120 Questions
What is the percentage of sperm deposited in the vagina that enter the cervix?
1%
Where do sperm become less motile and cease their migration?
Isthmus
What is the region of the uterine tube where fertilization usually occurs?
Ampulla
What is the primary function of yellowish luteal cells during the first four months of pregnancy?
Maintaining pregnancy by secreting progesterone
What stimulates sperm motility at ovulation, allowing them to swim to the ampulla?
Chemoattractants produced by cumulus cells
Which component of the placenta takes over progesterone secretion after the fourth month of pregnancy?
Trophoblastic component
How long can sperm remain viable in the female reproductive tract?
Several days
What is the fate of the corpus luteum of pregnancy if it is removed before the fourth month?
It leads to abortion
During which phase of oocyte penetration does the spermatozoon penetrate the oocyte membrane while losing its own plasma membrane?
Phase 3, fusion of sperm and oocyte cell membranes
What is the function of the fimbriae in the female reproductive system?
To collect and sweep the oocyte into the uterine tube
What is the primary cause of the breakdown of collagen fibers surrounding the follicle?
Elevated LH levels
During which stage of oocyte development is the growth independent of FSH?
Growing follicle stage
What is the result of the muscular contractions in the ovarian wall during ovulation?
Extrusion of the oocyte
At what stage of meiosis is the oocyte arrested before ovulation?
Metaphase II
What is the structure that appears at the apex of the ovary during ovulation?
Stigma
What is the primary function of the zona pellucida in the fertilization process?
To facilitate and maintain sperm binding and induce the acrosome reaction
What is the outcome of the contact between the sperm head and the oocyte surface during fertilization?
The release of lysosomal enzymes from cortical granules lining the oocyte plasma membrane
What is the role of the corona radiata in the fertilization process?
To aid the fertilizing sperm in penetrating the barriers protecting the female gamete
What is the purpose of the acrosome reaction during fertilization?
To allow the sperm to penetrate the zona pellucida
What is the outcome of the zona reaction during fertilization?
The prevention of sperm penetration and the inactivation of species-specific receptor sites for spermatozoa on the zona surface
What is the approximate time frame for the fertilized oocyte to reach the uterine lumen?
3-4 days
What happens to the corpus luteum if fertilization does not occur?
It degenerates and forms a corpus albicans
What prevents the degeneration of the corpus luteum if the oocyte is fertilized?
Human chorionic gonadotropin
What is the name of the structure formed by the corpus luteum if the oocyte is fertilized?
Corpus luteum graviditatis
What is the consequence of the decrease in progesterone production if the oocyte is not fertilized?
Menstrual bleeding
What is the primary function of cortical oocyte granules during fertilization?
To release lysosomal enzymes that prevent polyspermy
What is the outcome of the zona reaction during fertilization?
The zona pellucida alters its structure and composition to prevent sperm binding and penetration
During fertilization, what is the fate of the plasma membrane covering the acrosomal head cap?
It disappears during the acrosome reaction
What is the mechanism by which the sperm and oocyte membranes fuse during fertilization?
The interaction of integrins on the sperm and their ligands on the oocyte
What is the immediate response of the oocyte to sperm penetration?
The resumption of the second meiotic division
What is the primary characteristic of the second polar body?
It receives hardly any cytoplasm
What is the term for the process of initial cellular and molecular events associated with early embryogenesis?
Metabolic activation
What is the fate of the tail of the spermatozoon during fertilization?
It detaches and degenerates
What is the process by which the male and female pronuclei come into close contact?
Fusion
What is the consequence if the male and female pronuclei do not replicate their DNA?
Each cell of the two-cell zygote has half the normal amount of DNA
What is the structure formed by the chromosomes during the pronuclear stage?
Vesicular nucleus
What is the term for the stage of development where the male and female pronuclei come into close contact?
Pronuclear stage
What is the significance of the activating factor during fertilization?
It triggers the initial cellular and molecular events associated with early embryogenesis
What is the stage of development that follows immediately after DNA synthesis?
Normal mitotic division
What is the term for the fertilized oocyte?
