Reprinted from Bridges, 2001 Vol 12(1):5 ISSEEM

Though a human is comprised of over fifty trillion cells, there are no physiologic functions in our bodies that were not already pre-existing in the biology of the single, nucleated (eukaryotic) cell. Single-celled organisms, such as the amoeba or paramecium, possess the cytological equivalents of a digestive system, an excretory system, a respiratory system, a musculoskeletal system, an immune system, a reproductive system and a cardiovascular system, among others. In the humans, these physiologic functions are associated with the activity of specific organs. These same physiologic processes are carried out in cells by diminutive organ systems called organelles.

Cellular life is sustained by tightly regulating the functions of the cell’s physiologic systems. The expression of predictable behavioral repertoires implies the existence of a cellular "nervous system." This system reacts to environmental stimuli by eliciting appropriate behavioral responses. The organelle that coordinates the adjustments and reactions of a cell to its internal and external environments would represent the cytoplasmic equivalent of the "brain."

Since the breaking of the genetic code in the early 1950's, cell biologists have favored the concept of genetic determinism, the notion that genes "control" biology. Virtually all of the cell’s genes are contained within the cell’s largest organelle, the nucleus. Conventional opinion considers the nucleus to be the "command center" of the cell. As such, the nucleus would represent the cellular equivalent of the "brain." 

Genetic determinism infers that the expression and fate of an organism are primarily "predetermined" in its genetic code. The genetic basis of organismal expression is ingrained in the biological sciences as a consensual truth, a belief by which we frame our reference for health and disease. Hence the notion that susceptibility to certain illnesses or the expression of aberrant behavior is generally linked to genetic lineage and, on occasions, spontaneous mutations. By extension, it is also perceived by a majority of scientists that the human mind and consciousness are "encoded" in the molecules of the nervous system. This in turn promotes the concept that the emergence of consciousness reflects the "ghost in the machine."