Arches Flashcards
what is the definition of developmental biology?
study of the processes by which organs grow and develop
what are the 4 fundamental aspects of developmental biology?
- Proliferation/Growth-size
- Pattern formation: is the process by which cells in a developing embryo acquire identities that lead to a well ordered spatial pattern of cell activities
- Morphogenesis-shape
- Differentiation-type
what are dynamic, reciprocal and sequential interactions?
Sequentially = timing of events
Reciprocal = one in control then other
Dynamic = happen quickly
Tissue interactions appear to be associated with at least 2 general types of phenomena what are they?
- Instructive
- Permissive
Describe instructive
the ability of one tissue to determine specific patterns of morphogenesis and differentiation that will develop in an associated tissue
Describe Permissive (or facilitative)
the ability of an interacting tissue to provide certain conditions that is necessary for its committed partner tissue to progress to full expression of its pre-determined phenotype
What are the primary germ layers?
- Ectoderm-skin, neural tube, etc
- Mesoderm-just about everything else
- Endoderm-gut
- Neural Crest/Ecto-mesenchyme
describe ectoderm-skin, neural tube, etc
comes from the epiblast layer
describe mesoderm-just about everything else
and is from migratory cells of the epiblast layer
describe endoderm gut
come from the hypoblast layer
describe neural crest/ecto-mesenchyme
from the ectoderm that migrates into mesoderm to form structures in head and neck
describe pharyngeal arches
- Appear in 4th and 5th week
- Bars of mesenchymal tissue migrate in
- Arches separated by:
- clefts/grooves - externally
- Pouches - internal
