Developmental Bio Flashcards
Define pre formation
Epigenesis
Which did Aristotle prefer
1) organs+tissues preformed and correctly positioned and fertilised egg - simply enlarge
2) organs and tissue formed gradually , complexity of embryo increasing - preferred by Aristotle
What did Anthony’s van Leeuwenhoek discover, and what did this make popular in Late 17th century?
Whats the homunculus theory ?
What did it not explain?
Axis - give 3 examples
Line across embryo w morphological difference , e.g. rostal-caudial ( head- tail / anterior/ posterior), dorsal- ventral ( back- belly) , left-right.
Cell lineage
Also similar to what
Similar to fate mapping or family tree - shows ancestry of cell in embryo /tissue/organ . Mainly used in experiments where cell followed and observed to find final fate. Cell marked or observed.
Commitment - 2 meanings depending On scientist.
Also similar to what
Determination - irreversible decision to differentiate in specific direction.
Some say cell committed to partical fate - maybe reversible.
Competence , definition and 3 things it depends on.
Ability of cell to respond to inducing signal.
Depends on - expression of appropriate receptor for inducing factor - intact signal transduction cascade - epidemic state of target genes (may respond or not )
Cytoplasmic determinant , what is it usually ?
Substance localised to part of egg/blastomere - assymtrically distributed during cell division. Guarantees specific commitment for cell.
Usually Transcription factor.
Determination
Irreversible commitment to specific cell fate- made by stem cell. Same developmental potential as cell fate.
Differentiation
Cell acquired final characteristics. Manifestation of cell fate. Cell has clearly defined morphology and histological type.
Embryonic induction
Signalling interaction between inducing and responding cells , where responding cells undergo xhange of fate. Inducing factor used.
Fate
Developmental potential.
Fate map
Morphogenesis give 2 examples
Formation of bio structure by changing cell relationships.
Gastrulation and neurulation
Morphogen
Forms conc gradient across morphogenic field - evokes different cells fates at diff conc.s must result in atleast 3 cell types - otherwise an inducing factor.
Morphogenetic field
Can develop independently w out instructive influences. Capable of regulation - portion can reconstitute whole field. As developmental proceeds - fields subdivided- become smaller and more numerous.
Organiser
Embryonic region emitting instructive signals for regional specification within morphogenic Field - usually morphogen.
Pattern formation
Includes regional specification, cell movements and sorting processes.
Polarity
Regional differences in cell cell commitment along axis of morphogenitic field.
Positional information
Provides spacial info across MF
Potency
Regeneration
Ability of MF or tissue to replace missing parts
Regional specification vs specification
Regulation
Stem cells
What are the 7 main stages of development
What are the 3 germ layers
Total of 11 tissue types- which germ layer does each develop from
What happens to flexibility of differentiation as complexity increases- why ?
What is this process called
Complexity increases - variety of things that cell can differentiate into or flexibility decreases
Lineage restriction
Stages of potency of stem cells and what they mean and examples (5)
Identify all vertebrate body plan sections, position, function, and remember they are not differentiated yet just stem cells.
What about amniotic membrane and umbilical chord?
Stem cells divide into what 2 types of cell? Why is this essential? If it’s just stem cells than what happens? If it’s just differentiated cells then what happens?
What’s cell commitment ? Why is it significant ? What role does lineage restriction play ?
Give example of flow chart for epiblast into skeletal muscle - w all options along the way
What are the 3 stages of commitment? Explain each .Which stages are reversible and what’s not?
3 mechanisms of cell commitment ?
Who discovered determinants and when?
Localised determinants are what type of development ?
How do they work ?
How did the discovery of yellow cytoplasm contribute to determinants ?
What and by who and when was the first experiment of embryology ? Method and results, conclusions and suggested mechanisms ?
What’s regulative development ?
What experiment was done related to it? By who and when? Why did it disproved determinants theory ?
What experiment did Spemann do in 1903 and what did it prove?
What did roux do wrong in his experiment ?
What was hilde mangold’s experiment on embryonic induction?
Method, results and conclusion ?
Label all parts of a diagram showing neural induction.
Define neural induction
How does a cell fate form a neurone? Which of the 3 layers is it first restricted to? Next step? One after?(which part of NS), then finally cell splits into neuron and what ?
When do cytoplasmic determinants vs induction play a role throughout the process?
What are the 4 developmental signals?
