HUBS 191 Lecture 4 Flashcards
what percentage of a bones ECM is organic
33%
what is the organic component of bones ECM composed of
collagen (a protein) that exists as a fibre which is suspended in a ground substance (proteoglycans)
Which component of a bones ECM is strong and has large amounts of tensile strength
Organic
what percent of the bones ECM is inorganic
67%
what is the inorganic component of a bones ECM composed of
hydroxyapatite and other Ca minerals (mineral salts)
which component of a bones ECM makes your bones hard and resistant to compression
the inorganic component
what are osteogenic cells
stem cells that produce osteoblasts
what are osteoblasts
cell builders that produce new bone matrix
what are osteocytes
cell maintainers that recycle proteins and minerals from the matrix. they also communicate with each other and other cell types
what are osteoclasts
cell destroyers that remove bone matrix we don’t need anymore
what are the holes that provide entrances for blood vessels called in compact bone
formamina
what are the circumferential rings around compact bone called
lamellae
what are osteons
longitudinal units within compact bone that are shaped like cylinders and provide a pathway for nutrients to get to the cells in the ECM
what is the central canal in compact bone
the space at the centre of the osteon which is filled with blood vessels and nerves
what are the rings around the central canal called
lamellae
what are the ‘lakes’ for the osteocytes called
lacunae
what are the channels that allow nutrients to travel to the osteocytes through the ECM called
canaliculi
what are interstitial lamellae
old osteons in the process of being broken down and remodelled
why aren’t blood vessels needed in cancellous bone (and therefore no central canal)
cancellous bone contains marrow which contains all the nutrients needed to feed to osteocytes
what are trabeculae
struts of lamella bone (rings), marrow sits between these rings
where are osteocytes located in cancellous bone
in lacunae between the lamellae/on the surface
how do we increase the width of a bone without making it too heavy
osteoblasts add lamellae to the outside of the bone and osteoclasts remove bone from the medullary cavity (middle of the bond usually filled with marrow)
why does bone need other be constantly destroyed (and remade)
bone is constantly being formed and destroyed in order to release minerals like calcium
what is it called when your OC activity outweighs your OB activity
osteoporosis
why do some people get osteoporosis
lack of oestrogen due to menopause, lack of exercise, age
