AN ESTIMATE OF CAPILLARY ANISOTROPY AND DETERMINATION OF SURFACE AND VOLUME DENSITIES OF CAPILLARIES IN SKELETAL MUSCLES OF THE CONGER EEL (CONGER CONGER L.)

Abstract

Fast and slow muscle fibers were isolated from the axial muscles of conger eel (C. conger) and examined by EM. Volume densities of mitochondria, Vv (mit, f); intracellular lipid stores, Vv (lip, f); and myofibrils, Vv (mf, f) were, respectively, 0.23, 0.18, 0.47 for slow and 0.03, 0.002, 0.79 for fast fibers. Factors affecting the representative sampling of capillary supply were investigated using semithin (0.5 .mu.m) sections. An estimate of the degree of capillary anisotropy was made using the assumption of a Fisher axial distribution (Mathieu, Cruz-Orive, Hoppeler et Weibel, 1983). The capillary bed is highly anisotropic. Mean capillary cross-sectional area, determined from EM, was 25.7 and 30.5 .mu.m2 for slow and fast muscle, respectively. The number of capillaries per unit cross-sectional fiber area, NA (c, f); volume Vv (c, f); and surface density, Sv (c, f) of capillaries was 615 mm-1 0.016, 135 cm-1 for slow and 21.3 mm-1 0.0007, 4.7 cm-1 for fast muscle, respectively. The relationship between the extent of the capillary bed and mitochondrial volume density is discussed in relation to the function of different muscle types.