Answer:
Almost immediately after injection, you find yourself swept into a good-sized chamber, the left atrium. However, you do not stop in this chamber, but continue to plunge downward into a larger chamber below. You land with a large splash and examine your surroundings. All about you are huge white cords, hanging limply from two flaps of endothelial tissue far above you. You report that you are sitting in the left ventricle chamber of the heart, seeing the flaps of the mitral valve above you. The valve is open and its anchoring cords, the chordae tendineae, are lax. Since this valve is open, you conclude that the heart is in the systole/contraction phase of the cardiac cycle.
Explanation:
Once the oxygenated blood enters the heart through the pulmonary vein, it goes to the left atrium. From there, it goes down to the left ventricle passing through the mitral valve, also known as the bicuspid valve. This valve prevents blood's backflow when the heart contracts, allowing the blood's flow from the ventricle to the aorta.
The chordae tendineae, also known as tendinous cords, are in the mitral and the tricuspid valve. They are cords that are attached to the valve and the heart walls. They are lax during atrial systole, and with the help of blood pressure, they allow the valve to open and welcome the blood into the left ventricle. The tendinous cords are tense during ventricle systole preventing the valve from opening and causing a backflow from the ventricle to the atrium.
