Bone & Cartilage Flashcards
What is the CT that surrounds the outside of compact bone
Periosteum
What is the CT that lines inner surface of bone facing marrow cavity and haversian canals
endosteum
What are osteoblasts
secrete bone matrix (uncalcified); found only at the boundary bet bone and periosteum/endosteum
What are osteocytes
osteoblasts that have become “trapped” within lacunae of calcified matrix; connected to one another by gap jxns via processes that extend through canaliculi for the transport of nutrients and wastes.
what are osteoclasts
large, blood derived (related to macrophages) multinucleated cells that degrade the bone matrix (secretes H+ and lysosomal enzymes) for reabsorption.
What is bone matrix composed of
Organic: collagen (type 1) GAGs, glycoproteins
Inorganic salts: Calcium phosphate crystals
what are details of immature bone
layed down randomly; forms trabeculae that grow together.
Osteon=
concentric rings of lamellae. With lacunae
Bone is highly vascular:
blood vessels within marrow
blood vessels peripherate in marrow
blood vessels in matrix of bone.
What is the haversian canal
the vessels that run through the center of the osteon
what is volkmanns canal
interconnect the central canal and is a way to get blood vessels bet central canals
what are canaliculi
small canals; connect neighboring lacunae
immature bone has a randomly:
interwoven collagen fiber HAP matrix
Osteoblasts lay down new:
matrix in concentric lamellae
Cartilage is avascular CT T/F
T
What type of collagen in cartilage
Type II
Chondrocytes, unlike osteocytes:
Actively secrete matrix
where does chondroblast exist
between cartilage and CT; differentiate into chondrocytes as soon as they completely get surrounded by matrix.
What dont you see in cartilage
No vasculature!
what is the CT associated with cartilage
perichondrium; dense CT; contains fibroblasts and type I collagen. Has blood vessels but dont go into cartilage matrix.
Perichondrium is NOT present in:
articular surfaces and epiphyseal plates
what are chondroblasts derived from. They secrete matrix via ___ growth
progenitor cells in perichondrium; appositional
Chondrocytes secrete matrix via ____growth
interstitial; actively divide
What is hyaluronic acid composed of
a GAG; extremely long that has proteins, smaller GAGs attached via aggregan molecules