FORM & FUNCTION (Stem Cells) Flashcards
Ectoderm eventually becomes
-outer surface
-CNS
-neural crest
Mesoderm eventually becomes:
-dorsal
-paraxial
-intermediate
-lateral
-head
Endoderm eventually becomes:
-digestive tube
-pharynx
-respiratory tube
Germ cells become:
-male: sperm
-female: egg
Main cellular processes that are key to successful development are:
- Cell proliferation
- Differentiation
- Morphological Changes and Cell migration
- Apoptosis
*elicited and/or regulated by factors
Cell proliferation:
-an increase in cell number due to mitosis
Differentiation:
-a gradual process by which specialized cell types develop from a pool of cells
Apoptosis:
-programmed cell death
-mediated via enzymes including caspases and DNases
What are the additional key decisive factors/processes in embryonic development?
-cell-to-cell communication
-signaling pathways
-induction and competence
-adhesion and migration
-morphogens
-genes
-transcription factors
Signaling pathways:
-11 main ones involved in development
-each signal is transmitted in a LINEAR MANNER and act on a single response element in target genes
-specific patterns of signaling for a given species
-changes elicited by these signals during development are IRREVERSIBLE
Examples of signalling pathways involved in development:
-Notch
-Wingless (Wnt)
-transforming growth factor (TGF-beta)
-fibroblast growth factor (Fgf)
Induction:
-process by which a particular group of cells influences the fate of an adjacent group of cells
-generally mediated via paracrine or contact-dependent signaling
Competence:
-refers to ability of a cell to respond to an inductive signal
-competent cell must express the receptors for the inducer(s)
Ex. response of a group of cells to a transcription factor
Cell adhesion is mediated by:
-cadherins and integrins
Cadherins in one cell:
-interact with cadherins in adjacent cells
Adherins:
-help with the adhesion of cells to various ligands
Heavy cell migration during development:
-cells use different forms of movement for migration depending on the stage of development
What are determinants of cell migration?
-molecular composition of the ECM and matrix architecture of cells
Morphogens:
-a substance that can determine the fate of a cell/cell’s differentiation by way of its presence in the cellular microenvironment
-effects are CONCENTRATION dependent
-elicit stimulatory or inhibitory effects
Example of a morphogen:
-signaling molecules, sonic hedgehog (Shh) is important for formation of spinal cord
Effects of Shh are dependant on:
-its concentration
-duration of exposure
-interaction with other target genes and/or signals/pathways
Chromatin:
-DNA and protein
*structure has a heavy influence on gene expression
Epigenome:
-a determinant of how cells remember their identity
-comprises of processes and signals
Epigenome comprises of processes and signals examples:
-DNA methylation
-histone modification
-other factors including small RNAs