BSC-2011 Lecture Notes - Lecture 8: Gastrulation, Morphogen, Neurulation
Grey crescent determines where back is going to be
Mechanisms of development:
• Maternal Determinants
• Cell to Cell interactions – cells can recognize each other and signal
each other through physical contact or chemical signaling (signals
only affect cells that have the right RECEPTORS)
• Blastopore becomes mesoderm
• Animal pole becomes ectoderm
• Vegetal pole becomes endoderm
• Invagination for gastrulation starts at dorsal lip
• Dorsal lip cells produce a morphogen
Ex: Amphibian gastrula "organizer" of Spermann and Mangold
• Some cells from dorsal lip of 1 gastrula are transplanted to the
ventral side of a second gastrula
• Transplanted dorsal lip tissue induced ventral cells to develop
uncharacteristically into a second set of dorsal features
INDUCTION
• Ability of one group of embryonic cells (organizer) to influence the
development of other cells via signal molecules (inducers) that alter
gene expression
In Frogs
• 1. Neurulation of surface ectodermal cells is induced by the
underlying NOTOCORD
• Notocord: a skeletal rod in chordates formed from dorsal
mesoderm
find more resources at oneclass.com
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Document Summary
Grey crescent determines where back is going to be. Induction: ability of one group of embryonic cells (organizer) to influence the development of other cells via signal molecules (inducers) that alter gene expression. Neurulation of surface ectodermal cells is induced by the underlying notocord: notocord: a skeletal rod in chordates formed from dorsal mesoderm, 2. Neural plate forms (a thickening of ectoderm caused by changes in cell shape: 3. Neural folds and neural groove form (changes in cell shape and adhesion cause uplifting of cells: 4. Neural tube forms once neural folds meet (eventually becomes spinal cord and brain: 5. Paired somites of mesoderm tissue flank neural tube: somites: paired blocks of mesodermal cells extending serially along neural rubeform vertebrae, ribs, muscles, mesoderm extensions split and form body cavity, 6. Neural crest cells are epidermal cells above the neural tube and these migrate to form other cell types like peripheral nerves, teeth, skull bones.
