Training. According to the American Physical Therapy Association, there were more than 200 accredited physical therapy programs in 2013. Master of Physical Therapy or Master of Science in Physical Therapy degrees are no longer offered in the U.S., and PTs in training now receive a Doctor of Physical Therapy degree.
Cell Membrane. The cell membrane (plasma membrane) is a thin semi-permeable membrane that surrounds the cytoplasm of a cell. Its function is to protect the integrity of the interior of the cell by allowing certain substances into the cell, while keeping other substances out.
Lipid Bilayer Structure. The lipid bilayer is a universal component of all cell membranes. Its role is critical because its structural components provide the barrier that marks the boundaries of a cell. The structure is called a lipid bilayer because it is composed of two layers of fat cells organized in two sheets. The lipid bilayer is typically about five nanometers thick and surrounds all cells providing the cell membrane structure.