logging in or signing up Embryology Nathaniel Download Post to : URL : Related Presentations : Let's Connect Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Copy embed code: Embed: Flash iPad Dynamic Copy Does not support media & animations Automatically changes to Flash or non-Flash embed WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 7156 Category: Entertainment License: All Rights Reserved Like it (9) Dislike it (0) Added: November 15, 2007 This Presentation is Public Favorites: 1 Presentation Description No description available. Comments Posting comment... By: alhayagem (31 month(s) ago) nice slides Saving..... Post Reply Close Saving..... Edit Comment Close By: Consultants (50 month(s) ago) i would like to hoin your group Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript ANIMAL DEVELOPMENT : ANIMAL DEVELOPMENT THE STAGES OF EARLY EMBRYONIC DEVELOPMENTPREFORMATION vs EPIGENESIS: PREFORMATION vs EPIGENESISFERTILIZATION: FERTILIZATION Creates diploid zygote Triggers embryonic development The process: Sperm penetrates egg membranes, head is ingested, nuclei fuse. Egg’s metabolic machinery is activated, meiosis is completed. Egg raises barriers to entry of other sperm. Fertilization membrane lifts off egg--‘slow block to polyspermy’ Acrosomal, Cortical Reactions: Acrosomal, Cortical ReactionsCortical Reaction: Fertilization Envelope: Cortical Reaction: Fertilization EnvelopeAfter Fertilization: After Fertilization Membrane lifted off zygoteCleavage Determinants: Cleavage Determinants Distribution of yolk Even distribution (isolecithal) Uneven distribution (telolecithal) Animal pole Vegetal pole Holoblastic cleavage (mammals, frogs, sea stars) Meroblastic cleavage (fish, birds, reptiles) Deuterostome patternFormation of a Blastula: Formation of a Blastula Cell division continues until a hollow ball of cells forms One cell layer thick Fluid filled space is a blastocoel Indentation of blastopore ends this stage Events of Gastrulation: Events of Gastrulation Three primary germ layers are established. Basic body plan is established, including the primary body axes. As a result of the movements of gastrulation, cells are brought into new positions, allowing them to interact with cells that were initially not near them. This paves the way for inductive interactions, which are the hallmark of neurulation and organogenesis. 4. Archenteron may appear Radial Cleavage: Radial Cleavage http://www.uleth.ca/bio/bio1020/images/star8.jpg Sea StarSea Star Development: Sea Star Development http://www.uleth.ca/bio/bio1020/images/star8.jpg BlastulaGastrulation: Gastrulation archenteronPoles, Cleavage: Poles, CleavageFrog Cleavage: Frog CleavageFrogHoloblastic Cleavage: Frog Holoblastic Cleavage http://www.uleth.ca/bio/bio1020/images/frog12.jpgFrog Blastula: Frog Blastula http://www.uleth.ca/bio/bio1020/images/frog10.jpgGastrulation: Gastrulation http://www.uleth.ca/bio/bio1020/images/frog8.jpg archenteronNeurulation: Neurulation http://www.uleth.ca/bio/bio1020/images/frog5.jpgRate of Cell Division: Rate of Cell DivisionEARLY CLEAVAGE 2-64 cells: EARLY CLEAVAGE 2-64 cellsMorula Blastula: Morula Blastula 16-64 cells 128 cells Blastocoel 256 cellsDevelopment in a Chick Embryo: Development in a Chick Embryo http://www.lawrence.edu/dept/biology/embryoatlas/stage18whole1.jpgNeurulation in a Chick (24 hr): Neurulation in a Chick (24 hr) http://www.uoguelph.ca/zoology/devobio/24hrchck/24ck2.htmChick Embryo 72 hrs: Chick Embryo 72 hrs http://www.uoguelph.ca/zoology/devobio/72hrchck/72ckintr.htm You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.