Embryoblast cells.
They regulate folliculogenesis in the ovary and the proliferative phase in the uterine endometrium.
Stimulates development of secondary sex characteristics, growth of testes, maturation of seminiferous tubules, and commencement of spermatogenesis.
Human chorionic gonadotropin (hCG).
On about day 13 or 14.
Monthly cycles in the secretion of hypothalamic, pituitary, and ovarian hormones.
Some cease to develop and eventually degenerate.
Only if the cell is fertilized.
Mature vesicular follicle or mature Graafian follicle.
Begins on about day 5 and is complete by day 14.
The embryo proper and its associated extraembryonic membranes, including part of the placenta.
A small, nipple-shaped protrusion formed by the thinning of the follicle wall.
Ectopic pregnancy.
E-cadherin.
The oogonium.
Four spermatids.
Theca externa and membrana granulosa.
It pumps sodium into the interior, causing water to follow through osmosis.
They form in the ovaries and enter the first meiotic prophase, becoming dormant.
A thin layer of acellular material secreted by follicle cells and the oocyte, forming a barrier.
Cells that arise from dormant PGCs and are located under the basement membrane of seminiferous tubules.
The corpus luteum normally degenerates after about 13 days.
The condensed nucleus and an acrosome filled with hydrolytic enzymes.
28 days.
Two secondary spermatocytes.
The combination of sex chromosomes: XY for males and XX for females.
Gonadotropin-releasing hormone (GnRH).
Blastomeres.
The response of endometrial stroma cells differentiating into decidual cells upon blastocyst presence.
An ovulatory surge in FSH and LH.
It stimulates the uterine endometrial layer to thicken and form convoluted glands and increased vasculature.
The trophoblast.
It is scraped off the surface of the ovary by the fimbriated mouth of the oviduct.
The corpus luteum, which is an endocrine structure.
In males, PGCs remain dormant until puberty, while in females, PGCs undergo mitotic divisions and begin meiosis by the fifth month of fetal development.
Female and male pronuclei.
Methotrexate, which blocks rapid division.
The final step that involves changes in the acrosome to prepare for enzyme release to penetrate the zona pellucida.
Estrogens and progesterone.
It shrinks dramatically.
A primary oocyte enclosed by a single-layered squamous capsule of epithelial follicle cells.
It gives rise to the embryo proper and is also called the embryoblast.
They pass through both meiotic divisions, producing secondary spermatocytes and then spermatids.
Two sequential divisions, known as meiosis I and II.
About 74 days.
Crossing over.
The monthly surge of pituitary gonadotropic hormones starting at puberty.
It is where sperm survive and retain their capacity to fertilize an oocyte for 1 to 3 days.
Within the female genital tract, requiring contact with oviduct secretions.
It degenerates after about 14 days and becomes the corpus albicans.
The secretion of histamine and prostaglandins.
Progesterone secreted by the corpus luteum.
The membrane of the swollen germinal vesicle breaks down.
It begins to absorb fluid and develops a fluid-filled cavity, transforming into a blastocyst.
It contains mitochondria that generate energy for swimming.
The spermatogonium.
Because blood vessels at the abnormal site can rupture due to the growth of the embryo and placenta.
Menstruation, the shedding of the degenerated uterine endometrium.
The number of copies of each unique double-stranded DNA molecule in the nucleus.
The follicular epithelium thickens, converting them into primary follicles.
Morula.
The follicle becomes more vascularized and forms a bulge on the surface of the ovary.
One massive haploid definitive oocyte and typically one polar body.
Second meiotic metaphase.
They are connected to maturing spermatocytes and spermatids, facilitating their differentiation.
Increases genetic variability of future gametes.
The number of chromosomes is halved, resulting in cells with 23 chromosomes.
A definitive oocyte and a polar body.
Drug or surgical intervention to interrupt the pregnancy.
They degenerate (undergo atresia).
Testosterone.
Mature gametes.
They provide a mechanism for transferring excess cytoplasm to Sertoli cells.
About 7 million by 5 months of fetal life.
It differentiates into two layers: theca interna and theca externa.
The process of sperm cell differentiation as spermatids mature into sperm.
The acrosome releases enzymes that allow the sperm to penetrate the zona pellucida.
Chiasma.
No DNA replication occurs.
The process that converts primordial germ cells (PGCs) into mature male and female gametes (spermatozoa and definitive oocytes).
It exposes sperm-specific proteins that bind to egg-specific receptors.
The number of copies of each type of chromosome present in a cell nucleus.
It contributes to the secretion of an abundant extracellular matrix, causing the cumulus cell mass to expand several-fold.
It may play a role in regulating meiotic progress and ovulation.
A diploid (2n), 2C cell replicates its DNA and undergoes a single division to yield two diploid, 2C daughter cells.
Spermiation.
The sloughing of the thickened endometrium along with blood and the unfertilized oocyte.
The onset of menstruation and the beginning of the menstrual cycle after puberty.
In the lower part of the epididymis.
As many as 300 million.
Centromere.
A secondary oocyte and a first polar body.
IZUMO1 (sperm-specific) and JUNO (egg-specific).
The blastocyst cavity (blastocoel).
Cleavage.
It hatches from the zona pellucida.
The large, watery nucleus of a dormant primary oocyte that protects its DNA during meiotic arrest.
Progesterone.
To help establish a blood-testis barrier.
The replication of each chromosomal DNA molecule during meiosis I.
It surrounds the oocyte and contains a sperm receptor molecule called ZP2.
Steroid hormones.
They enter a state of dormancy and remain in meiotic arrest.
Increased vascularity and other supportive changes.
Abdominal pain and/or vaginal bleeding.
The random inactivation of one X chromosome in each cell.
The second meiotic metaphase before replication of the centromeres.
They lose their cell-to-cell connections and disaggregate.
Cumulus oophorus.
Diploid (2n).
No, it remains the same size and is enclosed in the zona pellucida.
Follicles become progressively more sensitive to FSH as they advance in development.
A system of seminiferous tubules.
Primary follicles that proliferate to form a multilayered capsule of follicle cells around the oocyte.
Four identical spermatozoa.
Follicles that develop a central fluid-filled cavity called the antrum in response to rising levels of FSH.
Head, midpiece, and tail.
Through a combination of tension from smooth muscle cells and the release of collagen-degrading enzymes.
They become hypermobile and ascend toward the ampulla of the oviduct.
It plays an essential role in fertilization.
Up to 24 hours before losing its capacity to be fertilized.
The cell membranes of the sperm and oocyte fuse.
Capacitation.
Haploid (1n) but 2C.
They differentiate into spermatogonia and undergo successive waves of meiosis to mature into spermatozoa.
X and Y chromosomes.
It helps transport and regulate the exchange of metabolites between the morula and the maternal environment.
Cohesion.
A large definitive oocyte and a diminutive polar body.
The oocyte resumes meiosis and completes the second meiotic division.
Cleavage subdivides the zygote without increasing its size.
It alters sperm receptor molecules to prevent polyspermy.
Diploid (2n) complement of chromosomes and a 2C quantity of DNA.
Formation of a calcium wave and release of cortical granules.
They quickly disappear as chromosomes are replicated.
