Overview Rash from poison ivy. Many people develop an itchy rash that causes lines or streaks that look like this. Poison ivy, oak and sumac: Overview Many people get a rash from poison ivy, poison oak, and poison sumac. This rash is caused by an oil found in the plants. This oil is called urushiol (you-ROO-shee-all).
Cells in heart muscle process a lot of energy, so they have a large number of mitochondrion, the part of the cells where energy is made. Like all living things, cells die. The number of cells that an adult male loses per minute is roughly 96 million.
(modified/expanded from Wikipedia): The content of each phase is beautifully summarized in this outstanding Wikimedia Commons image by Kelvinsong : The fastest-dividing human cells can complete a cell cycle in about 24 hours (G1: 9h, S: 10h, G2: 4h, M: 30 min).