L20 - stem cells Flashcards
define stem cell
pluripotent cell that can differentiate into any cell type
define totipotent
can form any tissue / cell type / embryonic tissue
define pluripotent
can form any of the 3 germ layers (and therefore any of the derivatives of them)
define multipotent
cell that can give rise to cell types of specific tissues
where do embryonic stem cells come from
inner cell mass of blastocyst (4-5 days old)
what 2 things are stem cells capable of
self renewal
differentiation (daughter cells)
are embryonic stem cells multi/pluri/totipotent
pluripotent
self renewal is the _________ division of stem cells
symmetrical
differentiation is the _________ division of stem cells
asymmetrical
what is purpose of tissue stem cells
repair and maintenance in adult organisms
when does the first stage of differentiation occur during embryonic development
morula stage
what type are tissue stem cells
multipotent
where are haematopoietic stem cells located
in bone marrow
what is the function of haematopoietic stem cells (HSC)
can produce
1. lymphocytes
2. blood cells
(blood renewal)
where are mesenchymal stem cells located
bone marrow
adipose tissue
umbilical cord
function of mesenchymal stem cells
form
- bones
- cartilage
- tendons
- adipocytes
what do patients have to be treated with before HSC can be collected and why
cytokines, they move stem cells from bone marrow to blood
what is the function of neural stem cells
form new
- neurons
- astrocytes
- oligodendrocytes
how can stem cells be identified
- able to differentiate
2. cells that proliferate for > 6 months without differentiating are pluripotent (long term self renewal)
describe what is meant by stem cell niche
Microenvironment around stem cells that provides support and signals regulating self-renewal and differentiation
regulates SC behaviour
how are induced pluripotent stem cells produced
- somatic cell transduced with pluripotent factors (OCT4 , SOX2, KLF4 , cMYC )
- produces IPSCs
what are the yamanaka factors
pluripotent factors OCT4 SOX2 KLF4 cMYC
advantages of IPSCs?
- more ethical than embryonic SCs
2. can be generated from any somatic cell
applications of stem cells
- treat blood diseases
- make skin - treat burns
- repair damaged cartilage / bone (mesenchymal SCs)
what do embryonic stem cells express?
NANOG
OCT4
SOX2.
what are stem cells found attached to
niche cells
purpose of niche cells
prevent stem cells differentiating
