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Early Embryogenesis and Maternal Recognition of Pregnancy - Coggle Diagram
Early Embryogenesis and Maternal Recognition of Pregnancy
terms
syngamy: fusion of the male and female pronuclei
after this the zygote becomes an embryo
embryo has not acquired an anatomical form that is readily recognizable in appearance as a member of the specific species
embryo: an organism in the early stages of development
fetus: a potential offsprings that is still within the uterus, but is generally recognizable as a member of a given species
conceptus: product of conception
the embryo during the early embryonic stage
embryo and extraembryonic membranes during the preimplantation stage
the fetus and placenta during the post-attachment phase
four steps the need to happen before the embryo can attach to the uterus
hatching of the blastocyst from the zona pellucida
maternal recognition of pregnancy
Development within the confines of the zona pellucida
formation of the extraembryonic membranes
ootid: when male and female pronuclei can be observed, the cell
one of the largest single cells in the body and is characterized by having an enormous cytoplasmic volume relative to nuclear volume
blasomeres: first cleavage division generates a two celled embryo
totipotent: used to describe the ability of a single cell (blastomere) to give rise to a complete, fully formed individual
morula: when a solid ball of cells is formed and individual blastomeres can no longer be counted accurately, the early embryo
hatching of the blastosyt is governed by three forces
Production of enzymes by the trophoblastic cells
contraction of the blastocyst
growth and fluid accumulation within the blastocyst
development of the extraembryonic membranes represents an "explosion" of embryonic tissue growth prior to attachment
the extraembryonic membranes of the preattachment embryo consist of the
chorion
amnion
yolk sac
allantios
extraembryonic membranes: dramatic growth of the conceptus is due largely to the development of a set of membranes
allantois: fluid-filled sac that collects liquid waste from the embryo
allantochorion: fetal contribution to the placenta and will provide the surface for attachments to the endometrium
in most species, the conceptus must provide a timely biochemical signal or the preganacy will terminate
maternal recognition of pregnancy must occur prior to luteolysis
a successful pregnancy requires maintenance of high blood progesterone concentrations
embryo transfer technology provides avenues for reproductive and genetic enhancement
embryo transfers require set of procedures that allows removal of pre-attachment embryos from the reproductive tract of a donor female and transfers them into the reproductive tract of a recipient female
advantages of embryo transfer are
circumvention of seasonal reproduction
enhanced generation of offspring in monotonous species
assisted reproduction for infertility in humans
enhanced reproductive potential of endangered species
enhanced genetic diversity across a wide geographical region (ship embryos rather than animals)
successful embryo transfer involves
recovery of embryos from the donor
maintenance of viable embryos in vitro
artificial insemination of the donor female
transfer of embryos to recipient females
superovulation (hyperstimulation of the ovaries) of the donor
synchronizing the cycles of donors and reciepients
superovulation results from hyperstimulation of the ovaries with gonadotropins
superovulation: treatment of a female with gonadotropins (typically FSH) to increase the number of oocytes that are selected to become dominant follicles and the ovulate
recovery of oocytes from ovaries can be accomplished by
surgically exposing the ovary and aspirating follicles
non-surgically aspirating follicles utilizing ultrasonography
aspirating follicles postmortem in an abattoir
recovery of embryos from the donor females may be accomplished in several wasy
recovery of embryos from the oviduct requires surgery in all spaces
oocytes can be recovery directly from the ovary using aspiration with a hypodermic needle
embryo viability must be maintained in vitro
in order for embryos to be transferred successfully into recipient females they must be stored in an environment that maintains viability
embryos can be frozen successfully for long term storage
transfer of embryos can be accomplished surgically or non-surgically
zona pellucida is an important component of the early embryo
embryo transfer procedures have become very successful