Definition is a rhetorical mode that can be used in something smaller or shorter than a full paper. You can use extended definition for several paragraphs only in a paper of much greater length. You also can add to a paper a one-paragraph definition--like a brief encyclopedia definition.
Depending upon location, neural crest cells give rise to most of the peripheral nervous system, as well as various non-neural tissues, like craniofacial bone and cartilage, the thymus and parathyroid glands, and the cardiac outflow tract â in short, all of the tissues that are affected in DiGeorge syndrome.
The molecular basis for the causation of congenital rubella syndrome are not yet completely clear, but in vitro studies with cell lines showed that rubella virus has an apoptotic effect on certain cell types. There is evidence for a p53-dependent mechanism.