terminally differentiated cells are often found in the following stage of the cell cycle
G0
slide 19 ( During differentiation the cell usually exits the cell cycle and can remain in a G0 phase)
unique property of embryonic stem cells?
she skipped ..
embryonic stem cells are typically derived from which stage of embryonic development ?
blastocyst
pluripotent stem cells can give rise to
all types of tissue except extraembryonic tissue
pluripotent stem cells can give rise to
all types of tissue except extraembryonic tissue
what is the name of the process by which embryonic stem cells specialized into specific cell types ?
differentiation
an example of a totipotent cell is..
a fertilized cell (can find at the end of this doc)
a differentiated cell is characterized by
having a specializedfunction
ESC can be found in ..
innercellmass of blastocyst
STEM CELLS
differentiate —>can become a specialized cell (differentiated cell types_)
proliferate —> become another stem cells (replace themselves) undifferentiated
MEDICINE
Limitations
non individualized - treat ppl the same way
body damage from injury/illness - permanent and untreatable … lead to stroke or heart attack
supply does not equal demand bc more demand… than can supply
organ donors limited
tissue rejection
diseases injuries divided into 3 PROBLEMS (what can go wrong in cells?)
too much cell division
ex. tumors
too little cell division
ex. spinal cord injury, weakened heart muscles
abnormal cell function
ex. hemophilia, inability of liver cells to make right amount of clothing factors
TREATMENT OPTIONS
traditional: surgery
new: tissue renewal / stemcell therapy
how can stem cells be applied or used in medicine? what are the benefits?
change treatment options
more individualized treatments — potential
disease research —opportunity
CELL DIFFERENTIATION
CELL BECOMES SPECIALIZED CELL
cell usually exits the cell cycle, remains in a G0 phase
bodies = made up of trillions of cells
specialized functions
undergone differentiation
**DAUGHTER CELLS DIFFERENTIATE ( D FOR DAUGHTER AND DIFFERENTIATE)
CELL PROLIFERATION
cell divides into two cells…goes through cell cycle
cell division/ replication (replicate via celldivision)
divides into 2 daughter cells
**STEM CELLS REPLICATE
considered undifferentiated
no specialized characteristics
CELL CYCLE
mitotic phase
(determine m, g1, g2, s, resting, interphase) *
PROLIFERATION: divides into 2 cells
DIFFERENTIATION: cell usually exits cell cycle and remain in G0 phase .. STOP PROLIFERATING.
STEM CELL CHARACTERISTICS
stem cells
cells that act as reservoirs for new replaces needed to replace damaged or dying cells
can differentiate and proliferate
can multiply when called upon
TYPES OF STEM CELLS (7)
Embryonic stem cells (ES cells)
pluripotent (can dif into any cell in body)
come from early embryo (blastocyst)
Adult stem cells
multipotent (multiple types of cells) or unipotent
cells in bone marrow —> blood cells …present
ex. ASC, MSC, HSC
Fetal stem cells
multipotent
Umbilicalcord stem cells
multi or pluri potent
Nuclear transplant stem cells
pluripotent
Inducedpluripotentstem cells (iPS cells)
pluripotent or multipotent
Parthenogenetic stem cells
pluripotent
POTENCY OF STEM CELLS
Pluripotent - can become/differentiate into any cell in the body .. liver, heart, lung EXCEPT EXTRA-EMBRYONIC CELL/PLACENTA … very valuable . come from an egg… THINK PLURAL
Multipotent - isolate stem cell from fetus .. multiple types of cell not just any cell
Unipotent (progenitor) - develop into tissues
Totipotent - any cell and embryonic tissue ex. fertilized egg
Embryogenesis steps
embryonic stem cells aka ES cells come from early stage embryos
ovulated oocyte
fertilization
zygote forms
cleavage
morula —> blastula
Morula to blastocyst stage
morula —> blastula
6. blastocyst formation followed by implantation
day 14 : blastocyst develops into a multilayered gastrula. the embryo enters the uterine epithelium.
all tissue in the body comes from inner cell mass (ICM) of the 5-7 day old blastocyst
ICM eventually develops into the gastrula (day 14-16)
gastrula has 3 germ layers: endoderm, mesoderma, ectoderm
endoderm
forms soft tissues like pancreas and liver
mesoderm becomes muscle (including the heart), blood, bone
ectoderm
forms skin and nerve cells
cells in the ICM are pluripotent.
after the blastocyst stage, and once embryo reaches the gastrula stage, the cells are no longer pluripotent but instead are multipotent (cells of specific tissues).
Isolation of ES cells
egg state
blastocyst stage
ES cells are isolated from the ICM cells in blastocysts
implantation
gastrula stage
culturing ES cells
cleavage stage embryo
cultured blastocyst
isolated innercellmass
irradiated mouse fibroblast feeder cells
cell dissociated and repeated
new feed cells
established embryonic stem cell cultures (in a dish)
ES cells have the ability to differentiate into specialized cell types.