Bone tissue Flashcards
How can the structure of the bone be divided?
Cortical/compact bone (outside): only bone tissue.
Cancellous bone (inside): bone, medulla, blodd vessels, BONE MARROW.
What type of collagen is found in bone?
Type I collagen
Is bone tissue vascular o avascular?
Is highly Vascularized
Function of Osteonectin, Osteocalcin and Osteopontin
Osteonectin: anchors collagen.
Osteocalcin: calcium-binding.
Osteopontin: binding of osteoblast and osteocytes.
What’s periosteum?
Non-calcified connective tissue covering the external surface of the bone.
Whar attaches the periosteum to the bone surface?
Sharpey fibers (type I collagen)
Sharpey, la de high school musical
Which tissue supplies osteoprogenitor cells and osteoblasts to the bone, and for what?
Endosteum
Thin specialized connective tissue, that lines marrow cavities.
For bone growth and repair.
Which cells are the precursors of osteoblasts?
Osteoprogenitor cells
Which cells secrete the osteoid matrix?
Oscteoblasts
From where originate bone lining cells?
From osteoblasts that did not differenciate into osteocytes.
Which cells are in charge of remodeling and repair of damaged bone?
Osteoclasts
Of what type of cells is the endosteum formed?
One cell layer of osteoprogenitor cells (endosteal cells)
In what type of bone can we found osteons or Haversian systems?
Mature bone
What do osteosn have inside?
And surrounding?
A nerve, an artery and a vein.
Inside the Harversian canal.
Surrounding they have osteocytes found inside lacunae.
What are canaliculi?
Prolongations of osteocytes which are found between canaliculi.
Used to contact each otehr and exchange molecules for communication.
Differences between mature and inmature bone
Inmature bone: unmineralized, not concentric, +++ cells arranged randomly.
Mature bone: mineralized, concentric arrangement (osteons), less cells concentrically
From where do osteoclasts come?
From hemapoietic stem cells (bone marrow).
Form myeloid lineage (monocytes)
Release of growth factors (M-CSF, RANKL) by osteoblasts which induces osteoclastogenesis.
Function of osteoclasts
Bone degradation
Secrete acid, collagenases and proteases
Deminarilize bone matrix and degrade collagen type I
What inhibits osteoclastogenesis?
Osteoprotegerin
Receptor of RANKL (growth factor released by osteoblasts)
Morphology of osteoclasts
Giant multinucleated cell, highly polarized.
From what zone in osteoclasts do are enzymes released?
From the sealing zone.
How do osteoclasts increase the area of the membrane?
Through the ruffled border.
There are invaginations of the membrane,
What recruits osteoblasts?
The release of growth factors found in the bone by osteoclasts.
