| A | B |
|---|
| aboral | distant from the mouth |
| actin | building block of intermediate filaments |
| activin | TGF-beta like mesodermal inducer |
| allophenic mice | mouse embryos derived from fusion of two embryos into a single individual |
| animal pole | end of egg with least amount of yolk |
| apical surface | side of epithelium exposed to open space |
| area opaca | region of bird blastoderm that abuts directly onto yolk |
| area pellucida | central portion of embryo underlain by subgerminal cavity |
| asters | microtubules emanating from centrosomes of animal mitotic apparatuses |
| basal lamina | acellular membrane secreted by epithelium to separate the basal surface from other tissues |
| blastocoel | fluid-filled cavity in blastula |
| blastocyst | mammalian blastula |
| blastocyst cavity | mammalian blastocoel |
| blastoderm | disk of embryonic cells in birds |
| blastomere | cell of embryo |
| blastopore | site of invagination during gastrulation |
| blastula | general term for spherical embryo with fluid filled cavity |
| conceptus | blanket term for zygote, embryo, or fetus |
| cleavage | cell division |
| cleavage furrow | invagination of cell membrane occurring during cytokinesis |
| compaction | when blastomeres flatten and cannot be distinguished from each other |
| contractile ring | cytoskeletal fibers that help create cleavage furrow |
| cytokinesis | division of cytoplasm |
| dauerblastula | highly ciliated permanent blastula forming from animal cells of sea urchin |
| desmososme | intercellular junction found in spot and belt forms |
| DNA methylation | addition of -CH3 groups to DNA to regulate gene expression |
| ectoderm | outermost layer of trilaminar embryo - forms brain and skin |
| endoderm | innermost layer of trilaminar embyro - forms gut |
| epiblast | layer of bird blastula furthest from the yolk |
| FGF | induces ventral mesoderm |
| gray crescent | region of frog embryo with intermediate amounts of pigment |
| holoblastic cleavage | cleavage with complete cytokinesis |
| hypoblast | layer of bird blastula closest to yolk |
| inner cell mass | cells in mammalian blastula that give rise to embryo |
| isolecithal egg | egg with yolk evenly distributed through cytoplasm |
| karyokinesis | mitosis or meiosis |
| macromeres | large blastomeres |
| maternal effect gene | controlled by mRNAs inserted into egg prior to fertilization |
| marginal zone | amphibian blastula cells in the region where blastocoel roof and basement meet |
| meroblastic cleavage | cleavage with incomplete cytokinesis |
| mesenchyme | multipotent cells that move by amoeboid motion |
| mesoblast | mesoderm in birds |
| mesenchyme blastula | sea urchin blastula following invagination of former micromeres |
| mesolecithal egg | egg with intermediate amount of yolk |
| micromeres | blastomeres that are very small |
| morula | embryo that is a solid sphere of cells |
| mosaic development | separation of cells in embryo lead to incomplete development of embryos |
| M phase | cell cycle phase of karyokinesis |
| Nieuwkoop center | dorsalizing region of frog embryo |
| oligolecithal egg | eggs with little yolk |
| primary mesenchyme | mesenchyme derived from micromeres in sea urchins |
| prospective fate | the type of cell from an embryonic cell that is left undisturbed |
| prospective potential | the range of tissues that will arise from a cell if it is left undisturbed in embryo |
| regulative development | generation of two complete embryos by separating an embryo |
| Spemann organizer | dorsal lip of amphibian blastopore |
| S phase | phase of cell cycle where DNA is replicated |
| subgerminal space | area between bird egg yolk and hypoblast |
| telolecithal egg | egg with yolk concentrated into one end |
| trophoblast | outer layer of mammalian blastula - becomes extraembryonic membranes |
| uteroglobin | protein from uterine fluid found in mammalian blastocoel |
| vegetal plate | flattened surface of sea urchin embryo where blastopore originates |
| vegetal pole | end of embryo with least amount of yolk |
| zygote | diploid cell formed from the union of sperm and egg cells |
