15. Stem cells

Human bodies are made up of \(200\) specialised cell types, each of which can perform a specific function.

 

Stem cells, in contrast to differentiated cells, are a mass of undifferentiated or unspecialised cells with variable potency. The following are two important properties of stem cells that set them apart from other cells:

 

a. It can divide and give rise to more stem cells through self-renewal.

 

b. It can give rise to specialised cells with specific functions through the process of differentiation.

 

i. Embryonic stem cells (ESC):

 

They are derived from the inner cell mass of the blastocyst. ESCs can be extracted and cultured from early embryos. Embryonic stem cells can differentiate into any cell in the body.

 

  

ii. Somatic stem cells or adult stem cells:

 

They are found in both neonatal (newborn) and adults. Somatic stem cells can divide and give rise to specific cell types. They can be found in amniotic fluid, the umbilical cord, and bone marrow.

 

Sometimes the cells, tissues and organs in the body might be permanently damaged or lost due to genetic conditions, injury or disease. In such situations, stem cells are utilised for the treatment of diseases. The procedure is known as stem-cell therapy. Neuronal stem cells can be utilised to replace the damaged or lost neurons in patients with neurodegenerative disorders, including Parkinson's disease and Alzheimer's disease.