Bone Path Flashcards

Question

what is perosomus elumbus

Answer 1

agenesis of the lumbosacral spinal cord and vertebrae

Answer 2

improper segmentation of the somites in the embryo causing partial or complete fusion of adjacent vertebrae

Answer 3

includes the head, ribs, vertebrae and sternum

Answer 4

the bones of the thoracic and pelvic limbs

Answer 5

mesenchyme

Answer 6

intramembranous calcium is deposited around the extracellular matrix leading to the formation of trabeculae the initial fibrous membrane becomes periosteum and spaces between the trabeculae are filled with bone marrow

Answer 7

endochondrial ossification replacement of cartilage with bone osteoblasts form compact bone at the diaphysis the central cartilage cells enlarge and burst which when calcified become the marrow cavity

Answer 8

form osteoid for bone deposition plump, cuboidal, basophilic cells when active flattened and lining the bone surface when inactive

Answer 9

osteoblasts which have lost their ability to produce osteoid, they reside in the bone matrix in lacunae

Answer 10

responsible for bone resorption | are large, multinucleated cells with eosinophilic cytoplasm which sit on the bone surface with a ruffled brush border

Answer 11

lamellar (layered bone) which has 2 types: - spongy/ trabecular bone has large spaces filled with marrow, found in flat bones and at the epiphyses of long bones - compact bone has few spaces and is seen at the diaphysis of long bones over a layer of trabecular bone woven bone is newly formed bone with a disorganised arrangement and is yet to be organised into lamellar bone

Answer 12

the osteoclasts create an acidic environment on the bone surface hydrogen and bicarbonate are produced using water and carbon dioxide via carbonic anhydrase hydrogen ions are actively pumped out onto the surface of the bone, this acidity induces demineralisation

Answer 13

5-10 days, is more eosinophilic than mineralised osteoid

Answer 14

parathyroid hormone activates osteoclasts calcitonin inhibits osteoclasts vitamin D3 stimulates osteoclastic activity

Answer 15

- growth arrest lines - transverse calcified structures which lie parallel to the growth plate - Growth retardation lattice - persistence of non-properly formed areas of ossification at the growth plate and persistence of non-mineralised cartilage - woven bone seen at sight of fractures - resting lines - longitudinal, straight basophilic line - reversal lines - scalloped lines show edges of past osteoclast resorption

Answer 16

- endochodrial ossification occurs at growth plates where chondrocytes proliferate, enlarge and create a trabecular network which is then calcified. Osteoclasts and blasts then move in to remodel - intramembranous ossification occurs in condensed mesenchymal tissue