Mitochondria

Somewhere I read that mitochondria are the powerhouse of the cells, but I don’t know what that means. What do they actually do?

Mitochondria provide you with energy, including the energy you needed to ask the question. They are tiny energy factories inside most cells that generate most of the cell's supply of chemical energy that is stored as adenosine triphosphate (ATP). The energy produced powers everything you do. In the brain, vast amounts of energy is needed to transmit information across the synapse or the space between neurons, to power functions that allow you to learn, think, feel, remember, and maintain cognition in the aging process. Brain cells utilize three times as much oxygen as body muscle cells and twice the energy of any other type of body cells. The brain grabs 20 percent of all the energy that is generated, even though it accounts for only about 2 percent of the total body weight. Bottom line: Without the mitochondria, the powerhouse of the cells, you would soon be history.