Morphometric Analysis of the Internal Ultrastructure of Mitochondria of Muscle Tissue of the Hair Gordionus alpestris (Nematomorpha)

A morphometric study of the internal ultrastructure of mitochondria of muscle tissue of the horsehair worm Gordionus alpestris (Nematomorpha) was carried out. As a main morphometric parameter measured, a generally accepted stereological parameter was taken, such as the surface area of the inner mitochondrial membrane per unit of the mitochondria volume, or the surface density of the inner membrane. The surface density of the inner membrane of the mitochondria of the Gordionus alpestris was compared with the respective parameters for mitochondria of the skeletal and cardiac muscle. It was found that the surface density of the inner membrane of the mitochondria of the horsehair worm corresponds to the values of this parameter for cardiomyocytes of mice at the age of 3 months and cardiomyocytes of Wistar rats at the age of 3 months and is even slightly higher than this parameter in mitochondria of the skeletal muscle of mice at the age of 3 months. The functional significance of a powerfully developed system of mitochondrial membranes of extended mitochondria of the horsehair worm is discussed as a structure necessary to ensure effective functioning of the contractile apparatus of the muscle tissue of the worm.