Flashcards in Bone Histology (Lect) Deck (77)
What are the two types of bone developement?
What kind of bone usually developes intramembranously?
flat bones (e.g skull bones)
What happens if blood vessels are near mesenchyme?
they enlarge and will become bone rather than cartilage
How do mesenchymal cells condense yet remain attached to each other?
they maintain their gap junctions
What do mesenchymal cells first differentiate into on their way to becoming bone?
What do osteoprogenitor cells differentiate into?
What is osteoid?
a non-mineralized matrix laid down by osteoblasts that later mineralizes into a bone spicule (aka canaliculi)
What happens when osteoblasts become trapped and can no longer divide?
they become osteocytes
Does osteoid stain dark?
What is deposited that causes bone calcification?
What is formed by bone spicules growing together?
What is absolutely essential for bones to live?
What is the osteogenic layer?
The outer layer of osteoblasts that line up on the outside and inside during intramembranous bone formation to lay down compact bone
What are the two layers of periosteum?
The fibrous layer and the osteogenic layer
What type of cell is formed by the fusion of monocytes from bone marrow?
What hormone accelerates the activity of osteoclasts?
parathyroid hormone (happens when Ca2+ and PO4 are low)
What hormone slows the activity of osteoclasts?
T or F: osteoclasts are mononucleated?
Describe the location and activity of osteoblasts and osteoclasts in the widening of bone?
osteoblast must be working to build bone on the exterior
osteoclasts must work to clean away bone on the interior
Increase in bone width is an example of?
T or F: all bones have both spongy and compact bone
True - all bones have this component, it doesn't matter how it formed
What is the point of having weaker spongy bone in the interior of bones?
it helps reduce bone weight
When the growth plate recedes what is formed?
What happens to red marrow as you age?
some of the red marrow may be converted to yellow marrow
How many cells thick is the endosteum?
1 layer thick
How is bone decalcification performed for preparation methods?
acid is used to extract the mineral
What is the consistency of bone that has been decalcified?
tough and rubery, and can be cut like any other tissue
What is the ground method of bone prep?
bone is cut with a diamond saw and ground until its thin enough to see through, no stains are used
What do dark areas in ground bone represent?