Stem cells

STEM CELLS: THEIR DEFINITION,CLASSIFICATION AND SOURCES

Md. Najmul HossainBiotechnology & Genetic Engineering

University of Development AlternativeEmail: [email protected]

Stem Cells:Stem cells are unspecialized cells in the human body that are capable of becoming specialized cells, each with new specialized cell functions.

The best example of a stem cell is the bone marrow stem cell that is unspecialized and able to specialize into blood cells, such as white blood cells and red blood cells, and these new cell types have special functions, such as being able to produce antibodies, act as scavengers to combat infection and transport Gases .

Md. Najmul HossainBiotechnology & Genetic Engineering, UODA

Basic Characteristics of Stem Cells


Basic Characteristics of Stem CellsSelf assessment: Answer this

How do cells remain self‐renewing andunspecialized?


Classification and Sources of Stem Cells

Based on their origin: four broad types viz.

•stem cells from embryos;• stem cells from the fetus;• stem cells from the umbilical cord; and• stem cells from the adult.


Classification and Sources of Stem CellsBased on their potency:

• Some stem cells have more potential than others.POTENCY describes this flexibility.• Unipotent stem cells form only one type ofspecialized cell type.• Multipotent stem cells can form multiple types ofcells and tissue types.• Pluripotent stem cells can form most or all celltypes in the adult.• Totipotent stem cells can form all adult cell typesas well as the specialized tissues to supportdevelopment of the embryo (e.g., the placenta)


Sources of stem cells during development


Origin of Human Embryonic Stem Cells


Isolation of Human Embryonic Stem Cells

First done by Dr.James Thompsonand colleagues atthe University ofWisconsin (1998).


Comparision between ES & AS


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Stem cells

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