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| the discharge of hydrolytic enzymes from the acrosome, a vesicle in the tip of the sperm, when the sperm approaches or contacts an egg |
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| a vesicle in the tip of the sperm containing hydrolytic enzymes and other proteins that help the sperm reach the egg |
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| the depolarization of the egg plasma membrane that begins within 1-3 seconds after a sperm binds to an egg membrane protein. the depolarization last about a min to prevent additiona sperm from fusing with the egg during that time |
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| the formation of the fertilization envelop and other changes in an egg's surface to prevent fusion of the egg with more than one sperm it begins about one minute after fertilization |
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| a structure formed by the egg's extracellular matrix |
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| lifts the vitelline layer away from the egg and hardens the layer into a protective fertilization envelope |
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| the extracellular matrix of an egg |
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| the succession of rapid cell divisions without significant growth during early embryotic development that converts the zygote to a ball of cells |
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| a hollow ball of cells that mark the end of the cleavage stage during early embriotic development in animals |
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| nutrients stored in an egg |
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| the point at the end of an egg in the hemisphere where most yolk is concentrated |
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| the point at the end of an egg in the hemisphere where the least yolk is concentrated |
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| a type of cleavagein which their is complete division of the egg; occurs in eggs with little yolk like the sea urchinsos a moderate amount of yolk such as the frog |
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| reffering to a type of cleavage in which there is incomplete division of a yolk-rich egg, characteristic of avian development |
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| in animal development, a series of cell and tissue movements in which the blastula-stage embryo folds inward, producing a three layered embryo, the gastrula |
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| an embriotic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm |
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| one of the three main layers in the gastrula that will form the various tissues and organs of an animal body |
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| the outermost of the three primary germ layers in animal embryos; gies rise to the outer covering and, in some phyla, the nervous system, the inner ear, and the lens of the eye |
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| the innermost of the three primary germ layers in animal embryos; lines the archenteron and gives rise to the liver, pancreas, lungs and the lining of the digestive tract in species that have these structures. |
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| the middle primary germ layer in the triploblastic animal embryo; develops into the notochord, the lining of the coelom, muscles, skeleton, gonads, kidneys, and most of the circulatory system in species that have these structures |
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| the infolding of a sheet of cells into the embryo |
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| in the gastrula, the opening of the archenteron that typically develops into the anus in deuterostomes and the mouth in protostomes |
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| a thickening along the future anterior-posterior axis on the surface of an early avian or mammalian embryo, caused by a piling up of cells as they congregate at the midline before moving into the embryo |
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| the blastula stage of the mammalian embryonic development, consisting of the inner cell mass, a cavity, and an outer layer, the trophoblast. In humans it forms one week after fertilization |
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| an inner cluster of cells at one end of the mammalian blastocyst that subsequently develops into the embryo proper and some of the etraembryonic membranes |
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| the outer epithelium of a mammailan blastocyst, it forms the fetal part of the placenta, supporting embryonic development but not forming part of the embryo proper |
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| one of four membranes (yolk sac, amnion, chorion, and allantois) located outside the embryo that support the developing embryo in reptiles and mammals |
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| mammals and reptiles including birds |
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| one of the extraembryonic memebranes that contain fluid for the embryo |
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| disposes of wastes in the reptilian egg, is incorporated in the umbilical cord in mammals |
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| a rod that extends along the dorsal side of the chordate embryo |
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| a process in which a group of cells or tissues influence the developmet or another group through close range interactions |
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| a tube of infolded ectodermal cells that runs along the anterior-posterior axis of a vertebrate, just dorsal to the notochord. it will give rise to the central nervous system |
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| one of the series of blocks of mesoderm that exist in pairs just lateral to the notochord in a vertebrate embryo |
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| a rearrangement that causes a sheet of cells to become narrower(converge) while it becomes longer(extends) |
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| play a key role in cell migration by promoting interaction between pairs of cells |
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| diaphrams showing the structures arising from each region of an embryo |
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| the two blastomeres of a frog can each develop into all the different cell types of the species |
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| the process governing the arragements of tissues and organs in their characteristic places in three-dimensional space |
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| molecule cues that control pattern formation, tell a cell where it is with respect to animal's body axes and help to determine how the cell and its descendants will respond to molecule signaling |
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| apical ectodermal ridge (AER) |
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Definition
| a thicken area of ectoderm at the tip of the bud. secretes a protein signal called fibroblast groth factor that promotes the limb-bud outgrowth |
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| zone of polarizing activity (ZPA) |
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| a specialized block of mesodermal tissue, regulates development along anterior-posterior axis of the limb |
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