The image given is cardiac muscle, as it is showing Intercalated discs which is typical for cardiac muscle & Perinuclear halo is seen. It is striated muscle (not as striated as skeletal muscle) Usually in a cell, the following cell junctions are seen in a sequence Surface of cell Tight junctions (most superficial) - Absent in cardiac muscle Zona adherens (20nm) Desmosomes/Macula adherens (25mm) - holds 2 cells together Gap Junctions - imp in cardiac muscle Gap Junctions are narrow gaps usually working as electrical synapses, they let pass ca+2 ions & maintain quick transfer of cardiac impulses & maintain rhythmic contractions If gap junctions are compromised, Problem occurs in electrical synapses which leads to arrhythmia. Tight junctions (Zona occludens) are absents in cardiac muscle. Hemi-desmosomes attach cell to basement membrane. Given structure is not skeletal muscle because skeletal muscle is more striated & there is no peri-nuclear halo in it. It is not smooth muscle because smooth muscle is spindle shaped and is not striated.