stem cells and their use in medicine

what is a stem cell?

A stem cell is a cell that can divide (by mitosis) an unlimited number of times

what has each cell got a potential of doing?

Each new cell (produced when a stem cell divides) has the potential to remain a stem cell or to develop into a specialised cell such as a blood cell or a muscle cell

what is this process called?

differentiation

what is potency?

This ability of stem cells to differentiate into more specialised cell types

what are the 2 types of potency?

1. totipotent

2. pluripotent

can totipotent stem cell differentiate into any type of cell found in an embryo?

yes

what other cells do totipotent cells create?

extra-embryonic cells

what are extra-embryonic cells?

the cells that make up the placenta and umbilical cord

what are pluripotent stem cells?

pluripotent stem cells are embryonic stem cells that can differentiate into any cell type found in an embryo

can they differentiate into extra embryonic cells?

no

other than embryonic stem cells, where can we find stem cells?

some adult tissues

Are they more or less potent than embryonic stem cells?

much less

what is multipotency?

multipotent stem cells are adult stem cells that have lost some of the potency associated with embryonic stem cells and are no longer pluripotent

explain everything you know about multipotent, pluripotent and totipotent stem cells:

why would using stem cells in medicine be a good idea?

As stem cells have the ability to differentiate into other specialised cell types, they are very valuable in medical research and treatments as they have the potential to replace damaged tissues and cells (that result from certain diseases)

what are the two sources of human stem cells?

• Embryonic stem cells

• Adult stem cells

what cells do embryonic stem cell differentiate into?

almost any cell type

what can they be used for?

embryonic stem cells have huge potential in the therapeutic treatment of many diseases

what are the 2 potencies that embryonic stem cells can be one of ?

• Totipotent if taken in the first 3-4 days after fertilisation

• Pluripotent if taken on day 5

what kind of embryos are used for research and where do they come from?

The embryos used for research are often the waste (fertilised) embryos from in vitro fertilisation (IVF) treatment

what did mean for the embryo?

• 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

can adult stem cells differentiate into any cell?

no only a limited rage of cell types

what are bone marrow stems cells used for?

used to produce different types of blood cell

what are brain stem cells used for?

used to produce different types of neural and glial cells

why can adult stem cells be a risk to se and quite unreliable?

if adult 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

• Otherwise, there is a chance that the cells used are rejected by the patient's immune system (the cells in the stem cell transplant are recognised as being foreign and are attacked 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

summary of stem cells

evaluating the use of stem cells: one weakness is… (ethics)?

The use of stem cells that are collected from embryos created via IVF is ethically questionable as this results in a viable embryo (an embryo that could become a foetus if implanted in a uterus) being destroyed

one weakness of using adult stem cells for medicine is ….(differentiation)?

adult stem cells is that, unlike embryonic stem cells, they are unable to differentiate into all of the specialised cell types (some of which may be required to treat certain diseases)

what does this mean for society?

This means that society has to use all the available scientific knowledge to make decisions about the use of stem cells (especially embryonic stem cells) in medical therapies, considering all the arguments for and against their use

a strength of using stem cells for medicine is….(treatment)?

it has potential to treat a wide-variety of diseases

table of evaluation of the use of stem cells in medicine: