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NAVL do Coração

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    Brian W.
    GB
    Brian W.

    The NAVL of the heart are the heart, nerves, arteries, veins and lymphatic's which influence the actions of the heart. Control of the hearts function is divided into three areas , The Extrinsic control( control from outside the heart), Intrinsic control(control from inside the heart), Humoral control, where some substances transported by the blood can accelerate or slow the action of the heart. A number of cardiac nerves arise from both the sympathetic portions of the nervous system. fibres from the sympathetic portion leave the central nervous system at the thoracic and lumber portions of the spinal cord, while those from the parasympathetic nervous system leave from the brain stem and the sacral region of the spinal cord. The sympathetic portion accelerates the action of the heart, while the parasympathetic portion slows it down. These portions are both controlled by the cardiovascular centres in the medulla of the hind- brainstem. In addition as we are all aware various emotional states can effect the actions of the heart. within the substances of the heart, certain fibres of the myocardium have been transformed from contracting muscle tissue to impulse-transmitting fibres. The sinoatrial (SA) node is a collection of impulse conducting fibres in the interatrial septum. The SA node is often called the pacemaker of the heart because it initiates each cycle of the contractions of the heart chambers. The atrioventricular (AV) node is a group of impulse conducting fibres just above the interventricular septum. Fibres descend from the AV node to form the bundle of his which branches into the right and left septal bundles. these branches pass down on either side of the interventricular septum. Impulses begin in the SA node, pass to the AV node, and then descend through the septal bundles and on to the purkinje fibres to stimulate the myocardium of the ventricular walls to contract.

    Brian W.
    GB
    Brian W.

    What are the septal bundles .

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