All of the following are directly involved with
the implantation process except:
Decidual reaction.
Progesterone.
Epiblast.
Invasion.
Epiblast
Decidual reaction of the endometrium creates a nourishing enviroment for the conceptus as it buries itself by invasion of the uterine endometrial wall.
Progesterone produced by corpus luteum stimulates glandular secretion in the endometrium during the secretory phase of menstruation.
The seven-day blastocyst:
Has a single layer of trophoblast at the embryonic pole.
Has an amniotic cavity.
Is attached to the endometrial epithelium.
Is surrounded by degenerated zona pellucida.
Is called hypoblast.
Is attached to the endometrial epithelium
When does the amniotic cavity form?
2nd week
In what day does the implantation begin?
6th day
As implantation begin, trophoblast divides into what?
syncytiotrophoblast
cytotrophoblast
The inner mass cell divides into what?
Epiblast
Hypoblast
Which of the following are classified as
gonadotropin hormones?
FSH.
GnRH.
Estradiol or estrogen.
Progesterone.
LH
FSH ( follicle development)
LH ( ovulation)
Gonadotropin-releasing hormone is synthesized where? And acts on what?
synthesis: hypothalamus
Action : ant pit
Haploid nuclei that fuse at fertilization are
called:
Homunculi.
Mitotic figures.
Centrioles.
Nucleoli.
Pronuclei.
Pronuclei
The first week of human development is
characterized by the formation of the:
Inner cell mass.
Hypoblast.
Trophoblast.
Blastocyst.
Blastocyst cavity
Syncytiotrophoblast&cytotrophoblast
Inner cell mass.
Hypoblast.
Trophoblast.
Blastocyst.
Blastocyst cavity
Syncytiotrophoblast&cytotrophoblast
During follicular phase of the menstrual cycle:
FSH binds to corpus luteum and stimulates
estrogen production.
FSH binds to granulosa cells of the follicle and stimulates estrogen production.
FSH binds to corpus luteum and stimulates
progesterone production.
FSH binds to granulosa cells of the follicle and stimulates LH production.
The LH surge, caused by increased estrogen, stimulates ovulation after which corpus luteum produces progesterone
FSH binds to granulosa cells of the follicle and stimulates estrogen production.
The LH surge, caused by increased estrogen, stimulates ovulation after which corpus luteum produces progesterone.
Gonadotropin-releasing hormone or GnRH:
Acts on the hypothalamus, causing release of FSH and LH.
Is released once a month from the corpus luteum.
Acts on the anterior pituitary gland, causing
release of FSH and LH
Acts on the anterior pituitary gland, causing
release of progesterone and estrogen
Is one of those meaningless substances that
scientists play with in lieu of working for a living.
Acts on the anterior pituitary gland , causing release of FSH and LH
The LH surge:
Results in ovulation.
Triggers resumption of meiosis within the oocyte.
Is caused by a positive feedback effect of the estrogen.
Results in ovulation
Triggers resumption of meiosis within the oocyte
Is caused by a positive feedback effect of estrogen.
The luteal/progestational/secretory phase of the
menstrual cycle is characterized by:
High circulating levels of FSH and LH.
High circulating levels of progesterone.
An extreme variation in length from cycle to
cycle.
A thin, non-vascularized
epithelium
Thick endometrial lining
High circulatinh levels of progesterone
Thick endometrial lining
The second polar body:
Is released upon stimulation of the follicle by FSH.
Is released as a result of the LH surge.
Is released after fertilization.
Is released after pronuclear formation.
Is also known as the sowth pole.
Is released after fertilization.
The corpus luteum:
Is only functional during the follicular phase of the menstrual cycle.
Has receptors for progesterone and estrogen.
Is rescued from decline by hCG secreted by the implanting embryo.
Produces both FSH and LH.
Corpus luteum is mantained as corpus luteum of pregnancy which secretes progesterone and estrogen.
Is rescued from decline by HCG secreted bythe implanting embryo.
Corpus luteum is mantained as corpus luteum of pregnancy which secretes progesterone and estrogen.
During implantation, the blastocyst:
Implants in the endometrium.
Usually attaches to endometrial epithelium at its embryonic pole.
Usually implants in the posterior wall of the
body of the uterus.
Causes change in the endometrial tissues.
Implants in the endometrium.
Usually implants in the posterior wall of the body of uterus
Usually attaches to endometrial epithelium at its embryonic pole.
Causes change in the endometrial tissues
IMPLANTATION OCCURS WHEN THE TROPHOBLAST CELLS AT THE EMBRYONIC POLE SECRETE PROTEOLYTIC ENZYMES THAT ALLOW THE BLASTOCYST TO PENETRATE THE WALL OF THE UTERUS,
Capacitation of the sperm:
Is caused by zona pellucida.
Occurs in the male.
Prevents polyspermy.
Occurs within the female genital tract.
Is essential for fertilization.
Removes head of the sperm.
Exposes the acrosome.
Occurs within the female genital tract
Is essential for fertilization
Exposes the acrosome
Capacitation involves removing the glycoprotein coat and the seminal plasma proteins from the head of the sperm.
The most significant factors in sperm transport to the vicinity of the oocyte is:
Sperm flagellum (tail).
Vaginal cilia.
An intact zona pellucida.
Smooth muscle contractions.
Gravity.
Oviductal cilia
Smooth muscle contrations
Oviductal cilia
The early stages of cleavage are characterized by:
Formation of a hollow ball of cells.
