Fabric cardionector
The fabric cardionector or nodal fabric is a fabric encrusted in the Cœur, at the origin of the automatic contraction of the Myocarde.
The cardiac automatism is the property which presents the heart of
to contract rythmiquement in the absence of any stimulation which could reach him
others organes.
When it is separated from the remainder of the organization, the heart of a mammal can
to continue its activity during hours, if one perfuse his coronary system
with blood incoagulable, or quite simply with a nutritive liquid approprié.
Morphological data
Quantitatively not very abundant, the nodal fabric is consisted cells
muscular showing several characteristics of fabric myocardic
embryonic; these cells are drowned in the myocardic mass of fabric and
the nodal fabric name owing to the fact that they are divided into cluster or nœuds.
carries
The distribution of this nodal fabric inside the myocardium is unequal: these
cells are gathered to form two nodes (connected by a network
internodal) and a filament ramifié.
The nodes are both located, in the mammal, in the wall of
the right auricle.
- the first called node of KEITH and sinusal FLACK or is presented in the form of a small white trail located on the surface part of the wall of the Atrium right, between the meeting of both venas cava, near the higher vena cava. It is in this vicinity of the large venous trunks that it owes its name of sinusal node, by analogy with the heart of batrachian where venous blood flows in a sine:
- the second, node of atrio-ventricular ASCHOFF-TAWARA or , is on the level of the postéro-lower portion of the partition inter-atrial, in the right atrium, in front of the meeting of the coronary sine.
- These two nodes would be connected by three ways of conduction ( former, median and posterior ) which are nodal fabric bands mingled with myocardic fibers. The former way divides after having circumvented the higher vena cava in a beam going down towards the atrio-ventricular node and a beam towards the left atrium (beam of Bachmann). The existence and the real role of preferential conduction of these ways still make the subject of debate.
- the node of ASCHOFF-TAWARA is prolonged by a filament of approximately 2 cm, the beam of HIS , which goes down along the partition inter atrial crosses the right atrio-ventricular partition, then engages in the fibrous portion of the septum interventriculaire and is divided into two branches.
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