development and stem cells Flashcards
what are the two different populations of cells which develop during blastocyst formation
trophoblast cells (outer cells) , they pump sodium in from the outside which automatically brings water in with it to the inner surface to form a blastocoel cavity. the trophoblast cells will eventually give rise to the placenta .
the inner cells are pushed to the one side of the cavity (because the embryo isn’t getting any bigger) to form the inner cell mass and will give rise to the embryo. at this stage the embryo is called a blastocyst
blastocyst information
3-6 days after the egg is fertilised , it forms a hollow ball of around 100 cells known as the blastocyst . the blastocyst is filled with fluid and contains a small number of cells (around 30) inside , forming the inner cell mass. the ICM will eventually form the embryo proper and some of the extra - embryonic membranes surrounding the embryo .
the outer trophoblast (trophectoderm) forms part of the placenta. blastocyst implants into the uterine wall.
what is gastrulation
a single layer undifferentiated blastocyst is reorganised into a trilaminar structure . highly co-ordinated cell movement process - results in rearrangement and repositioning of cells .
what is a germ layer
a germ layer is a primary layer of cells that form during embryogenesis .
name the three germ layers
ectoderm - gives rise to the skin and the nervous system
mesoderm- is found between the ectoderm and endoderm and gives rise to muscle , cartilage, blood and bone
endoderm- gives rise to the digestive system and respiratory system
what is organogenesis
it is the process by which the ectoderm , endoderm and mesoderm develop into the internal organs.
it occurs at distinct times in development to give individual functional structures .
what is organogenesis
it is the process by which the ectoderm , endoderm and mesoderm develop into the internal organs.
it occurs at distinct times in development to give individual functional structures .
what are stem cells
stem cells are unspecialised cells that can differentiate into specialised cells but retain the ability for self renewal.
what is totipotency
the ability of a cell to develop into all cell types including the extra -embyronic membranes forming the placenta
what is pluripotency
a stem cell that has potential to differentiate into any of the three germ layers but not the extra embryonic membranes
what is multi potency
cells which have the potential to differentiate into multiple , but limited cell types
what is oligopotency
the ability of stem cells to differentiate into a few cell types
what is unipotency
stem cell has the capacity to differentiate into only one cell type
therapeutic use of stem cells
stem cell therapy is the use of stem cells to treat or prevent a disease or condition. bone marrow transplant is a form of stem cell therapy . the patient may need to use immunosuppressants when getting stem cell therapy because their immune system may attack the stem cells
what is autologous stem cell transplantation
these cells are collected in advance and returned at a later stage . they are used to replace stem cells that have been damaged by example high doses of chemotherapy used to treat leukaemia .
