Embryonic Development of Multicellular Organisms

Cell Division: large # identical cells through mitosis
Cell Differentiation: cells become specialized in structure & function
Morphogenesis: “creation of form” – organism’s shape
Determination: irreversible series of events that lead to cell differentiation

Totipotent cells: can form all the cell types in a body, plus the extraembryonic, or placental, cells. * Embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent.
Pluripotent cells: can give rise to all of the cell types that make up the body * Embryonic stem cells are considered pluripotent.
Multipotent cells: can develop into more than one cell type, but are more limited than pluripotent cells * Adult stem cells and cord blood stem cells are considered multipotent.

Cytoplasmic determinants: maternal substances in egg distributed unevenly in early cells of embryo
Induction: cells triggered to differentiate
Cell-Cell Signals: molecules produced by one cell influences neighboring cells
Pattern formation: setting up the body plan (head, tail, L/R, back, front)
Morphogens: substances that establish an embryo’s axes
Homeotic genes: master control genes that control pattern formation