The Ultrastructure of the Cardiac Purkinje Strand in the Dog: A Morphometric Analysis

摘要: Purkinje strands from both ventricles of adult mongrel dogs were excised, and electrical properties studied by the voltage-clamp technique. The then examined with light electron microscopy structural analysed morphometric techniques. canine strand contains (by volume) about 28% myocyte 55% dense outer connective tissue. remainder volume is taken up inner shell loosely packed tissue within 10 μm a membrane. These fractions vary considerably one to another. Clefts less than wide occupy 18% clefts 1 1%. membrane surface area myocytes can be divided into three categories reference size adjacent cleft. About 47.8% faces wider μm, another 22.2% between 0.1 wide, final 30% wide. facing narrowest (less wide) nexuses 3%, desmosomes 10%, unspecialized 17% (each figure expressed as percentage total membrane). has more favourable anatomy sheep for most physiological experiments. We expect that complicating effects series resistance change in concentration extracellular ions will much smaller strands, but still not negligible.