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| - is a dramatic reorganization of the hollow blastula into a two-layered embryo called a gastrula |
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| - when the organ rudiments form from the 3 germ layers after gastrulation |
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| - a hollow blastula that forms into a two or 3 layered embryo |
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| - particular species chosen for research into broad biological principles because it represents a larger group and & easy to grow in lab |
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| - discharge of hydrolytic enzymes from the acrosome, a vesicle at the tip of the sperm, when the sperm aproaches or contacts the egg |
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| - vesicle at the tip of the sperm that contains hydrolytic enzymes and other proteins that help sperm reach the egg |
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| - depolorization of the egg plasma membrane that begins within 1-3 seconds after a sperm binds to an egg membrane protein. The depolorization lasts about one minute and prevents add'l sperm from fusing with the egg during that time |
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| - formation of the fertilization envelope & other changes in an egg's surface that prevent fusion of the egg with more than one sperm. The slow block begins 1 min after fertilization |
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| - extracellular matrix that surrounds the egg of a mammal |
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| - hollow ball of cells marks the end of the cleavage stage during early embryonic developement in mammals |
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| - an early embryonic cell arising during the cleavage stage of an early embryo |
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| - fluid-filled cavity that forms in the center of a blastula |
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| - nutrients stored in the egg |
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| - the end of the egg in the part of the hemisphere where the yolk is most concentrated that is opposite of the animal pole |
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| - part of the end of an egg in the hemisphere where the yolk is least concentrated & is opp. to vegetal pole |
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| - type of cleavage where the egg completely divides, this occurs in eggs that have little to moderate amount of yolk |
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| - type of cleavage where the yolk-rich egg doesn't divide all the way |
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| one of the 3 main layers in a gastrula that will form the various tissues and organs of an animal body |
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| - outer most of the 3 primary germ layers in animal embryos, gives rise to the outer covering and in some phyla the nervous system, inner ear & lens of the eye |
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| - inner most of the 3 primary germ layers in embryonic develop. lines the archenteron & gives rise to the liver, pancreas, lungs & the lining of the digestive tract |
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| - middle primary germ layer in a tripoblastic animal embryo that develops into notochord, lining of coelom, muscles, skeleton, gonads, kidneys & most of the circulatory system |
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| - endoderm lined cavity, formed during gastrulation, that develops into the digestive tract of an animal |
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| - in a gastrula, the opening of the archenteron that typically devlops into the anus in deuterostomes and the mouth of protostomes |
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- blastula stage of mammalian embryonic development consisting of an inner cell mass, a cabity, & an outer layer, the trophoblast.
- in humans it forms 1 week after fertilization |
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| - in the clade of tetrapods named for the amniotic egg which contains special. membranes, including fluid-filled amnion that protect embryo. Amniotes include mammals as well as birds & reptiles |
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| - cellular & tissue base process in which an animal body takes shape |
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| - series of cell & tissue movements in which the blastula- stage embryo folds inward producing a 3 layered embryo the gastrula |
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| - longitudinal flexible rod made of tightly packed mesodermal cells that runs along side the anterior- posterior axis of a chordate in the dorsal part of the body |
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- tube of infolded ectodermal cells that runs along the anterior-posterior axis of a vertebrate, just dorsal to the notochord
- gives rise to central nerv. system. |
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| - when cells or groups of cells become specialized in structure or function |
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