Animated heart beating[Cut to inside view of the heart, showing four chambers]Narrator: Your heart has four chambers: two atria on top and two ventricles below.[Show blood flow entering the right atrium]Narrator: Blood low in oxygen flows into the right atrium from the body.[Show blood moving to the right ventricle and then to the lungs]Narrator: It’s then pumped into the right ventricle and sent to the lungs to pick up oxygen.[Show oxygen-rich blood returning to the left atrium]Narrator: Now, oxygen-rich blood returns to the left atrium.[Show blood moving to the left ventricle and then to the body]Narrator: From there, it moves into the left ventricle, which pumps it out to the entire body.[Show heart valves opening and closing]Narrator: Valves in your heart ensure the blood flows in the right direction.[Cut to animated person exercising, heart beating faster]Narrator: When you exercise, your heart beats faster to supply your muscles with more oxygen.[Closing shot: Animated heart beating with a heartbeat sound effect]Narrator: And that’s how your heart keeps you going strong, every single day![End screen with channel logo and subscribe button]