Quiz 2 Flashcards
Territorial Matrix
Newly formed matrix around a chondrocyte.
Stains intensely basophilic because high concentration of sulfated glycoproteins.
Howship’s Lacunae
Scooped out portions of the bone that are created by the action of an osteoclast
Interterritorial matrix
less-intensely staining matrix in between lacunae of cartilage
Isogenous Nest
A clone of cartilage cells from a single progenitor cells.
What gives the cartilage its basophilic color?
The presence of sulfated proteoglycan.
What is found in the extracellular matrix of hysline cartilage?
Some important: hyal
What is the fiber in bones?
Type 1 Collagen
What is Wolff’s Law?
Bone will remodel to resist forces placed on it.
Osteoblast function
Produce protein context of bone matrix (including fibers) called osteids. Secrete alkaline phosphates, which in the presence of calcium, phosphate and ATP will cause precipitation (mineralization).
Osteoclasts origin?
fusion of macrophage that come from circulating monocytes.
Where does intramembranous growth occur in an adult?
Occurs at the periosteum especially after a injury (callous)
What would you find in the extracellular matrix of hyaline cartilage?
Type II collagen fibers embedded in a ground substance comprised of sulfonated proteoglycans and glycosaminoglycans (GAGs). Some important constituents include: hyaluronic acid, chondroitin sulfate, keratan sulfate, chondroitin sulfate and heparan sulfate.
How does fibrocartilage differ from hyaline cartilage?
It contains a lot of type I cartilage, along with the type II. Therefore, it appears more eosinophilic.
Why do you have spongy bone?
Trabeculae of spongy bone add strength in a particular direction without adding much weight and allowing for a marrow space.
What would you find within canaliculi in the bone?
The processes of osteocytes would be in the canaliculi. They contact the cytoplasmic processes of adjacent osteocytes and have gap junctions whereby they pass nutrients back and forth.
What are the steps in intramembranous ossification?
Osteoblasts develop from mesenchymal osteoprogenitor cells. Cancellous bone (immature) is laid down. This bone undergoes compaction into cortical bone (immature) and remodeling then occurs with maturation of the bone.
What are the steps in endochrondral ossification?
A cartilage “model” forms from mesencymal tissue. This model gwows appositionally and interstitially. A bone collar forms at the middle of the shaft, cutting this area off from nourishment and resulting in dystrophic calcification f the cartilage model. Blood vessels invade through the bone collar. These bring other cells into the model. Osteoclasts break down the calcified cartilage, forming a marrow cavity. Osteoblasts lay down bone on calcified cartilage “spicules”. Secondary ossification centers forms at the epiphyses.
How does a bone increase in length?
The bone can only increase in length at the cartilage growth plate zones (epiphyseal plates). The growth in length of the bone is due to interstitial growth of cartilage (bone can not grow interstitially). There are zones of cartilage cells in the epiphyses. These include: a resting zone; a zone of proliferation; a zone of hypertrophy; a zone of calcification; and a zone of resorption. Osteoblasts will lay bone down on spicules of calcified cartilage and osteoclasts will break down calcified cartilage and the early bone in order to allow for production of mature bone.
Which parts of the sarcomere would get shorter during muscle contraction? Which would not?
The I band and the H zone would get shorter; the A band would not.
