Bone Intro Flashcards
bone is what type of tissue?
connective tissue
bone is composed by what types of connective tissue?
organic and inorganic
what is the inorganic component of bone?
what is the purpose for this component?
hydroxyapatite - gives bone strength by storing Ca, P, Na, and Mg
what will hydroxyapatite form in bone?
osteoid which is type 1 collagen
how is osteoid formed?
deposition of calcium hydroxyapatite
what are the cells of the bone?
Osteoprogenitor cells
Osteoblasts
Osteocytes
Osteoclasts
what are osteoprogenitor cells?
cells that make osteoblasts and are pluripotent mesenchymal stem cells
bone formation occurs in what type of environment?
alkaline
osteoblast are responsible of making what?
osteoid
osteoblasts contain high amounts of what?
alkaline phosphatase
osteoblast modify the activity of what other bone cell?
osteoclasts
osteoblasts have receptors for what?
PTH, Vit. D, and estrogen
what can you assess if you find a lab report that shows elevated alkaline phosphatase?
when do you see alkaline phosphatase?
this is a marker for bone formation
bone diseases that have increased bone turnover
what are osteocytes?
osteoblasts that get surrounded by matrix
how do osteocytes communicate with each other?
using canaliculi or tunnels
what is the function of osteocytes?
they regulate Ca levels and remodel the skeleton
how do osteoclasts look in the microscope?
multinucleated giant cell
osteoclasts are derived from the the same cell as what other cells?
monocytes and macrophages
osteoclasts contain a high amount of what?
acid phosphatase and collagenase
where do osteoclasts do resorption of bone?
within Howship’s lacunae
what factors influence osteogenesis by acting on osteoblasts and stromal cells?
what will these factors stimulate?
IL-1** (also, IL-6, 3, 11)
M-CSF**
change the activity of: RANK, RANK-L, Osteoprotegerin
where do you find RANK?
on precursors of osteoclasts
where do you find RANK-L?
on osteoblasts
binding of RANK to RANK-L will cause what?
development of osteoclasts
who secretes osteoprotegerin?
osteoblasts
osteoprotegerin acts as what?
a decoy receptor
what does osteoprotegerin do?
binds to RANK-L and blocks its action (STOPS oscteoCLASTogenesis)
what do parathyroid and prostaglandins do?
increase RANK-L, decrease Osteoprotegerin, increase bone resorption
what does estrogen do to bone?
lessens M-CSF and stimulates osteopretegerin, so it stops osteoclastogenesis
what are the proteins found in bone?
type 1 collagen made by osteoblasts
what are the 2 types of bone?
Lamellar and woven
when do you see woven bone?
fetal skeleton
how fast is woven bone made?
fast
what kind of force does woven bone resist?
all types of forces from all directions equally
what is lamellar bone?
orderly layered collagen deposition
how strong is lamellar bone?
more strong than woven
what is Intramembranous bone?
bone formation without a “cartilage model”
what part of the body are made of intramembranous bone?
Flat bones such as the cranial bones, clavicles, vertebrae, ankle bones.
what is Endochondral bone?
Indirect bone formation from a cartilage model, formed from cartilage at the epiphyseal growth plates
what types of bones are made of endochondral bone?
long bones (femur or humerus)
