Describe the role of nodal tissue in the cardiac cycle.

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Please find below the answer:

Heart is a nodal tissue that contracts and generates nerve impulses that travel throughout the heart wall. It has two nodes-SA node and AV node. They play an important role in the conduction of nerve impulses. 

The stimulus for contraction of the heart originates in a specific region of the right atrium called the sino-atrial node (SAN). Once contraction has begun it spreads through the walls of the atria through the network of cardiac muscle fibres. The atrial muscle fibres are completely separated from those of the ventricles by a layer of connective tissue, except for a region in the right atrium called the atrioventricular node (AVN). The structure of AVN is similar to that of SAN and is connected to a bundle of specialized muscle fibres, which provides the only route for the wave of excitation from the atria to the ventricles.

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