lecture 26 - cellular differentiation & stem cells Flashcards
How does an embryo begin?
As a small number of equivalent/identical naïve totipotent cells that have the potential to give rise to any type of cell.
What is cell polarisation in terms of embryonic development?
When the nuclei of the cells move to one side of the cell and layer of micro vili forms on the outer sides of the cells , facing the inter uterine environment
What is the result of cell compaction in embryonic development?
The outer and inner cells begin to differentiate into the ICM (inner cell mass), and trophectoderm
What is the ICM, in terms of embryonic development?
Inner Cell Mass
What does the ICM (inner cell mass) give rise to?
Embryonic stem cells
What types of cells can embryonic stem cells give rise to?
All cell types except trophectoderm
What are trophectoderm cells?
Cells that give rise to the placenta during embryonic development.
How can the potency of embryonic stem cells be described?
Pluripotent
What does pluripotent mean, in terms of cell development?
Can give rise to a wide range of cells
In embryonic development, the progressive restriction of cell fate leads to?
The terminal differentiation of cells, so that individual cells can only form replicas of themselves and can opt change their fate.
How is the ‘fate’ of a pluripotent precursor embryonic cell decided?
Based on the genes that are turned on or off - certain genes code for certain transcription factors that allow specific proteins relevant to cell function to be manufactured.
What is the regulatory gene that controls the differentiation of an embryonic cell into a muscle cell component/myoblast?
myoD
What is the function of MyoD protein?
It is a transcription factor that allows a myoblast to develop into a muscle fibre by acting as a transcription factor to turn on genes that are relevant for muscle development (e.g. mysoin)
Where can human embryonic stem cells be harvested from?
The ICM of blastocyst embryos
What are induced pluripotent stem cells?
Cells made by reprogramming adult skin cells to become pluripotent - to mimic stem cells.
How can adult tissue stem cells be described, in terms of differentiation and potency?
Undifferentiated, multipotent
What does totipotent mean, in terms of cells?
A cell found in an early embryo that can give rise to all cell types.
What does multipotent mean in terms of cells?
Can give rise to one or a few different cell types
Are adult stem cells multi potent or pluripotent?
Multipotent
What is asymmetric division?
The division of a stem cell into a stem cell and progenitor cell (less specialised but still capable of differentiation) - two non-identical daughter cells
What is a progenitor cell?
A descendant of a stem cell that is specialised to a specific type of tissue, but can further differentiate into specific cell types
How can stem cells be used to correct single gene disorders?
By inserting a normal allele into a stem cell, a wide variety of functioning cells can be produced when they enter the body.
What 2 types of cells do not become differentiated during embryonic development?
Stem cells and Germ cells
