Figure 1.

Mitochondrial morphology and structure in cardiomyocytes. Mitochondria in cardiomyocytes can be categorized into three subtypes, subsarcolemmal mitochondria (SSMs) (in brown), interfibrillar mitochondria (IFMs) (in yellow), and perinuclear mitochondria (in orange), according to their distribution, size, and shape. The mitochondrial double-membrane consists of an outer mitochondrial membrane (OMM) (brown) and an inner mitochondrial membrane (IMM) (green and orange). The space between the OMM and the IMM is the IMS, and inside the IMM is the matrix. The IMM consists of the inner boundary membrane (orange) and cristae (green), the latter of which are formed by extensive inward folding of the IMM.