Cardiac Muscle Histology

Cardiac muscle is striated, uninucleate, involuntary muscle.

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In this low power view, (mag: 11,550 in the original image), sarcomeres (S) can be seen, starting at one Z line and ending at the next (marked by arrow heads).Note the alignment of the Z lines along adjacent myofibrils. Collagen microfibrils (small arrows) can be seen in the extracellular space. Note the capillary, with red blood cell (RBC). A cell-cell junction, the intercalated disc (ID), is visible. M, mitochondria; N, nucleus. Click within the image for closeups.

This view of the myofibrils shows their lack of uniformity, and the density of mitochondria:

Closeup of intercalated disc, showing tight junction (FA) and desmosome (D):

Portion of intercalated disc showing gap junction (GJ) and desmosome (D):