BIO Chapter 47

  1. Cleavage
    early, rapid cell division without growth that creates a hollow ball of cells (blastula)
  2. Gastrulation
    • cells rearranged into 3-layered gastrula
    • layers now in the ball of cells
  3. Organogenesis
    layers interact and give rise to organs
  4. Acrosomes
    hydraulic enzymes (enzymes that break things down with water)
  5. Fertilization envelope
    • develops once sperm gets inside an egg
    • then the whole chemical balance of the egg has been changed by the sperm (this is the reason only the first sperm can fertilize an egg)
  6. Proteins in sperm
    match up with the receptor of the egg
  7. Why is there no growth in cleavages?
    The cells divide so fast (as soon as they can), they basically skip G1
  8. Vegetal pole
    contains lots of yolk
  9. Animal poles
    contains little yolk
  10. Gastrulation
    • rearranges the cells of a blastula into a 3-layered embryo, called a gastrula, which has a primitive gut
    • goal: to give actual layers that wrap around each other; mass movement of cells
  11. Layers of gastrulation
    • Ectoderm
    • Mesoderm
    • Endoderm
  12. Ectoderm
    outer layer (skin, sweat glands, hair follicles, tooth enamel, etc.)
  13. Mesoderm
    middle layer (skeletal, muscular, and reproductive systems, etc.)
  14. Endoderm
    inner layer (liver, pancreas, linings of reproductive system, urethra, digestive system, etc.)
  15. Two general principles of the developmental fate of cells
    • During early cleavage divisions, embryonic cells must become different from one another
    • After cell asymmetries are set up, interactions among embryonic cells influence their fate
  16. 3 axes
    • Proximal-distal axis
    • Anterior-posterior axis
    • Dorsal-ventral axis
Card Set
BIO Chapter 47
Chapter 47: Animal Development