58 terms

Test 1- Early Embryonic Development

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Terms in this set (...)

otogenesis
transformation of a zygote into a new individual
phylogenesis
transformation of a simple organism to complex
embryo
developmental stage from time of fertilization to completion of organogenesis
organogenesis
the establishment of the major organ primorida
fetus
developmental stage comprising the remainder of prenatal development after completion of organogenesis, devoted to growth, differentiation and maturation
gametogenesis
differentiation and maturation of primordial germ cells into gametes
endoderm
germ cells for gametogenesis originate from the _______ of the yolk sac
oogonia
primordial germ cells within the female embryonic gonad
birth
oogonia continue mitotic divisions in the ovary until ______ then stop
oogenesis
maturation of primordial germ cells into female gametes
polar body
a small cell containing little cytoplasm that is produced during oogenesis, later discarded
primary oocytes
some oogonia differentiate into ______ that entery meiosis I and remain in resting stage until puberty
resting
at birth only _____ primary oocytes are found in the ovary
meiosis
a reduction division process that produces haploid cells
atresia
many oogonia and primary oocytes undergo ______ (death)
meiosis I- secondary oocyte
ovulatory hormones stimulate the completion of _______ that results in a haploid ________ and a polar body
meiosis II
ovulated secondary oocytes enter the ______ stage of oogenesis
fertilization
completion of meiosis II in females occurs only if _____ occurs
primary oocytes
in the dog and fox _______ are released at ovulation
resting
meiotic errors such as age-related damage to oocytes occur during the ______ stage
degenerate
multinucleated ovarian follicles usually _____
zona pellucida
protective coating directly surrounding the ovarian follicle
corona radiata
The layer of cells that surrounds an ovarian follicle
spermatogenesis
maturation of primordial germ cells into male gametes, a continuous process
puberty
spermatogonia continue mitosis and enter the resting stage of meiosis I until ______
primary spermatocytes
at puberty spermatogonia differentiate into ________
meiosis I
_______ of spermatogenesis may be completed at any time, resulting in two equal haploid secondary spermatocytes
meiosis II- spermatids
secondary spermatocytes complete ______ to create four haploid ______
spermiogenesis
spermatids undergo ________ to become motile spermatozoa
capacitation
physiological changes of spermatozoa in the female genital tract necessary for fertilization
fertilization
fusion of gametes that occurs in the ampulla of the uterine tube
zygote
fertilization creates a _______
zona pellucida
the first step of fertilization is penetration of the _______
fusion
after penetration of the zona pellucida occurs during fertilization there is ______ of the gamete membranes
integration
after fusion occurs during fertilization there is ______ of genetic material
diploid- sex
fertilization restores a ______ chromosome number and determines the ____ of an individual
cleavage
fertilization initiates the process of _______ of the cell
morula
a spherical mass of cells formed by rapid mitotic divisions
zona pellucida
during the morula stage the size of the embryo does not change because the _______ is still present
zona pellucida
prevents adherence to the uterine tube that would lead to ectopic pregnancy and embryo rejection
blastula
a single layer of cells lining a central cavity during cleavage
blastula
the zona pellucida degenerates during the _____ stage of cleavage and implantation follows
trophoblast
the outer single cell cell layer of the blastocyst that forms the fetal membranes
inner cell mass
central core of cells in the blastocyst that forms the embryo
blastomeres
at blastocyst stage _______ have restricted developmental potential
hypoblast
cells of the inner cell mass delaminate and form the ________ surrounding the trophoblast
extraembryonic endoderm- yolk sac
the hypoblast cells become ___________ which eventually goes on to form the ______
epiblast
the cells of the inner cell mass that do not form the hypoblast remain above the hypoblast and form the _______
extra-embryonic
once formed, the epiblast splits to form the _________ epiblast which lines the amniotic cavity
embryonic
once formed, the epiblast splits to form the _________ epiblast which is the source of all three germ layers
primitive streak
the cells on the midline of the epiblast form the ________
endoderm
some cells of the epiblast displace the hypoblast to form the ________
mesoderm
some cells of the epiblast migrate between the epiblast and endoderm to form the ________
ectoderm
the cells of the epiblast that do not migrate and do not form the endoderm or mesoderm become the _________
primitive streak
establishes the longitudinal axis of the embryo, is the master organizer of the mesoderm layer
ectoderm
forms the epidermis and nervous system
mesoderm
forms the cardiovascular system, urinary and genital systems, blood cells, and most connective and muscular tissues
endoderm
forms the digestive and respiratory tracts, urinary bladder, tympanic cavity, and parenchyma of the thyroid and parathyroid glands