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Bone Composition. Compact Bone. Spongy Bone. Medullary Cavity. Bone Composition. Articulating Cartilage located at both end of a long bone Allows smooth movement within joints while protecting the ends of the bones Periosteum
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Bone Composition Compact Bone Spongy Bone MedullaryCavity
Bone Composition Articulating Cartilage • located at both end of a long bone • Allows smooth movement within joints while protecting the ends of the bones Periosteum • Outer connective tissue that covers the entire length of the bone • Unites with tendons and ligaments at origin and insertion points Endosteum • Inner connective tissue lining the Medullary Cavity Medullary cavity • Inside diaphysis • Filled with red & yellow marrow • Red marrow is where blood cell formation occurs • Yellow marrow is composition of adipose cells and connective tissue
Bone Composition • Calcium carbonate and calcium phosphate: • Make up 60-70% of bone weight • Provide much of the bone’s stiffness and resistance to pressing or squeezing forces • Collagen: • Gives bone its characteristic flexibility and contributes to its ability to resist pulling and stretching forces • With aging, collagen is lost progressively and bone becomes more brittle. • Water • Bone consists of much smaller proportion of water than other body parts
Bone Classification • According to the degree of porosity, bone can be classified into two general categories: • Cortical or Compact bone (low porosity) • Spongy or Cancellous bone (high porosity)
Affect of Fitness on Bone • When bones are subjected to regular physical activity and habitual loads, they tend to become denser and more mineralized • e.g. Right forearm of a right-handed tennis player is more dense than their left forearm due to more frequent and consistent use. • Inactivity works in the opposite direction, leading to a decrease in weight and strength. • e.g. Loss of bone mass has been noted in bed-ridden patients, inactive senior citizens, and astronauts