DONE Cartilage And Bone Flashcards
Cartilage
Avascular, type of CT, all have chondrocytes surrounded by proteoglycan + hyaluronic acid (ground substance)
What are the 3 types of cartilage?
Hyaline, elastic, fibrocartilage
Chrondrocyte
Lies in a lacuna, lay down extracellular matrix as vesicles in cells, can’t undergo mitosis = damaged cartilage (replaced by scar tissue)
Hyaline cartilage
Type 2 Collagen Only cell = chondrocyte Precursor of bones for endochondral ossification @ articulating surface of long bones In tracheal wall
Elastic cartilage
Only cell = chrondrocyte
Has elastic fibres = flexibility + support
In 3 places only = pinna of ear, Eustachian tube, epiglottis
Fibrocartilage
Type 1 collagen
Cell type = chondrocytes + fibroblasts
Combo. of dense regular CT + hyaline cartilage
In areas of directional stress = intervertebral discs, knee meniscus
Resist shearing forces, shock absorber
Osteoprogenitor cells
Stem cell in inner layer of periosteum + endosteum
Osteoblast
Can’t divide, inner layer of endosteum + spicules, produce osteoid + lay down new bone = differentiate into osteocytes
Osteocytes
Differentiated osteoblast, trapped within osteon
Osteoclast
Large cells (50 nuclei) from fused monocytes in bone marrow, on endosteum of cortical bone, resorption of existing bone
Compact/cortical bone
Lamellae of compact, mineralised collagen = concentric
Trap osteoblasts
In shafts of long + flat bones = mechanical strength, protect organs
Spongy/cancellous/trabecular bone
Ends of long bones, centre of flat bones
Provide space for red marrow
Irregular trabeculae
Osteoarthritis
Age
Mechanical failure of articular cartilage
Narrowing of joint space
Rheumatoid arthritis
Autoimmune
Inflamed synovial membrane
Growth of bony spurs
Bone + articular cartilage both disintegrate
