stem cells Flashcards
what is a stem cell called because it can diffrentiate into almost any type of cell
pluripotent
what is a stem cell called because it can diffrentiate into any type of cell
totipotent
what is a stem cell called when it can divide into multiple but not all cell types
multipotent
what do stem cells have ability to do
self renew (reproduce themselves many times over)
when is an embryo totipotent
-first cell formed when sperm fertilizes egg (zygote)
-and after the first few cell divisions (blastomeres)
when is an embryo pluripotent
-when it developed into a blastocyst (ball of cells formed from blastomeres)
why is a blastocyst pluripotent
because:
-the inner cell mass can become nearly any but not all cells (cant become placenta and umbilica)
parts of a blastocyst
sources of embryonic stem cells
-embryonic stem cells (early embyro when zygote begins divisions)
-stem cells in umbilical cord blood (multipotent)
-adult stem cells found in developed tissues like bone marrow
-induced pluripotent stem cells
how do induced pluripotent cells form
-reprogramming diffrentiated cells to become undiffrentiated when they respecialise
-to switch on certain genes and become undiffrentiated
how are stem cells used in bone marrow transplant
-treat disease of the blood (lukemia) and immune system
-restore blood system after treatment for specific types of cancer (bone marrow cells obtained, stored, then put back)
uses of stem cells in drug research
-stem cells develop into human tissue
-new drugs can be tested on this rather than animal cells
how to get embryonic stem cells
(1) after IVF, donation of unused embryos for stem cell research
(2) through embryonic cloning
what is embryonic cloning
-nucleus removed from egg cell
-nucleus inserted into egg cell
-electrically stimulated
-develops into embryo
stem cell research in developmental biology
-can understand how multicellular organisms develop
-make particular cell types to see how they function and what goes wrong when diseased
uses of embryo to repair damaged tissue and replace lost tissue
-treat mice with type 1 diabetes by programming stem cells to become pancreatic beta cells
-bone marrow cells to treat liver disease
-directed to become nerve tisue to treat alhzhimers or repair spinal cord injuries
difficulties of stem cells
-need to find out which cytokine cell signalling molecule needed to direct the differentiation of stem cells into particular type of cells
-difficult to culture in a lab
use of stem cells for organs (regenerative medicine)
-can populate a bioscaffold of an organ then directed to develop and grow into specific organs for transplanting
-patients cells are obtained, reprogrammed into iPS cells, then used to make organs
-no need for immunosuppressant drugs
what are adult stem cells
-can become specialised to repair and replace surrounding differentiated cells
-multi-potent
example of adult stem cells
hematopoietic
-stem cell found in bone marrow which can differentiate into various blood cells (red, lymphocytes, platelets)
how to grow stem cells
-remove from blastocyst and culture in petridish
-stem cells divide several times and scientists divide the population into other dishes
-after several months, there are millions of stem cells
-stem cell line occurs potentially
-cell lines can be frozen and shared between labs for developing therapies
whats a cell line
-if stem cells continue to grow without differentiating
