KINESIOL 3U03 Lecture Notes - Lecture 2: Myocyte, Myogenesis, Myosatellite Cell
19 Sep 2016
School
Department
Course
Professor
Document Summary
Skeletal muscle: impacted by pa and performance and influenced by these factors, goes through growth, maturation and development, fetal muscle. Separated by extracellular material: at birth (term) Larger diameter fibres/tightly packed: changes in composition (chemical too) With growth: concentration of extracellular ions (na and ci) decrease, concentration of intracellular components (k and p) increase. Extracellular component decreases: increase in fibre number (prenatal, increase in fibre size (post natal) Total muscle nitrogen increases (non protein and cellular: prenatal to adulthood. Fibrillar protein % increases postnatally: physical demand (activity/contraction, anabolic hormones. Extracellular protein % increases to max at birth: declines postnatally to adulthood, parallel: increase in fibre number prenatal. Satellite cells: pluripotent (mesodermal) cells, mitosis/single nucleus/no fusion or contractile. Myoblasts no mitosis/single nucleus: capable of fusion/contractile protein. Myoblasts fuse with myotubes: multinucleated cells, may contain sarcomere, no motor innervation. Mature muscle: mature multinucleated cells, myofibrils, motor innervation. Satellite cells incorporated into mature muscle fibre injury may stimulate myogenesis.
