Skeletal System: Function and Components of Bone Flashcards
What are 5 functions of the SKELETAL system?
1) Movement e.g. MUSCLES pull on BONES
2) Protection e.g. ribcage protects heart and lungs
3) Support e.g. VERTEBRAE, PELVIS (reproductive organs)
4) Mineral storage e.g. calcium
5) Blood cell formation e.g. in BONE MARROW
What % of BONE is made up of HYDROXYAPATITE CRYSTALS?
65%
What % of BONE is made up of OSTEOID?
33%
What % of BONE is made up of cells?
2%
What is the S & F of HYDROXYAPATITE CRYSTALS?
S - Made of calcium salts
F - Make up majority of BONE, crystals alone are hard but brittle
What is the S & F of OSTEOID?
S - Protein-carbohydrate complexes and collagen fibers
F - Collagen alone is flexible but can’t support weight
What is the F of CELLS?
F - Build and remove BONE MATRIX
CRYSTALS formed around COLLAGEN are…
…a hard, flexible substance that is harder than steel for its weight
What is the F of OSTEOGENIC CELLS?
They divide to form OSTEOBLASTS
What is the F of OSTEOBLASTS?
They build BONE MATRIX
What is the F of OSTEOCLASTS?
They remove BONE MATRIX
What is the F of OSTEOCYTES?
They maintain BONE MATRIX (found in LACUNAE)
Which population of CELLS is busiest in young people (<30 years)?
OSTEOBLASTS
Which population of CELLS takes over as people age?
OSTEOCLASTS (can result in OSTEOPOROSIS)
When astronauts are in space, what type of CELLS increase in number and what does this result in?
Increase in OSTEOCLASTS = less BONE MASS
