BIO380H5 Lecture Notes - Lecture 16: Transforming Growth Factor Beta, Paraxial Mesoderm, Lateral Rectus Muscle
Document Summary
Bio 380 lecture 16 muscular system. The muscles are derived from the mesoderm. The skeletal muscles develop from the paraxial mesoderm; specifically, the somitomeres: the myotome. The splanchnic mesoderm is responsible for cardiac muscles and the smooth muscles for the gastrointestinal tract. The smooth muscles of the blood vessels are derived from local mesoderm. The lateral rectus muscle of the eye is the only muscles that originates from the somitomere. Extraocular muscles are derived from the prechordal plate. The muscle cells are derived from mesenchymal cells. The mesenchymal cells are restricted and called myoblasts. Once the myoblasts are determined, they enter the cell cycle via mitosis. As the myoblasts accumulate, they begin to differentiation via producing myogenic regulatory factors promote the synthesis of the protein p21: two myogenic regulatory factors switch on the p21 gene, the expression of p21 stops cell division. Once the myoblasts leave the cell cycle they are called postmitotic myoblast.
