STEM CELLS: Flashcards
Stem cells are ________
undifferentiated (unspecialised)
Why does Stem Cell activity have to be controlled?
They need to divide fast enough to efficiently replace tissues and prevent aging. However, the divisions must be limited to prevent the growth fo tumours.
A stem cell’s ability to differentiate into different cell types is called:
potency
Totipotent
can differentiate into any type of cell. The first 8 or 16 divisions of the zygote are of totipotent cells. Can differentiate into extra-embryonic tissues e.g amnion
Pluripotent
can differentiate into all tissue types but not entire organisms. Present in early embryos in the blastocyst.
Multipotent
can only form a range of cells in a specific tissue. E.g Haematopoetic stem cells in bone marrow.
Sources of animal stem cells?
Tissue stem cells and embryonic stem cells
Embryonic Stem Cells
Very early stages totipotent but become pluripotent after the formation of the blastocyst.
Tissue (adult) stem cells)
Multipotent, but some evidence suggests they can be triggered into becoming pluripotent. Can be extracted from a newborn’s umbilical cord, due to plentiful supply.
Sources of plant stem cells
Meristematic tissue found at sites of growth. Meristem tissue is also found between the phloem and xylem in a vascular cambium. Plant stem cells remain pluripotent.
What diseases could stem cells treat?
Heart disease (Repair muscle tissue)
Type 1 diabetes (replace insulin-producing cells)
Parkinson’s disease (repair brain tissue)
Alzheimer’s disease (~~~~~~)
Macular degeneration (Repairing eye and nervous tissue)
Birth defects (reverse birth defects)
Spinal Injuries (restore nervous tissue)
What are the 3 areas Stem Cells are being used?
Treating burns
drug trials
developmental biology
Ethical issues of stem cells
removal of stem cells from embryos destroys embryos
religious and moral objection
“embryo rights”
