Insulin is produced by the green cells that are in clusters about the same size as the islets in the human pancreas. The red cells are producing another metabolic hormone, glucagon, that prevents low blood sugar.
Texas Gov. Rick Perry (left) listens to Tom Geisbert, a professor of microbiology and immunology at the University of Texas Medical Branch, explain the work researchers are conducting in a lab in the Galveston National Laboratory on Tuesday. Numerous Republicans, including Perry, have linked the first Ebola case diagnosed in the U.S. to border control and other political issues.