OCR A Level Biology:复习笔记2.6.11 The Use of Stem Cells

Stem Cells in Research & Medicine

Use of embryonic stem cells

  • Due to their ability to differentiate into multiple cell types, stem cells have huge potential in the therapeutic treatment of disease
  • For many countries, such as the USA and some countries within the EU, the use of embryonic stem cells is banned, even for research
  • In other countries, such as the UK, the use of embryonic stem cells is allowed for research but is very tightly regulated
  • Embryonic stem cells can be one of two potencies:
    • Totipotent if taken in the first 3-4 days after fertilisation
    • Pluripotent if taken on day 5

     

  • The embryos used for research are often the waste (fertilised) embryos from in vitro fertilisation treatment
    • This means these embryos have the potential to develop into human beings
    • This is why many people have ethical objections to using them in research or medicine

     

Use of multipotent adult stem cells

  • Adult stem cells can divide (by mitosis) an unlimited number of times but they are only able to produce a limited range of cell types
  • A small number of adult stem cells are found in certain tissues within the body such as:
    • Bone marrow - used to produce different types of blood cell
    • Brain - used to produce different types of neural and glial cells

     

  • These small numbers of stem cells remain to produce new cells for the essential processes of growth, cell replacement and tissue repair
  • Research is being carried out on stem cell therapy, which is the introduction of adult stem cells into damaged tissue to treat diseases (e.g. leukaemia) and injuries (e.g. skin burns)
  • The use of adult stem cells is less controversial than embryonic stem cells because the donor is able to give permission
    • For example, many people donate bone marrow to help treat leukaemia patients

     

  • However, if multipotent stem cells are being donated from one person to another they need to be a close match in terms of blood type and other body antigens
    • There is a chance that the cells used are rejected by the patient's immune system

     

  • Ideally, the patient's own adult stem cells are used to treat them, as there is a much lower chance of rejection

Table Showing the Uses of Stem Cells in the Treatment of Certain Conditions

 

Table evaluating the use of stem cells

 

 

 

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