Understanding:
• Structure of cardiac muscle cells allows propagation of stimuli through the heart wall
The heart is composed of cardiac muscle cells which have specialised features that relates to their function:
- Cardiac muscle cells contract without stimulation by the central nervous system (contraction is myogenic)
- Cardiac muscle cells are branched, allowing for faster signal propagation and contraction in three dimensions
- Cardiac muscles cells are not fused together, but are connected by gap junctions at intercalated discs
- Cardiac muscle cells have more mitochondria, as they are more reliant on aerobic respiration than skeletal muscle
These structural features contribute to the unique functional properties of the cardiac tissue:
- Cardiac muscle has a longer period of contraction and refraction, which is needed to maintain a viable heart beat
- The heart tissue does not become fatigued (unlike skeletal muscle), allowing for continuous, life long contractions
- The interconnected network of cells is separated between atria and ventricles, allowing them to contract separately
Structure of Cardiac Muscle Cells
