LS2 lect2 - Life Sciences 2 September 3 2010 EMBRYOLOGY ANNOUNCEMENTS Labs www.section.fas.harvard.edu SIGN UP TODAY enrollment questions Dr Jennifer

LS2 lect2 - Life Sciences 2 September 3 2010 EMBRYOLOGY...

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EMBRYOLOGY Life Sciences 2 September 3, 2010
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ANNOUNCEMENTS Labs: SIGN UP TODAY!!!!!!!!!!!! enrollment questions: Dr. Jennifer Carr [email protected] My office hours: Tuesday 1-2, and by appointment Peabody 53 [email protected]
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LS2 running group SUNDAY MORNING 10:00 Weeks Bridge ALL LEVELS WELCOME ESPECIALLY NON-RUNNERS (YET)!
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THIS LECTURE MAIN POINTS: 2. What is the basic body plan? 1. How do we go from a single cell to awhole body?
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1. Embryology helps explains why and how body gets its shape 1. The body is largely a set of folding tubes and sheets , each of which derives from three initial layers of cells 2. The body’s many parts fit and work together because of how they grow: a hierarchical (branching) process with many interactions between units
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2. Embryology helps explain mechanisms by which evolution creates new forms, including humans Basic answer: we are essentially fish, which, in turn, are just evolved worms (NEXT LECTURE)
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1. First stages of life 2. Formation of major cell lines 3. Formation of basic body plan Neural tube Central axis Gut tube and body cavity Outline
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The Beginning Part 1
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We begin, of course, as a single cell: the zygote Human body: ! 350 different kinds of cells, each with: membrane cytoplasm nucleus All cells have four basic functions: multiplication movement change character (differentiate) signal to other cells
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Zygotes derive from two gamete cells sperm 2x (diploid) 4x 4x 2x 1x 2x 1x x x Meiosis I Meiosis II Spermatogenesis Oogenesis egg 1x (haploid)
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Fertilized zygote Pronuclei (n=2) 1. Fertilization: 12-24 hours after ovulation 2. One-cell stage: two pronuclei fuse (zygote) 3. First cleavage : two-cell stage ! 30 hours post ovulation
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2 cell stage
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  • Fall '10
  • AndrewA.Biewener,PeterT.Ellison,andDanielE.Lieberman
  • Developmental Biology, Neural tube, Mesoderm

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