Maningo,Mary Antonette D. CARDIAC MUSCLE TISSUE -Cardiac muscle fibers are striated,but they consist of individual cylindrical cells, each containing one (or two) central nuclei and linked by adherent and gap junctions at prominent interca- lated discs.Sarcomeres of cardiac muscle are organized and function similarly to those of skeletal muscle.During embryonic development mesenchymal cells around the primitive heart tube align into chainlike arrays. Rather than fusing into multinucleated cells/fibers as in developing skeletal muscle fibers, cardiac muscle cells form complex junctions between interdigitating processes.Cells within one fiber often branch and join with cells in adja- cent fibers. Consequently, the heart consists of tightly knit bundles of cells, interwoven in spiraling layers that provide for a characteristic wave of contraction that resembles wringing out of the heart ventricles.Contraction of cardiac muscle is intrinsic at nodes of impulse-gen- erating pacemaker muscle fibers; autonomic nerves regulate the rate of contraction. Reference:Junqueira’s Basic Histology Text And Atlas 14th Edition, Mescher pg.129