Cellular differentiation and Stem Cells Flashcards
At what point do we consider an embryo as a foetus?
Before 8 weeks = embryo
after 8 weeks = foetus
What develops from the trophectoderm?
the placenta and other support systems
what develops from the inner cell mass?
The organs and other important things
Describe cell division, cell differentiation, and morphogenesis
cell division = growth of cell population where one cell grows and divides to produce two daughter cells
cell differentiation = cell becomes specialised to carry out a specific function
Morphogenesis= control orientation and spatial distribution of cells
How do cells differentiate?
They express different genes - based on the signalling from their environment
Why are stem cells different from any other cell in the body?
Stem cells are different b/c they can self renew to maintain the stem cell pool AND they can differentiate and become something entirely different.
Why is a Stem Cell Niche important?
the niche (or microenvironment) around the stem cell provides the support and signalling regulating self renewal and differentiation
Where can we get stem cells from?
1) embryonic stem cells= blastocysts (very early embryo)
2) tissue stem cells = from foetus, baby, or adult - often from the umbilical cord
3) induced pluripotent stem cells from a laboratory
Define the terms
multipotent
Pluripotent
and Totipotent as they relate to stem cells
Multipotent = can make multiple types of specialised cells but not all types i.e.) blood stem cells can only make types of blood cells
Pluripotent (embryonic)= can make everything except the placenta
Totipotent = can make ALL types of cells including the placenta
Where do we find embryonic stem cells?
They are ‘pluripotent’ found in the inner cell mass and cultured
Where do we find tissue stem cells?
surface of the eye, brain, breast, skin, testicles, intestines, muscles, and bone marrow - theoretically they are in every tissue in small numbers - they are multipotent and can therefore only make the type of cell they belong to originally
Where do we find haematopoietic stem cells?
they are found in bone marrow and they can differentiate into any sort of blood cell including immune cells
Where do we find mesenchymal stem cells?
We find them in bone marrow - they can make anything related to bones and joints like fat, cartilage, and bone itself
How do we ‘induce’ pluripotent stem cells?
We take one somatic cell (skin in the research case) and you genetically reprogram into express genes that are only expressed during early embryonic development therefore tricking it into behaving like a pluripotent stem cell -
Then we culture the induced pluripotent stem cell in a particular ‘microenvironment’ to help it differentiate into a particular type of tissue-
Describe the sources, potency and ethical concerns/limitations with embryonic stem cells
source: inner mass of blastocyst
potency: pluripotent
ethics / limitations : requires destruction of embryo and donation requires informed consent