Zygote
What is the primary mechanism by which sperm move from the cervix to the uterine tube?
Muscular contractions of the uterus and uterine tube
At which stage of fertilization do the male and female pronuclei come into close contact?
During the formation of the zygote
What is the primary function of the cumulus cells surrounding the egg during fertilization?
To produce chemoattractants for sperm
What is the fate of the sperm tail during fertilization?
It is lost during the fertilization process
At what stage of fertilization do the chromosomes become arranged on the spindle and move to opposite poles?
During the second meiotic division of the oocyte
What is the primary function of the inner acrosomal membrane during fertilization?
To dissolve and allow the sperm nucleus to penetrate the oocyte
What is the consequence of the removal of the corpus luteum before the fourth month of pregnancy?
Abortion will occur
During which phase of oocyte penetration does the spermatozoon bind to the zona pellucida?
Phase 1, where the spermatozoon binds to the zona pellucida
What is the role of the trophoblastic component of the placenta during pregnancy?
To produce progesterone to maintain pregnancy
What is the structure that collects the oocyte and sweeps it into the uterine tube during ovulation?
Fimbriae
What is the primary function of prostaglandin levels in response to the LH surge during ovulation?
To cause local muscular contractions in the ovarian wall
What is the outcome of the high concentration of LH during ovulation?
Digestion of collagen fibers surrounding the follicle
What is the stage of meiosis at which the oocyte is arrested before ovulation?
Metaphase II
What is the structure that appears at the apex of the ovary during ovulation?
Stigma
What is the term for the process of initial cellular and molecular events associated with early embryogenesis?
Blastulation
What is the primary mechanism by which the oocyte prevents polyspermy during fertilization?
Release of cortical oocyte granules containing lysosomal enzymes
What is the immediate consequence of the release of cortical oocyte granules during fertilization?
Alteration of the zona pellucida structure and composition
Which part of the spermatozoon fuses with the oocyte membrane during fertilization?
The membrane that covers the posterior region of the sperm head
What is the response of the oocyte immediately after sperm penetration?
Resumption of the second meiotic division
What is the fate of the plasma membrane covering the spermatozoon during fertilization?
It is left behind on the oocyte surface
What is the purpose of the ligand ZP3 in the zona pellucida?
To facilitate and maintain sperm binding and induce the acrosome reaction
What is the result of the permeability change of the zona pellucida during fertilization?
Sperm penetration is prevented
What is the role of capacitated sperm in fertilization?
To aid in the penetration of the corona radiata
What is the function of the cortical granules lining the plasma membrane of the oocyte during fertilization?
To release lysosomal enzymes to prevent sperm penetration
What is the outcome of the interaction between the sperm head and the oocyte surface during fertilization?
Lysosomal enzymes are released from cortical granules
What is the typical composition of the chromosomes in the female pronucleus?
22 plus X
During fertilization, what is the fate of the tail of the spermatozoon?
It degenerates
What happens to the corpus luteum if fertilization occurs?
It continues to grow and forms the corpus luteum of pregnancy
What is the process that occurs immediately after DNA synthesis in the pronuclear stage?
Mitosis
What prevents the degeneration of the corpus luteum if the oocyte is fertilized?
Human chorionic gonadotropin
What is the term for the stage of development where the male and female pronuclei come into close contact and lose their nuclear envelopes?
Pronuclear stage
How long does it take for the fertilized oocyte to reach the uterine lumen?
Approximately 3-4 days
Which structure is formed by the chromosomes during the pronuclear stage?
Vesicular nucleus
What occurs to the granulosa cells after ovulation?
They differentiate into lutein cells
What occurs to the corpus luteum if fertilization does not occur?
It degenerates and forms a corpus albicans
What is the consequence if the male and female pronuclei do not replicate their DNA?
The zygote will have half the normal amount of DNA
What is the significance of the activating factor during fertilization?
It encompasses the initial cellular and molecular events associated with early embryogenesis
During which stage of fertilization do the male and female pronuclei come into close contact?
Pronuclear stage
What is the outcome of DNA synthesis in the pronuclear stage?
The preparation for a normal mitotic division
What is the characteristic of the second polar body?
