Concepts and Terminology Flashcards
What are the 2 types of cell fate restriction in terms of development?
Mosaic development and Regulative development
What is mosaic development?
Cell autonomous specification: Information inherited from parental cell
What is regulative development?
Conditional specification: Cell influenced by its surroundings, or position, within the embryo
Totipotent means?
Can give rise to all tissues
Pluripotent means?
Can give rise to many tissues
What is differentiation?
A restriction of potential with molecular/biochemical changes - term often used for mature cell types.
What is specification?
- Specification - what tissues will develop in an autonomous (“neutral”) environment.
What is determination?
Determination - an irreversible change in potential
What two things make up cell commitment?
Specification and determination
What is potential/ potency?
The range of tissues to which a cell can give rise.
What is competence?
The ability to respond to an inductive signal
What are the types of inducive interactions? Examples?
Permissive: In permissive interaction, the inducing tissue provides signals to an already committed responding tissue to commence differentiation.
Instructive: In instructive interaction, the inducing tissue gives instruction to commit cells to a specific pathway of development.
- Appositional
- Morphogen gradient
Growth of pancreas depends on the associated mesoderm. If in a 9-day old embryo, the pancreatic mesoderm and ectoderm are separated from one other, there will not be any additional development. But if they are recombined in a culture medium, both exocrine and endocrine cells differentiate normally. As well, instead of the pancreatic mesenchyme, if the mesenchyme from other regions like mesenchyme from salivary gland region is, substituted general pancreatic cells still differentiate. Somites which produce muscles and cartilage cells can as well induce pancreatic endoderm to develop normally. Even extracts of embryo can induce the pancreatic endoderm. All these results suggest that by 9th day of embryonic life of mouse, the pancreatic endoderm is already determined or committed and just only a non-specific signal from mesoderm is enough for it to complete the development. The mesoderm can be from any region but have to be in proximity to the endoderm.
What is a morphogen?
A diffusible molecule that triggers different cell fates at different concentrations
What do homeotic genes do?
Regulate the development of anatomical structures .
