diaphysis refer to in a long bone?
The shaft or body of a long bone
What is the role of articular cartilage?
Covers the ends of bones at joints, reducing friction and absorbing shock
What is the periosteum?
The outer covering of bone that contains bone cells for growth in thickness
What are the two types of bone tissue?
- Spongy Bone (Trabecular)
- Compact Bone (Cortical)
Describe spongy bone.
Characterised by small needle-like pieces called trabeculae; forms the core of epiphyses in long bones
What are the organic components of the bone matrix?
- Collagen proteins (~90%)
- Other proteins (osteocalcin, osteonectin)
- Growth factors (IGF, IL-6)
What are osteogenic cells?
Bone stem cells that are the only bone cells capable of dividing
What is the function of osteoblasts?
Build new bone tissue and initiate calcification
What do osteocytes do?
Mature bone cells that assist with daily metabolic activities of the bone
What is the role of osteoclasts?
Remove or resorb bone tissue by digesting the extracellular matrix
What is bone modeling?
The formation of new bone, such as during childhood growth
What is bone remodeling?
A continuous cycle of bone resorption and formation
What are the stages of the bone remodeling process?
- Resting
- Activation
- Resorption (by osteoclasts)
- Reversal
- Formation (by osteoblasts)
Which minerals are crucial for bone creation?
- Calcium
- Phosphorus
- Magnesium (aids calcium absorption)
What vitamins support bone health?
- Vitamin A (supports osteoblast activity)
- Vitamin C (essential for collagen synthesis)
- Vitamin D (promotes calcium absorption)
- Vitamin B12 (involved in synthesis of bone proteins)
What is Dual-energy X-ray Absorptiometry (DXA)?
A method for measuring bone mineral density (BMD) in a 2D format
What is Wolff’s Law?
States that bone will optimise its structure to withstand the functional loading placed upon it
What does the Mechanostat Theory propose?
A localised response of bone to loading
What is osteoporosis?
A systemic skeletal disease characterised by a lack of bone mineral mass
How is osteoporosis diagnosed?
Based on BMD values measured by DXA, expressed as standard deviations (SD) from a reference mean
Who is at risk for osteoporosis?
- Elderly men and women
- Middle-aged women (post-menopause)
- Athletes
- People with eating disorders
- Sedentary individuals
- Astronauts
What are stress fractures?
Bone conditions caused by excessive repetitive loading