It receives a small amount of cytoplasm
What is the stage of meiosis at which the oocyte is arrested before ovulation?
Metaphase
What is the result of the high concentration of LH during ovulation?
Increase in collagenase activity
What is the role of prostaglandin levels in response to the LH surge during ovulation?
Causing local muscular contractions in the ovarian wall
What is the structure that breaks free from the ovary during ovulation?
Oocyte and surrounding granulosa cells
What is the process that occurs to the collagen fibers surrounding the follicle during ovulation?
Digestion
What is the primary mechanism by which sperm are propelled through the female reproductive tract?
Muscular contractions of the uterus and uterine tube
At which stage of meiosis is the oocyte arrested before ovulation?
Metaphase of the second meiotic division
What is the approximate region of the uterine tube where fertilization typically occurs?
Ampulla
What is the fate of the sperm heads that do not penetrate the oocyte?
They remain stuck in the zona pellucida
How long can sperm remain viable in the female reproductive tract?
Several days
What is the approximate number of spermatozoa that reach the site of fertilization?
300 to 500
What is the primary function of the zona pellucida?
To facilitate and maintain sperm binding and induce the acrosome reaction
What is the result of the contact between the sperm head and the oocyte surface during fertilization?
Release of lysosomal enzymes from cortical granules
What is the role of the ligand ZP3 in fertilization?
To mediate binding and the acrosome reaction
What is the consequence of the release of lysosomal enzymes from cortical granules during fertilization?
Prevention of sperm penetration and inactivation of species-specific receptor sites
What is the characteristic of the pronuclei during the pronuclear stage?
They are indistinguishable
What happens to the chromosomes after DNA synthesis during the pronuclear stage?
They organize on the spindle
What is the primary function of the yellowish luteal cells in the ovary?
To secrete progesterone
What is the consequence if the male and female pronuclei do not replicate their DNA?
Each cell of the two-cell zygote has half the normal amount of DNA
What is the structure formed by the chromosomes during the pronuclear stage?
Vesicular nucleus
What is the consequence of removing the corpus luteum before the fourth month of pregnancy?
Abortion will occur
During which phase of oocyte penetration does the spermatozoon bind to the zona pellucida?
Phase 2
What is the term for the process of initial cellular and molecular events associated with early embryogenesis?
Metabolic activation
What is the structure that collects the oocyte and sweeps it into the uterine tube during ovulation?
Fimbriae
What is the stage of meiosis at which the oocyte is arrested before ovulation?
Metaphase II
What is the primary mechanism of preventing polyspermy during fertilization?
Cortical and zona reactions
What happens to the spermatozoon's plasma membrane during fertilization?
It is left behind on the oocyte surface
What is the immediate response of the oocyte to sperm penetration?
It releases cortical granules
Which part of the sperm head fuses with the oocyte membrane during fertilization?
The posterior region of the sperm head
What is the result of the release of cortical oocyte granules during fertilization?
The zona pellucida alters its structure and composition
What is the approximate time frame for the fertilized oocyte to reach the uterine lumen?
3 to 4 days
What is the name of the structure formed by the corpus luteum if the oocyte is fertilized?
Corpus luteum graviditatis
What is the consequence of the decrease in progesterone production if the oocyte is not fertilized?
Menstrual bleeding
What is the primary characteristic of the corpus luteum?
It is a yellowish projection on the surface of the ovary
What is the fate of the cavity of the follicle after ovulation?
It becomes a mass of fibrotic scar tissue
What is the primary function of granulosa cells in the corpus luteum?
They produce progesterone
What is the term for the process of degeneration of the corpus luteum?
Luteolysis
What is the approximate time frame for the corpus luteum to reach maximum development after ovulation?
9 days
What is the primary function of luteal cells in the corpus luteum?
They produce progesterone
What is the consequence of the degeneration of the corpus luteum if the oocyte is not fertilized?
Menstrual bleeding
Fertilization. Blastulation. Implantation. Gastrulation. Embryonic disc: ectoderm, endoderm, mesoderm. Differentiation of the embryonic disc layers.
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