Ventral Root of Spinal Nerve. The ventral root (motor root) of each spinal nerve consists of axons from motor neurons whose cell bodies are found within the gray matter of the spinal cord. A ventral root and a dorsal root unite to form a spinal nerve, which passes outward from the vertebral canal through an intravertebral foramen (bone opening). A posterior branch (posterior ramus) of each spinal nerve turns toward the posterior to innervate muscles and skin of the back.
Studies to date suggest that the planktonic-biofilm transition is a complex and highly regulated process. The results reviewed in this article indicate that the formation of biofilms serves as a new model system for the study of microbial development.tudies to date suggest that the planktonic-biofilm transition is a complex and highly regulated process. The results reviewed in this article indicate that the formation of biofilms serves as a new model system for the study of microbial development.
1 The Lac operon is an interesting example of how gene expression can be regulated. 2  Viruses, despite having only a few genes, possess mechanisms to regulate their gene expression, typically into an early and late phase, using collinear systems regulated by anti-terminators (lambda phage) or splicing modulators (HIV). Down-regulation occurs, for example, when a cell is overstimulated by a neurotransmitter, hormone, or drug for a prolonged period of time, and the expression of the receptor protein is decreased in order to protect the cell (see also tachyphylaxis).