Overo refers to several genetically unrelated pinto coloration patterns of white-over-dark body markings in horses, and is a term used by the American Paint Horse Association to classify a set of pinto patterns that are not Tobiano.
Cerebrospinal fluid signals control the behavior of stem cells in the brain. FULL STORY. When stem cells from the old brain are cultured with signals of a young choroid plexus they can divide and form new neurons (red).
The Structure of the Cell Membrane. The cell membrane (or plasma membrane) surrounds all living cells, and is the cell's most important organelle. It controls how substances can move in and out of the cell and is responsible for many other properties of the cell as well.