Valves of the Heart. The heart functions by pumping blood both to the lungs and to the systems of the body. To prevent blood from flowing backwards or âregurgitatingâ back into the heart, a system of one-way valves are present in the heart.
An electric circuit is a path in which electrons from a voltage or current source flow. Electric current flows in a closed path called an electric circuit. The point where those electrons enter an electrical circuit is called the source of electrons.
Introduction. Electricity travels easily through electrical conductors, like metals. Materials that do not let electricity pass through them easily are called electrical insulators. Plastic, wood, glass and rubber are good electrical insulators.ntroduction. Electricity travels easily through electrical conductors, like metals. Materials that do not let electricity pass through them easily are called electrical insulators. Plastic, wood, glass and rubber are good electrical insulators.