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Histology
Bone
37
Histology
Professional
09/29/2011

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Cards

Term
What are the types of bone cells(4)?
Definition
osteoprogenitor, osteoblast, osteocyte, and osteoclast
Term
Which bone cell is not found on the bone surface?
Definition
osteocyte
Term
What is the function of osteoblasts?
Definition
synthesize organic components: osteoid tissue (collagen fibers and ground substance), and secrete alkaline phosphatase (calcium deposition)
Term
What enzyme is secreted by osteoblasts?
Definition
alkaline phosphatase; deposition of calcium salts
Term
What is the function of osteocytes?
Definition
maintain bone matrix
Term
Which bone cells have gap junctions?
Definition
osteocytes
Term
What are the enzymes secreted by osteoclasts and the action of each?
Definition
carbonic anhydrase - decalcification of bone matrix; collagenase - break down collagen fibers
Term
Which hormone stimulates osteoclastic activity?
Definition
parathyroid hormone
Term
What do you know about Howship's lacuna?
Definition
A depression active sites (divet into the surface of the bone)
Term
What bone cell has a ruffled border?
Definition
Osteroclasts
Term
What is the major organic component of bone matrix?
Definition
collagen fibers
Term
What are the main minerals of the bone matrix?
Definition
calcium phosphate and calcium carbonate
Term
What are the two forms of calcium phosphate?
Definition
hydroxyapitite crystals and calcium phosphate salts
Term
What do you know about Sharpey's fibers?
Definition
collagen fibers that connect periosteum to outer circumferential lammellae of compact bone
Term
What is the function of the periosteum?
Definition
outer surface of the bone; outer layer (dense irregular CT) blood vessels; inner layer (loose areolar CT) osteogenic cells
Term
What is the function of the endosteum?
Definition
osteogenic cells (make osteoblast, which make bone)
Term
Which bone is stronger: woven or lamellar?
Definition
lamellar
Term
What are 2 types of lamellar bone and its location?
Definition
Compact bone - shafts of long bones; spongey bone - flat and irregular bones
Term
What is the unit structure of compact bone?
Definition
trabeculum
Term
Which canal is parallel to the long axis of bone?
Definition
Haversian canals
Term
What is the function of Volkmann's canals?
Definition
communication between blood vessels
Term
What is the function of bony canaliculi around osteocyte processes?
Definition
transmit interstitial fluid and nutrients
Term
What covers the surface of trabeculae of spongy bone?
Definition
endostium
Term
Define intramembranous ossification
Definition
bone growth within a vascularized embryonic connective tissue (mesenchyme)
Term
What are some bones that ossify through intramembranous ossification?
Definition
flat bones of the skull
Term
Which zone contains degenerating cartilage cells?
Definition
Calcifying zone
Term
Which cells lay down bone in the ossification zone?
Definition
osteoblasts
Term
What is the effect of estrogen on bone?
Definition
decreased osteoclast and increase osteoblast
Term
What is the effect of parathyroid hormone on bone?
Definition
stimulates osteoclasts and increases blood Ca++
Term
What is the effect of thyrocalcitonin on bone?
Definition
lowers blood calcium level
Term
What is the effect of growth hormone on bone?
Definition
Pituitary; excess - giantism, or acromegaly; decrease dwarfism
Term
What is the effect of vitamin D deficiency on bone?
Definition
leads to defective absorption of Ca++ from the intestine and leads to rickets in children and osteomalacia in adults (soft but strong bones)
Term
What is the effect of vitamin C deficiency on bone?
Definition
defective collagen formation; scurvy (bones are rigid but weak)
Term
How does bone grow in width?
Definition
appositional growth by the osteoblasts
Term
How does bone grow in length?
Definition
activity of hyaline cartilage of epiphyseal plate
Term
Can bone brow by the interstitial method like cartilage?
Definition
no
Term
What is the main mineral in bone matrix?
Definition
Calcium hydroxyapatite
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