You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Phase of cardiac action potential, where calcium channels close & slow potassium channels open : and explain in detail?
In cardiac action potential Phase O - Rapid upstroke - due to fast sodium channels- Influx of Na+Phase I - Initial repolarization - fast Na channels - closePhase II - Plateau - due to calcium influx Phase III - Rapid repolarization - Calcium channels close & slow potassium channels open Phase IV - Resting membrane potential - - 90 mv