part of has part bearer of participates in develops from muscle cell cardiac muscle myoblast striated muscle cell cardiac muscle cell BTO:0001539 CALOHA:TS-0115 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. FMA:14067 FMA:83808 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. cardiac muscle fiber cardiac myocyte cardiocyte cardiomyocyte cell heart muscle cell cardiocyte sarcomere heart contraction transversely striated primary circulatory organ