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 Plateau phase of ventricular muscle is due to opening of: and explain in detail?
Phase 2 (plateau), calcium channels open and fast potassium channels close.
A brief initial repolarization occurs and the action potential then plateaus as a result of:
(1)  Increased calcium ion permeability.
(2) Decreased potassium ion permeability. The voltage-gated calcium ion channels open slowly during phases 1 and 0, and calcium enters the cell. Potassium channels then close, and the combination of decreased potassium ion efflux and increased calcium ion influx causes the action potential to plateau.
Key Concept:
Ca++and K+ channels remain open during plateau phase (phase 2) of AP. But Ca2+ initiates the plateau phase, as K+ channels are already open from phase 1. This Ca++ channel in phase 2 is also known as calcium-sodium channel.