Bone Flashcards
How many bones at birth and adulthood?
270 and 206
Functions of bone
weight bearing/support Protection Blood formation Mineral store Movement
Compact bone
Outside layer giving bone white solid appearance
How is compact bone arranged?
Osteons/ haversian systems - concentric rings and osteocytes
Medullary cavity
Stores red bone marrow
Endosteum
Membrane inside
Periosteum
Membrane outside the bone
Spongy bone
Lamellated trabeculae filled with bone marrow and orientation reflects forces
Endochondral development
Long bones
Cartilage model and blood vessels invade
cartilage => bone In epiphyseal growth plate which eventually ossifies
Intramembranous
Flat bones and clavicle
Mesenchymal cells=>osteoprogenitor cells=> osteoblasts
Residues turn to blood vessel and bone marrow
Osteoblasts
Cells with a single nucleus that synthesise bone
Osteocytes
Star shaped bone cell found in mature bone
Found in lacunae and canalicuni
Osteoclasts
Breaks down bone tissue - derived from Mo
Hydroxyapaite crystals
Concrete and support
Collagen
Reinforced steel as flexible and strong under pressure
Osteoporosis
Degrade bone faster than made
Paget’s disease
Excessive breakdown and formation of bone - pain and deafness as nerve compressed
Osteopetrosis
Bones harden and become denser as less resorption by osteoclasts
What happens to women’s bones after menopause?
Bone mass decrease due to less calcium
Oestrogen declines so more ostoclasts
What has a negative effect on bone mass?
Weightlessness and bed rest
What has a positive impact on bone mass?
High impact sport
Homology
The similarity in arrangement, position and function of structures in creatures that are derived from a common ancestor
