embry 1 again Flashcards
What is a fetus?
an orgnaism that breathes no air, does not use the digestive tract and lives in a sterile environment
what is a newborn?
an air-breathing organism with a functional GI tract that quickly becomes a colonized by microbial flora
what does the ovaries produce?
oocytes, progesterone and estrogen
what are oocytes?
female haploid gametes
what is another name for the Uterine tube?
fallopian tube
what does the uterine tube receive from the ovaries?
oocytes
where is the site where sperm fertilizes the oocyte?
Uterine tube
Where is the site where the embryo develops
uterus
where is the site where the placenta and membranes develop
uterus
what is a placenta?
site where the maternal and embryonic vasculatures exchange substances
what does unique mean
crossing-over between maternal and paternal chromatids during prophase I to end up with “mixed” chromatids
what does “mixed” mean
some paternal, some maternal genes
where does fertilization occur?
in the ampulla of the uterine tube
what does ovulation mean?
release of a secondary oocyte from ovarian follicle
the ovulated secondary oocyte together with zona pellucida, is externally covered with what
cumulus oophorus
cumulus oophorus will rearrange and form what?
corona radiata
what happens when the zona pellucida is penetrated by a sperm cell and “injects” its genetic material?
it becomes impenetrable and other sperm cells cannot penetrate
what are cells that surround the oocyte, found outside of the zona pellucida?
corona radiata
what are gametes?
a haploid germ cell
what are sperm?
gamete from testes
what are oocytes?
gamete from ovaries
what is fertilization?
fusion of the pronucleus of the 2 gametes
what is the zona pellucida?
protein coat that surrounds an oocyte as well as the early embryo
what is a zygote?
a fertilized, diploid oocyte, has not yet divided
what is an embryo?
multicellular organism, prior to fetal stage (period from fertilization - end of week 7)
what is a fetus?
multicellular organism, from end of embryonic stage to birth
what is a neonate?
newborn
what is extraembryonic
cells from during development that do not become part of the neonatal organism, but involute or contribute to the fetal membranes
what is morula?
approximately 16-cell stage (12-32 cells) of an embryo, no blastocoel
what is blastocyst?
a spherical mass of cells that is composed of a trophoblast that surrounds a fluid cavity (blastocoel) and an inner cell mass (embryoblast)
what is cleavage?
cell division in the early embryo -> each division does not increase the size of the embryo, instead each division results in a smaller and smaller cells
what is a blastomere
a cell that is totipotential and is present during very early develop, product of cleavage
what does totipotential mean
a cell that can become any cell
what does implantation mean?
occurs when an embryo contacts and then becomes surrounded by the endometrium of the uterus
what is a trophoblast
layer of cells on the outside of the sphere (blastomere)
what are embryoblast (inner cell mass)
surrounded by the trophoblast, these cells develop into the embryo
what is blastocoel?
the fluid filled cavity within the sphere