What happens during depolarization in cardiac cells?

During depolarization in cardiac cells, there is a significant shift in the electrical state of the cell membrane. This process is primarily characterized by the influx of positively charged ions, particularly sodium (Na+) and in some cases calcium (Ca2+), into the cells. As these positively charged ions enter, they cause the inside of the cell to become more positive relative to the outside, leading to a change from a resting potential to an active potential. This change is crucial for the initiation and propagation of electrical signals in the heart, which ultimately coordinate muscle contractions.

Understanding this process is vital because depolarization triggers the contraction of cardiac muscle cells, leading to heartbeats and consequently the overall function of the heart. It's an essential mechanism that ensures the heart pumps efficiently, making the comprehension of ion movements during depolarization fundamental for those studying EKGs and cardiac physiology.