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2015-09-05 11:30:07
vetmed reproduction embryogenesis

vetmed reproductive system
Show Answers:

  1. What is syngamy?
    when the 2 pronuclei in the fertilized ootid fuse
  2. What defines a morula?
    more than 16 blastomeres
  3. When a morula becomes the early blastocyst...
    the blastomeres fuse and go to the periphery to either become part of the ICM or trophoblast
  4. What is the ICM?
    pluripotent group of cells that become the embryo proper
  5. What is the trophoblast?
    cells that line the blastocyst that become the placenta
  6. In the hatching blastocyst, there is...
    rupture of the zona pellucida
  7. The embryo develops in the fallopian tubes for some time; by the time it reaches the uterus, it is in the __________ stage.
  8. What are the 4 pre-attachment events that are requires to establish a pregnancy?
    development of embryo within zona pellucia, hatching of the blastocyst from the zona pellucida, maternal recognition of pregnancy, development of extra-embryonic membranes to form the placenta
  9. As fluid accumulates, the outer cells become flattened around the embryo to form the _________ and the inner cells __________ to form the _________.
    trophoblast; polarize; ICM
  10. What are the extra-embryonic membranes?
    yolk sac, chorion, amnion, allantois
  11. Unlike humans, implantation in domestic animals is _______.
    very long
  12. The yolk sac is formed by the __________.
    primitive endoderm
  13. The chorion and amnion are formed by the _________.
    trophectoderm and mesoderm (both are components of both)
  14. The reproductive system forms from the ___________.
  15. In a cow, if pregnancy has not occurred, __________ declines, causing _________ to increase; _________ binds receptors, stimulating ________ release from the _________ and _________.
    progesterone; oxytocin receptors; oxytocin; PGF2alpha; endometrium; luteolysis
  16. The signal for maternal recognition of pregnancy in cows is _________, which is released from the ___________; it binds to the _________ and inhibits...
    intereferon-tau; hatched blastocyst; endometrium; synthesis of oxytocin receptors----> inhibition of PGF2alpha synthesis
  17. In ruminants, luteolysis is a _______ effect; therefore, when performing ET, you must...
    local; put the embryo on the side with the CL.
  18. What is necessary for maternal recognition of pregnancy in a sow?
    4 embryos, 2 on each side
  19. The signal for maternal recognition of pregnancy in a sow is ________ from the_______, which results in...
    estrogen; conceptuses; PGF2alpha re-reouting from endocrine to exocrine secretion.
  20. In a sow, when pregnancy has not occurred, ...
    PGF2alpha enters circulation to reach the ovaries, causing luteolysis (in pregnancy, estrogen is produced, which re-routes PGF2alpha to the uterine lumen to be inactivated)
  21. Describe fixation in horses.
    pregnancy occurs and progesterone causes uterine tone; embryo moves constantly and freely within the uterus until it gets to big to enter the horns--> gets trapped in the uterine body