Formaton of zona pellucida.
Increase in size of the cells of the zygote.
Increase in number of the
cells of tha zygote
Increase in size
Increase in the number of the cells of the zygote
The most common site for implantation in ectopic pregnancy is:
Internal os of the uterus.
Mesentery.
Ovary.
Uterine tube.
Other.
Uterine tube
During the morula stage:
Tight junctions appear between peripheral cells, isolating the inner cells from uterine fluid.
The location of the cells dictates their fate.
The outer cells pump fluid, creating a
fluid-filled blastocoele.
Attachment to the uterine epithelium has not yet occurred.
Tight junctions appear between peripheral cells, isolating the inner cells from uterine fluid.
The location of the cells dectates their fate.
The outer cells oump fluid , creating a fluid-filled blastocoele
Attachment to the uterine epithelium has not yet occured.
Capacitation of the spermatozoa is an activation process that involves changes in the surface coat and plasma membrane over the:
Tail.
Body.
Neck.
Acrosome.
Nucleus.
Acrosome
Implantation will not take place unless the zona _____ is lost.
Pellucida.
Limitans.
Orbicularis.
Corona.
Oophorus.
Pellucida
When does zona pellucida desappears?
day 4
The results of fertilization include the
determination of chromosomal sex, initiation of cleavage and restoration of the diploid number of chromosome.
True.
False.
True
What are the results of fertilization? (3)
Determination of chromosomal sex
Iniation of cleavage
Restoration of diploid number of chromosome
Before a spermatozoan can fertilize an ovum:
The cell membrane is removed from the spermatozoan head.
The zona pellucida must be shed.
The acrosomal membrane must be perforated.
The tailpiece is lost.
The decidua reaction must occur.
The acrosome membrane must be perforated
The decidua reaction occurs only AFTERA fertilization.
At fertilization:
The haploid number of chromosomes is restored.
The chromosomal sex is determined.
Cleavage is inhibited.
The inner cell mass becomes recognizable.
Initiation of cleavage occurs.
The ovum becomes the blastocyst.
The diploid number of chromosomes is restored.
The chromosomal sex is determined.
Initiation of cleavage occurs
The diploid number of chromosomes is restored.
Which of the following events are directly
related to implantation?
Interaction between uterine epithelium and
hypoblast.
Release of protelytic enzymes.
Loss of decidua.
Acrosome reaction.
Capacitation
Loss of zona pellucida
Release of proteolytic enzymes
Loss of zona pellucida
In ectopic pregnancy:
The placenta overbridges the internal os of the uterus.
Implantation is inside the uterus.
Severe bleeding is present during vaginal
delivery.
The most common site is the uterine tube.
the most common site is the uterine tube (oviduct).
Placenta previa : when the placenta overbridges the internal os of the uterus AND causes severe bleeding during vaginal delivery.
Aproximately of many million sperm are there in the average ejaculate of 3.5 cc?
5.
10.
50.
100.
more than 200.
More than 200
The meeting and union of human sex cells is
believed to occur in the:
Upper third of the oviduct.
Middle third of the oviduct.
Lower third of the oviduct.
Uterus.
Cervix.
Ampullary region
Upper third of the oviduct = ampullary region
How are the sperm transported to the ampullary region?
Muscular contractions
Cilia of oviduct
Sexuality is established at the time of:
Ovulation.
Gametogenesis.
Histogenesis.
Morphogenesis.
Fertilization
Fertlization
Cleavage divisions are always:
Meiotic.
Mitotic.
Amniotic.
Anucleotic.
By binary fission.
Mitotic
At which of the following stages of development
is division of embryonic material likely to result in normal monozygotic
twinning?
2-cell stage.
Morula.
Blastocyst.
Implanting embryo.
Bilaminar germ disc
2-cell stage
Morula
Blastocyst
Implanting embryo
Bilaminar germ disc.
With the light microscope, the zona pellucida
appears as a translucent membrane surrounding the:
Primary oocyte.
Zygote.
Morula.
Very early blastocyst.
Primary oocyte
Zygote
Morula
Very early blastocyst
The zona pellucida persists until early in the blastocyst stage.
It dissolves during the blastocyst stage in order to implantation to occur
The fifth day of human development is
characterized by embryonic cells of the:
Inner cell mass.
Embryonic hypoblast.
Epiblast.
Primitive streak.
Amnion.
Inner cell mass
Primitive streak does not form until 3rd week.
inner cell mass= embryoblast
The ______ is/are part of the 4-day embryo.
Syncytiotrophoblast.
Blastocyst cavity.
Notochord.
Somitomeres.
Blastocyst cavity
It is approximately correct to compute the age of the embryo from the fourteenth day after the:
Onset of last menstruation.
Last sexual intercourse.
Last full moon.
Last missed menstrual cycle.
Onset of breast changes.
Onset of last menstruation
As the conceptus begins to sink into the uterine lining, it is characterized by a central cavity surrounded for the most part by
a single layer of cells. At this stage for conceptus is called:
Zygote.
Morula.
Blastocyst.
Trophoblast.
Syncytiotrophoblast.
Cytotrophoblast.
Blastocele.
Inner cell mass.
Blastomere.
Embryoblast.
Zonna pellucida.
Blastocyst
The blastocyst cavity/blastocoele forms within the morula transforming it into blastocyst.
The trophoblast is the single layer of cells surrounding the blastocoele.
