skeletal system Flashcards
functions of bone/skeletal system
support, protect, assist in movement, mineral homeostasis, blood cell production, triglyceride storage
which minerals are bones a reservoir of?
calcium and phosphate
where specifically does blood cell production take place?
red bone marrow –> hemapoiesis
describe the medullary cavity in children vs adults
in kids, it has red bone marrow; in adults it has yellow bone marrow
Describe metaphysis
it is where the diaphysis meets the epiphysis
It contains the epiphyseal line/plate
Periosteum
- membrane that covers the outside of the bone
- outer layer = fibrous layer = dense irregular ct
- inner layer = osteogenic layer = osteoprogenitor cells (also osteoblasts + clasts)
- has perforating fibers
- super well supplied with nerves and blood vessels
endosteum
areolar connective tissue that covers the trabeculae
recipe for bone cell matrix
25% water
25% collagen fibers
50% crystalized mineral salts (mostly CaPO3)
describe the extracellular matrix of bones
- osteoid = organic part = collagen, proteoglycans (trap water), and glycoproteins
- mineral salts = inorganic = calcium phosphate and calcium carbonate
describe the calcification process
- initiated by osteoblasts
- mineral salts are layed down and crystalize on framework formed by collagen fibers
4 types of bone cells
- osteogenic = stem cells which undergo cell division to make cells that become osteoblasts
- osteoblasts = bone building cells that lay down collagen
- osteocytes = mature bone cells –> maintain bone tissue and exchange nutrients/waste with blood –> boxed in osteoblasts
- osteoclasts = release enzymes that digest the mineral component of bone matrix –> regulate blood calcium levels
what is the structural unit for compact bone? for spongy bone?
osteon and trabeculae
canaliculi
tiny canals that connect lacunae –> provide routes for nutrient and oxygen to reach osteocytes
what connects the central canals in osteons?
what are the layers of osteons called?
- perforating canals
- lamellae
3 types of lamellae
- concentric
- interstitial
- circumferential
where are trabeclui lined?
they orient themselves along stress lines