BIOL 118 Lecture Notes - Lecture 7: Inta, Neural Tube Defect, Neural Tube
11 Dec 2015
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Document Summary
Development proceeds in ordered phases through an animal"s life cycle (fig. Bindin - tip of sperm, binds to the sperm receptors. Behind bindin there is an acrosome - contains digestive enzymes. Polyspermy - multiple sperm fertilizing an egg, undesirable bc it would give way too much dna. When released by exocytosis sperm receptors are digested and fertilization envelope forms (barrier so no other sperm come in) Sperm become hyperactive to digest the jelly layer. Water is drawn into the egg cell by osmosis, going to form the fertilization envelope. Partioning of the cytoplasmic determinants = regulatory molecules. As the zygote moves toward the uterus it is rapidly dividing. Blastocyst - hollow mammalian blastula inner cell mass - becomes embryo. Cleavage ends with the formation of a blastula or a blastocyst. Epithellal lining of digestive tract, respiratory tract, reproductive tract. Begins once gastulation is complete and they embryonic germ layers are placed.
