Post Embryonic Development: Metamorphosis, Regeneration, Aging Flashcards
what are the 3 stages that occur after the developmental stages?
- metamorphosis
- regeneration
- aging
define metamorphosis
unrecognizable, subtle changes within an organism
metamorphosis is generally under
hormonal control
during metamorphosis it is primarily
thyroid hormones working to activate or inactivate transcription
during metamorphosis, tissues under the influence of hormones will lead to
- degeneration of some
- differentiation of others
define regeneration
post-embryonic restoration of missing tissues
regeneration requires the presence of
intact and functioning nervous systems
what are the 4 approaches to regeneration
- stem cells
- de-differentiation
- morphallaxis
- compensatory regeneration
explain de-differentiation
taking adult structures back to the stage of undifferentiated cell to become respecified
morphallaxis is the
regeneration of specific tissues due to loss/death of existing tissues
explain compensatory regeneration
the proliferation of differentiated cells which maintain their specific function
blastema is a
de-differentiated cell mass
a cell mass is composed of….
these are essentially components of the
- bone cells
- cartilage cells
- myocytes
- nerve cells
- fibroblasts
mesenchymal stem cells
regeneration of blastema cells depends on the
presence of nerves
with regeneration of blastema cells, there’s also a quantitative requirement such as
the minimum # of nerves needed