M1: Parturition Phase I Flashcards
The average is cycle is ______ with a range of ________.
28 days. 25-32 days.
The development of predictable, regular, cyclical and spontaneous ovulatory menstrual cycle is regulated by the complex interactions of the
Hypothalamic-pituitary axis, Ovaries & Genital tract “HOG”
Released by the hypothalamus. Initiates the menstrual cycle. Transmitted from the hypothalamus to anterior pituitary gland. It signals the gland begin producing two hormones; ____ & ___.
GnRH. FSH & LH.
Active early in the cycle. Responsible for maturation of the ovum. Under the influence of this, the ovary begins to produce estrogen and the endometrium begins to proliferate.
FSH
A hormone that becomes most active at midpoint of the cycle. Responsible for ovulation or release of the mature egg cell from the ovary and growth of the uterine lining during the second half of the menstrual cycle. Aids in the formation of progesterone in the corpus luteum.
LH
Two members of the transforming growth factor-family. These two are triggers of the follicular development. FSH only enhances.
Growth differentiation factor 9 (GDF9) & Bone Morphogenetic protein 15 (BMP15)
Follicular development: FSH rise leading to follicle development is called
Selection window of the ovarian cycle
Follicular development: rise in parallel to growth of a dominant follicle and the increase in its number of granulosa cells (exclusive site of FSH receptor expression)
Estrogen
Small rise in the number signals ovulation. It maintains the pregnancy.
Progesterone
The increase in circulating ______ during the late luteal phase of the previous cycle stimulates an increase in FSH receptors and subsequently, the ability of ___________ to convert androstenedione to __________.
FSH. Cytochrome P450 aromatase. Estradiol.
The requirement of thecal cells which respond to LH & granulosa cells which responds to FSH, represents the ____________ for estrogen synthesis.
Two-gonadotropin, two-cell hypothesis
Conversion of androstenedione to estradiol
Theca cells
Progesterone positive feedback on pituitary leads to LH release. Inhibin negative feedback on pituitary to inhibit FSH.
Granulosa cells
The onset of the gonadotropin surge resulting from increasing estrogen secretion by preovulatory follicles is a relatively precise predictor of ovulation. It occurs ________ before the release of the ovum.
Ovulation. 34-36 hours.
Induces remodeling of the ECM to allow release of the mature oocyte with surrounding cumulus cells through the surface epithelium
LH
34-36hrs before release of the ovum from the follicle
Estrogen surge
Peaks at 10-12hrs before ovulation and stimulates the resumption of meiosis in the ovum with the release of the first polar body.
LH secretion
Post ovulation. Neovascularization. VEGF. Hypertrophy and increase capacity to synthesize hormones. Estrogen decreases with a secondary rise at the midluteal phase. Toward the end of this phase, there is secondary decrease in estradiol production.
Luteal or Postovulatory Phase
Granulosa lutein cells
Progesterone
________ develops from the remains of the dominant/graafian follicle in a process called _________. Rapidly regresses _______ days.
Corpus Luteum. Luteinization. 9-11.
Loss of luteal cells by apoptotic cell death. Decrease circulating estradiol and progesterone levels which are critical to allow the follicular develolment and ovulation during the next ovarian cycle.
Luteolysis
Correspond to follicular phase of the ovarian cycle. Increase estradiol. Re epitheliazation and angiogenesis. Glandular hyperplasia and increased stromal ground substance. Characterized by proliferation of vascular endothelial, stromal & glandular cells.
Proliferative/Preovulatory Endometrial Phase
Narrow & Tubular
Early proliferative
Endometrium thickens from bot glandular hyperplasia and increased stromal ground substance. Loss of stroma and the glands of the functionalis layer is widely spread.
Late proliferative
Determining the menstrual cycle day by endometrial histological criteria but is difficult during proliferative phase because of the considerable variation of phase length among women.
Dating
Correspond to luteal phase of the ovarian cycle. 12-14 days. Endometrial dating. Glandular epithelium histology. Window of implantation seem on days _______. Increase vascularization of spiral arteries.
Secretory or Postovulatory Endometrial Phase
Important in preparation of blastocyst implantation
Pinopodes
Between days _______ is striking changes associated with predecidual transformation of the 2/3 of the ________.
22-25. Functionalis layer.
