Thursday, March 25, 2010

Definition Of Cell Differentiation

Cell differentiation is the final phase in a process of cell development--cell specialization. The initial stage, the totipotent stage--in which the cell could develop into any human body cell (blood, brain, liver)--eventually moves to the differentiation stage, in which the cell moves toward specialization (a designated type of cell with a specific purpose in the body).


Stage 1: Single-cell Zygote


Biologically, humans start life as a single-cell zygote---a single-celled fertilized egg (also known as a totipotent cell)--during reproduction. Totipotent cells in the fertilized egg produce more totipotent cells, with each one having the potential ability to become any type of human cell needed by the forming embryo: a liver cell, a brain cell or other cell within the body.


Stage 2: Cell Determination


After four days of the embryonic totipotent cell duplication phase, the cell determination phase begins---and is heavily influenced by gene factors. Cells begin to lean toward a specialized purpose within the developing body. Some of them do remain totipotent cells (like stem cells), but the majority of the other cells now start to develop specific cellular shapes and characteristics that will aid them in performing the activity or function they will be tasked with doing for the body.


Stage 3: Cell Differentiation


The process of cells becoming specialized is known as cell differentiation. After the cell moves from the totipotent stage--in which it could be used in any part of the growing body--and moves into the determination stage, where heredity and genes influence and determine its future use in the body, it must develop into the specialized cell it will become. This is known as cell differentiation.


Differentiation Influences


Just as heredity and genes influenced cell development and determination in Stage 2, the cell differentiation stage is also influenced by external stimuli. This influence by factors like growth motivates the changing cell to begin producing the components necessary for the part of the body it will serve.


For example, one cell may become a red blood cell during the specialization process, thus requiring it to be able to produce hemoglobin to aid in the transport of oxygen throughout the blood in the body.


Differentiation and Specialization


Once differentiation processes are complete, the cell is now recognized as a specialized cell, unique in structure and chemical makeup from different types of other specialized cells within the body (brain cell shape and chemical makeup differ from that of blood cells).


Over 200 cells exist in the developed human body, and while most are specialized cells, some types of remaining undifferentiated totipotent cells (such as the stem cells) have the potential to produce differentiated cells, while also maintaining their ability to perform as a totipotent cell. And according to the Ohio State University, the differentiated cells produced by undifferentiated cells (stem cells) can be used to replace cells in many diverse body functions (like the immune system or neurons in the nervous system).







Tags: body Stage, stem cells, totipotent cell, body Stage Cell, brain cell, cell differentiation