part of part of has part has part has characteristic participates in develops from muscle cell cardiac muscle myoblast striated muscle cell cardiac muscle cell MESH:D032383 CALOHA:TS-0115 BTO:0001539 cardiac myocyte FMA:14067 cardiac muscle fiber cardiocyte Cardiac muscle cells are striated muscle cells that are responsible for heart contraction. In mammals, the contractile fiber resembles those of skeletal muscle but are only one third as large in diameter, are richer in sarcoplasm, and contain centrally located instead of peripheral nuclei. heart muscle cell cardiomyocyte This class encompasses the muscle cells responsible for heart* contraction in both vertebrates and arthropods. The ultrastucture of a wide range of arthropod heart cells has been examined including spiders, horseshoe crabs, crustaceans (see Sherman, 1973 and refs therein) and insects (see Lehmacher et al (2012) and refs therein). According to these refs, the cells participating in heart contraction in all cases are transversely striated. Insects hearts additionally contain ostial cells, also transversely striated muscle cells, but which do not participate in heart contraction. cardiocyte sarcomere heart contraction transversely striated primary circulatory organ