Which one of the following is the structure of a cardiac muscle cell ?

Cardiac muscle cells, also known as cardiomyocytes, possess a distinct structural profile that differentiates them from skeletal and smooth muscle. They are characterized as cylindrical, branched, and typically uninucleate. Unlike skeletal muscle fibers, which are long, unbranched, and multinucleate, cardiac myocytes are shorter and form an interconnected network through branching. These cells usually contain a single, centrally located nucleus, although some may occasionally be binucleate [1]. A defining feature of cardiac muscle is the presence of intercalated discs, which connect the branched fibers to facilitate synchronized contraction [1]. While smooth muscle cells are spindle-shaped and uninucleate, they lack the striations and branching seen in cardiac tissue. Therefore, the combination of a cylindrical shape, branching architecture, and a single nucleus correctly identifies the structure of a cardiac muscle cell.

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1. [1] https://www.ncbi.nlm.nih.gov/books/NBK572070/