Purkinje fibers or Purkinje cardiomyocytes are part of the whole complex of the cardiac conduction system, which is today classified as specific heart muscle tissue responsible for the generation of the heart impulses. From the point of view of their distribution, structure and ultrastructural composition of the cardiac conduction system in the ostrich heart were studied by light and electron microscopy. These cells were distributed in cardiac conducting system including SA node, AV node, His bundle and branches as well as endocardium, pericardium, myocardium around the coronary arteries, moderator bands, white fibrous sheet in right atrium, and left septal attachment of AV valve. The great part of the Purkinje fiber is composed of clear, structure less sarcoplasm, and the myofibrils tend to be confined to a thin ring around the periphery of the cells. They have one or more large nuclei centrally located within the fiber. Ultrastructurally, they are easily distinguished. The main distinction feature is the lack of electron density and having a light appearance, due to the absence of organized myofibrils. P-cells usually have two nuclei with a mass of short, delicate microfilaments scattered randomly in the cytoplasm; they contain short sarcomeres and myofibrillar insertion plaque. They do not have T-tubules. 1. Introduction Jan Evangelista Purkinje was born on 18 December, 1787, in Libochovice (Bohemia). Between the ages of 35 and 63, he made his most significant discoveries. This very age generally displays the physiological measure of the biggest creative waves of the human being. From 1850 until his death in 1869, Purkinje worked in the Institute of Physiology in Prague, which he had based. The acquisition of the big Pl？sl microscope in 1835 represented an important turning point for Purkinje’s histological and embryological research. Purkinje published his discovery of a part of the heart conduction system, nowadays called Purkinje fibers or Purkinje cardiomyocytes [1]. Tawara (1906) was able to follow proximally from the Purkinje fibers (P-fiber) to the besides bundles, which, he organize, were connected to his bundle. Afterwards, he found that his bundle was connected proximally to a well-set plexus of fibers (which he called a node, in his book). This is the arterioventricular node. In addition, he was able to display interdigitating connections between the Purkinje fibers and ventricular muscles, as well as between the node and arterial muscles [2]. Electrical activity of the specialized conducting system of canine hearts has been recorded in
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