Lecture 6: Tissue Renewel and Stem Cells Flashcards
(20 cards)
what type of maintenance do healthy tissues require
- cell division and cell death
what processes can initiate new cell growth
- stem cells
- differentiated cell division
what type of cell does not undergo cell renewal
photoreceptors in the eye for vision and auditory hair cells
Describe pulse chase experiments
these are experiments where you pulse something radioactive and chase it to see where it goes. this experiment is done to show that even non renewable cells undergo cellular turnover
True or false. Cell turnover can only be stem cell dependant
false.it can be both stem cell dependent and independent
describe the function and capabilities of stem cells
- they can divide indefinitely
- are not terminally differentiated
- can self renew (can remain stem cells)
- can differentiate
what are the 2 types of division stem cells undergo
asymmetric or symmetric
in symmetric division, how is it decided whether a stem cell remains a stem cell or it differentiates to become something else
environmental factors is the key factor in stem cell determination
in symmetric division, what does it mean for a stem cell to be flexible?
it means that both child cells can have the same fate if they are exposed to the same conditions
describe the role of stem cell niches in their ability to support self renewel
by mediating signals, it is able to kind of transduce or carry out signals to the stem cell to ensure that it remains a stem cell. if the stem cell leaves its niche it will differentiate
in asymmetric division how can stem cell fate be determined
by cell-cell contacts
after the cell differentiates, one cell will say in contact with the niche and remain a stem cell, while the other one will be pushed out of contact and differentiate
what is the benefit of stem cells dividing slowly
it reduces the chance for random mutations or telomere depletion
what does terminally differentiation refer to
the fact that a cell will not divide again as a result of being fully differentiated
how is the epidermis a good example of stem cell concepts
the basil lamina exemplifies the stem cell niche
the stem cells will divide symmetrically via the basil layer
transit amplifying cells divide rapidly and move t the prickle-cell layer
cells differentiate further
role of transit amplifying cells
to increase cell numbers before differentiation
describe the basics behind stem cell therapy
if you inject multipotent progenitor cells into a subject it can divide to become any type of cell given the environment it is exposed to. but once it becomes a commited progenitor, its fate has already been decided and wont converted into any type of cell
embryonic stem cells
you can get a culture of ES and they can divide into any type of cell
can genome expression be reprogrammed to change an adult cell back into a stem cell
yes through 4 transcription factors known as the oskm factors.
Induced pluripotent stems
these are cell that have been converted to stem cells from adult cells via OSKM factors
what type of stem cells are the majority of plant cells
totipotent (can produce any cell)
