PHGY 214 Lecture Notes - Lecture 6: Epiphyseal Plate, Sex Steroid, Insulin-Like Growth Factor 1
9 Mar 2018
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Document Summary
Growth depends on gh but is influenced by other factors: genetic det of an individuals max growth capacity, as adequate diet, absence of chronic disease and stressful enviro conditions, normal levels of growth-influencing hromones. Insuling, thyroid, gonadal steroids increased bone growth by stim protein synthesis and cell divison does this in epiphyseal plate. Gh increase fat breakdown, has an anti-insulin affect. Pubertal growth onset is later in boys but longer in duration (3 vs 5 yrs: girls 11, boys 12-13 (last 5 yrs) Occurs at epiphyseal plate (made of chondrocytes which during puberty are proliferating and increasing in size, hypertrophy and hyperplasia) Osteoclasts clear out space, osteoblasts then deposit the ca there. When cartilage space is used up bone cannot grow any more canilculi fluid filled chans w lots of ca epiphyseal plate closure. Occurs when epiphyseal plate is fully ossified: hastened by presence of gonadal steroids, delayed when puberty is delayed.
