BIO 32 47 33.txt

  1. Fertilization
    only nucleus enters
    whole sperm enters
    fast block to "polyspermy"
    slow block
    • - sea urchin
    • -mammals
    • -triggers opening of Na+ channels in egg cellmembrane
    • -1. ERrelases Ca2+ in egg cell 2. cortical granuels move and fuse w/plasma membrane 3. fertilization envelope
  2. totipotent
    Development(6 steps)
    • -"total potential" to be any cell
    • -many potential to be a cell
    • -embryo takes form
    • 1. gamete formation 2.fertilization 3.cleavage(cell division,mitosis)4.Gastrulation(morphogenesis) 5. organ formation(differentiation)
    • 6. Growth and tissue formation(differentiation)
  3. Cleavage
    solid ball of cells
    Cell signaling
    archenteron, blastopore, dorsal lip
    • -mitotic division of zygote w/o growth , uneven cytoplasm division, seals developmental fate of cells, cells get smaller w/division
    • -morula
    • -figure where cell destined,molecules determine what genes on and off
    • - hollow fluid filled ball, successive divisions form it, polarity up v. down established
    • -gut and tissue layers develop(rearrange blastula to form a 3 layered embryo w/ primitive gut)
    • -forms endoderm embryonic gut, at sperm penetration point, organizing center for development
  4. germ layers
    1. ectoderm
    2. endoderm
    3. mesoderm
    • 1. external, skin, nervous system
    • 2. internal, digestive system, liver, gull bladder, pancreas
    • 3. middle tissue-muscle, circulatory, bone, reproductive
    • -fluid filled space between gut and outer wall , organs move independently of eachother
    • -programmed cell suicide by proteins
Card Set
BIO 32 47 33.txt
review 32 47 33