The properties of cardiac muscle are always changing as a result of sympathetic and parasympathetic nervous stimulation and pharmacological drugs that alter or stimulate molecular mechanisms in the heart. In order to understand the mechanisms of the heart, we must experiment with the heart by observing the properties of cardiac cells and formulate hypotheses for their observed response.
The structure of cardiac muscle consists of myocardial cells which have a nucleus, contractile filaments (striations), several mitochondria and intercalated discs which contain gap junctions (Silverthorn, 2007). Surrounding the myocardial cells are t-tubules whereby electrical ions can flow into the cell membrane proteins and start action potentials (Silverthorn, 2007).…