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Monitoring Stem Cell Research 
Olfactory bulb: A part of the brain involved in detecting and dis- 
criminating among different smells. 
Oligodendrocyte; A type of neuroglia, that is, a particular type of cell 
that is part of the nervous system with supportive and metabolic 
functions rather than signal conduction, this type forms the myelin 
sheath around nerve fibers. 
Oocytes: Egg cells. 
Osteogenesis imperfecta: A large and miscellaneous group of condi- 
tions of abnormal fragility and plasticity of bone, with recurring frac- 
tures on trivial trauma. (SMD) 
Pancreas; An organ of the digestive system that secretes the hor- 
mones insulin and glucagon, as well as digestive enyzymes. 
Pancreatic beta cells: Cells of the pancreas (located in pancreatic 
islets, or islets of Langerhans) that produce insulin. 
Parkinson disease: A neurological syndrome usually resulting from 
deficiency of the neurotransmitter dopamine . . . ; characterized by 
rhythmical muscular tremors . . . (SMD) 
Phenotypic characteristics: The genetically and environmentally 
determined physical characteristics of an organism. 
Placenta: The oval or discoid spongy structure in the uterus from 
which the fetus derives it nourishment and oxygen. (NRC) 
Pluripotent: having great developmental plasticity, as a pluiipotent 
stem cell. Cells that can produce all the cell types of the developing 
body, such as the ICM cells of the blastocyst, are said to be pluripo- 
tent. 
Polarity: The property of having two opposite poles, sides or ends 
(for example, humans have left-right polarity, also front-back polarity 
and head-tailward polarity). 
Population doublings: The number of times cells growing in vitro 
have increased the total number of cells by a factor of 2 compared to 
the initial number of cells. 
PRE -PUBLICATION VERSION 
