Seafood is a staple in nearly every Chilean's diet. Shellfish such as loco (abalone), erizo (sea urchin) and piure (an unusual red invertebrate) join more widely known fish, including sardines, salmon, congrio (conger eel) and atÃºn (yellowfin tuna).
To work efficiently, pipes need a way of regulating how much fluid can pass through them; they also need a way of switching the flow off completely. That's the job that valves do: valves are like mechanical switches that can turn pipes on and off or raise or lower the amount of fluid flowing through them.
How the Heart Valves Work. At the start of each heartbeat, blood returning from the body and lungs fills the atria (the heart's two upper chambers). The mitral and tricuspid valves are located at the bottom of these chambers. As the blood builds up in the atria, these valves open to allow blood to flow into the ventricles (the heart's two lower chambers). After a brief delay, as the ventricles begin to contract, the mitral and tricuspid valves shut tightly.