stem cells

• Stem cells 


  unspecialised cells - they can develop into different types of cell.
• where are stem cells found 


  in early embryos and bone marrow
• differentiation 


  The process by which a cell becomes specialised for its job
• Stem cells are also able to divide to produce more undifferentiated stem cells, i.e. they can renew themselves.
• Bones are living organs, containing nerves and blood vessels. The main bones of the body have marrow in the centres. Here, adult stem cells divide and differentiate to replace worn out blood cells - erythroctes (red blood cells) and neutrophils (white blood cells that help to fight infection).
• differentiation of stem cells in bone marrow

  A) neutrophil

  B) erythrocyte

  
• Plants are always growing, so stem cells are needed to make new shoots and roots throughout their lives. Stem cells in plants can differentiate into various plant tissues.
• In plants, stem cells are found in the meristems (parts of the plant where growth can take place). In the root and stem, stem cells of the vascular cambium divide and differentiate to become xylem vessels and phloem sieve tubes.
• Heart disease is a big problem in many countries. If it results in heart tissue becoming damaged, the body is unable to sufficiently replace the damaged cells. Researchers are currently trying to develop ways of using stem cells to make replacement heart cells to repair the damaged tissue.
• With Alzheimer's, nerve cells in the brain die in increasing numbers.

  This results in severe memory loss. Researchers are hoping to use stem cells to regrow healthy nerve cells in people with Alzheimer's.
• Patients with Parkinson's suffer from tremors that they can't control.

  The disease causes the loss of a particular type of nerve cell found in the brain. These cells release a chemical called dopamine, which is needed to control movement. Transplanted stem cells may help to regenerate the dopamine-producing cells.
• Stem cells are also used by scientists researching developmental biology, i.e. how organisms grow and develop. Studying stem cells can help us to understand more about things like developmental disorders and cancer.