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.
1 The definition of electricity is the flow of charge. 2  Usually our charges will be carried by free-flowing electrons. 3  Negatively-charged electrons are loosely held to atoms of conductive materials. 4  With a little push we can free electrons from atoms and get them to flow in a generally uniform direction.he atomâs electrons arenât all forever bound to the atom. The electrons on the outer orbit of the atom are called valence electrons. With enough outside force, a valence electron can escape orbit of the atom and become free. Free electrons allow us to move charge, which is what electricity is all about.