L11 - Pharyngeal Arches Flashcards
What structures characterize the head of the developing mammalian embryo?
Pharyngeal arches
Which layers are represented in pharyngeal arches but organized differently from the other body regions?
Germ Layers
- endoderm
- mesoderm
- ectoderm
How do monozygotic twins form?
Within the zona pellucida, we get the formation of:
- 2 blastocysts
The 2 blastocysts merge and we get 2 inner cell masses within 1 blastocyst.
The blastocyst divides as it emerges from the zona pellucida.
List 4 cellular responses that are induced by extracellular signals.
1) Morphological Changes of Cells
2) Division of cells
3) Apoptosis
4) Differentiation of Cells
What is paracrine signalling?
When one cell releases messenger molecules that act on another cell in the body.
What is autocrine signalling?
When one cell releases messenger molecules that act on itself.
What is contact-dependent signalling?
When two cells must have receptor-ligand contact to have an effect on each other.
What gives rise to the epidermis and it’s associated glands?
Surface Ectoderm
What develops into the CNS?
Neural Tube
What forms the neural tube?
Neuroectoderm
Which germ layer do neural crest cells arise from?
Ectoderm (Neuroectoderm)
What are neural crest cells?
Migratory cells that move to other parts of the body and give rise to a diverse cell lineage.
- melanocytes, cartilage, smooth muscle, bone etc.
What do neural crest cells mix with when they migrate to the pharyngeal arches and form head mesenchyme?
Mesoderm
What is the term for the process which permits migration of neural crest cells to different regions of the developing embryo?
Epithelial-mesenchymal transition (EMT)
What influences EMT (epithelial-mesenchymal transition) of neural crest cells?
EMT Effectors
List some EMT effectors.
Growth Factors
Cytokines
ECM