Physiology 3130Z Lecture Notes - Lecture 11: Apoptosis, Epiphyseal Plate, Melatonin
5 Oct 2017
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Document Summary
Endochondral: cartilage intermediate involved, axial & appendicular. Growth via limb buds with mesenchyme underneath. Condensations form cells come close together: cams (n-cadherins) hold cells together and send signals to chondrocytes, sox9 = master transcription factor of cartilage drives chondrogenesis, regulates aggrecan and collagen type ii. Chondrocytes produce ecm: aggrecan = large ecm proteoglycan, collagen type ii. Bone growth begins by: proliferation of chondrocytes, especially along the longitudinal axis, form columns of clone cells, hypertrophy of some chondrocytes (up to 10 times larger) No blood vessels present, therefore nutrients enter cell only from the outside. Oxygen is crucial hypertrophic cells are prone to hypoxia: molecular response to hypoxia: hypoxia-inducible factors, hif1-alpha = transcription factor, regulates vegf angiogenesis to hypertrophic region. Primary ossification centre = contains bone marrow. Growth plate in between proliferating and hypertrophic chondrocytes. Place bones in 24 well lanes, 1 bone in each well bones continue growing.
