CSB329H1 Lecture Notes - Inner Cell Mass, Adult Stem Cell, Cell Potency
Document Summary
Lecture 2: stem cells in sponges general principles. Trophectoderm (multipotent) will differentiate to form the extra embryonic tissues (ex: placenta). Fertilization totipotent morula (all cells including placenta) blastocyst containing 2 cell lineages (trophectoderm and inner cell mass). Importance: normal development and tissue homeostasis/regeneration are dependent on stem cells the survival of multicellular organisms. Potency: the number of possible fates open to a cell. The degree of potency generally decreases during development. Stem cells must: self-renewal, ability to differentiate. Totipotent: generate a complete embryo including extraembryonic tissues. After divisions 2 fates: trophoblast cells and inner cell mass. Pluripotent: can generate any tissue in the embryo proper, but not the extraembryonic tissues (placenta). The inner cell mass makes all the 3 basic germ layers. Bipotent: nervous system stem cells, lymphoid progenitor cells (b cell and t cell). Most adult stem cells are uni/bi/multi and not pluripotent. Adult stem cells are typically restricted further than multipotent stem cells.
