STEM CELLS Flashcards
What are totipotent cells
Totipotent cells are able to mature into any type of body cell
what are multipotent cells
Able to differentiate into a few different types of cell
eg both RBC and WBC can be formed from multipotent stem cells found in bone marrow
what are unipotent cells
these can only differentiate into one type of cell
eg there is a type of unipotent stem cell which can only divide to produce epidermal skin cells
how did specialised cells originate
from stem cells
where are totipotent stem cells found
only found in mammals in the first few cell divisions of an embryo
what stage do stem cells develop into after they have been totipotent
they then become pluripotent
what is a pluripotent cell
they are still able to specialise into any type of body cell but loose the ability to become the cells that make up the placenta
why do stem cells become specialised
they become specialised as different genes are expressed
During their development they only transcribe and translate part of their DNA
what are cardiomyocytes
heart muscle cells that make up a lot of the tissue in our hearts
can cardiomyocytes be replaced and if so with what
yes
with unipotent stem cells in the heart
give an example of stem cell therapy
Bone marrow stem contains stem cells that can become specialised to form any type of blood cell
Bone marrow transplants can used to replace the faulty bone marrow in patients that produce abnormal blood cells
Stem cells in the transported bone marrow divide and specialise to produce healthy blood cells
how could stem cells be used to treat spinal cord injuries
stem cells could be used to replace damaged nerve tissue
how could stem cells be used to treat heart disease
stem cells could be used to replace damaged heart tissue
how could stem cells be used to treat bladder conditions
stem cells could be used to to grow whole bladders which could then be implanted in patients to replace diseased ones
how could stem cells be used to treat respiratory diseases
donated windpipes can be stripped down to their simple collagen structure and then covered with tissues generated by stem cells, this can then be transplanted into patients
how could stem cells be used to treat organ transplants
organs could be grown from stem cells to provide new organs for people on donor waiting lists
what are the 3 sources of stem cells
Adult stem cells
Embryonic stem cells
iPS cells (induced pluripotent stem cells)
Advantages and disadvantages of adult stem cells
Easily obtained from body tissues of an adult
Eg found in bone marrow
Obtained via a simple operation
Little risk but lots of discomfort
Arent as flexible as embryonic stem cells
Can only specialise into a limited range of cells (as multipotent)
Advantages and disadvantages of embryonic stem cells
Obtained from embryos at early stage of development
Embryos are created in lab using vitro fertilisation (IVF)- egg cells are fertilised outside the womb
When embryo 4-5 days old stem cells are removed and then rest of embryo is destroyed
Can divide an unlimited number of times
Can develop into all types of body cells (as pluripotent)
How do iPS stem cells get created/ work
Created in the lab by reprogramming specialised adult body cells so they become pluripotent
Adult cells are made to express a series of transcription factors that are associate with pluripotent cells
Then adult stem cells express these pluripotent genes
Can be as flexible as the embryonic stem cell
iPS cells can be used in medicine
what is the ethical issue surrounding embryonic stem cells
-destruction of the embryo after stem cells have been obtained
