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 Your Heart Works. Each chamber has a sort of one-way valve at its exit that prevents blood from flowing backwards. When each chamber contracts, the valve at its exit opens. When it is finished contracting, the valve closes so that blood does not flow backwards.