As I know, the effects of human activities on biogeochemical cycling are <span>examples of an ecological study involves the ecosystem level of organization.</span>
The heart has an intrinsic conduction system that causes electrical activity in the heart muscles causing them to contract. The intrinsic conduction system is made up specialized cells, that contain nerve and muscular characteristics.
The muscle cells in the heart are linked together by gap junctions, allowing cardiac action potentials to travel from one muscle cell to another.
Atrioventricular (AV) node. The damage to the AV node causes the electrical signals traveling from the upper chambers to the lower chambers to be impaired causing an AV block.
