Neurons are electrically excitable cells that process and transmit information. They are the core components of peripheral nerves, the brain, of the spinal cord in vertebrates and the ventral nerve cord in invertebrates.
An antigen is a molecule that stimulates an immune response. When macrophages destroy pathogens they place antigens on their surfaces to stimulate the immune system. T-Cells then pick up the antigens and orchestrate the immune response.
Death Most Beautiful Programmed cell death ensures that our bodies contain just the right number of cells. This tightly regulated process removes damaged cells, shapes our organs and digits, and refines our immune systems. Here, multiphoton fluorescence imaging reveals an apoptotic HeLa cell (middle) amongst non-dying neighbors.