Primarily secretes progesterone which is important to maintain pregnancy
Corpus Luteum
Life span of the egg
24hrs
Lifespan of the sperm
72hrs
Site of fertilization
Fallopian tube
Must be present in the fallopian tube at the time of the oocyte arrival
Spermatozoa
Still within the fallopian tube. Diploid 46 chromosomes. Surrounded by a thick zona pellucida. Forms the blastomeres, contain the polar body that are non functional and will soon regenerate.
Zygote(2/4/8 cell stage)
A solid mulberry like balls of cells. Enters the uterine cavity about 3 days after fertilization. Ends when the blastocyst forms.
Morula (16 cell stage
Gradual accumulation of fluid between the cells of the morula forms the early blastocyst. Consists of a single layer of ectoderm. 50-60 blastomeres present. Should be near the uterine cavity. Contains the inner cell mass, the cavity and the cells that will form into ______. The outer cells are called ________.
Blastocyst. Trophoblast. Trophectoderm.
Normally once fertilized, the _____ moves down the fallopian tube towards the uterus, growing in size and complexity to form the _______. (From which the embryo and placenta will develop)
Ovum. Blastocyst.
Within the days of conception, the blastocyst attaches itself to the lining of the
Upper part of the uterus
If the passage of the fertilized ovum along the fallopian tube is delayed, then the blastocyst is ready for attachment before it has reached the uterine cavity, this will lead to
Tubal pregnancy
Anything that affects the passage of the blastocyst along the fallopian tube may thus increase the likelihood of an
Ectopic pregnancy
Produces proteases that degrades selected endometrial ECM proteins to allow its invasion
Trophoblast
Trophoblast should implant at the
Posterior upper part of the endometrium
If implanted at the bottom (near the internal cervical os) could result to
Placenta previa
Blastocyst Implantation: ______ after fertilization, the embryo implants at the uterine wall.
6-7days
Blastocyst Implantation: successful implantation requires a receptive endometrium appropriately primed with estrogen and progesterone by
Corpus luteum
Blastocyst Implantation: uterine receptivity is limited to days ______ of the cycle.
20-24
Blastocyst Implantation: if blastocyst approaches the endometrium after day 24, the potential for adhesion is diminished due to ____________ synthesis prevents receptors.
Antiadhesive glycoprotein
Blastocyst Implantation: expressed on endometrial epithelium are considered a receptivity markers for blastocyst attachment
Alpha V beta 3 & Alpha 4 beta 1 Integrins
Initial contact of the blastocyst to the uterine wall (upper portion of the uterine wall)
Aposition
Increased physical contact between the blastocyst and uterine epithelium
Adhesion
Penetration and invasion of the syncythiotropoblast and cytotroblast into the endometrium, inner third of the myometrium.
Invasion
Successful endometrial blastocyst adhesion involves modification in expression of
Cellular Adhesion Molecules (CAMs)
Cell surface receptors that mediate adhesion of cells to ECM proteins
Integrins
Expressed on endometrial epithelium are considered a marker of receptivity for blastocyst attachment
V3 & 41 Integrins
Exhibits the most variable structure, function and development pattern of all placental components.
Trophoblasts
Human placental formation begins in the _________, which appears in the ______ stage. Gives rise to the ________ cell layer encircling the blastocyst.
Trophodectoderm. Morula. Trophoblast.
Early of Trophoblast Invasion: By ____ day the blastocyst becomes totally encased within the ________.
10th. Endometrium.
Early of Trophoblast Invasion: At ______ of development, the blastocyst wall facing the uterine lumen is single layer of flattened cells.
9 days
A specialized, highly modified endometrium of pregnancy. It is essential for hemochorial placentation, that is, one in which maternal blood contacts trophoblasts.
Decidualization
Transformation of secretory endometrium to decidua, is dependent on estrogen and progesterone and factors secreted by the implanting blastocyst.
Decidualization
Directly beneath the site of blastocyst implantation
Decidua basalis
Overlying the enlarging blastocyst and initially separating it from the rest of the uterine cavity
Decidua capsularis
Lines the rest of the uterus.
Decidua parietalis
During early pregnancy, there is a space between the decidua capsularis & parietalis because the _________ does not fill the entire uterine cavity. By _______ weeks gestation, the expanding sac has enlarged to completely fill the uterine cavity. The resulting apposition of the decidua capsularis & parietalis creates the _________ and the uterine cavity is functionally obliterated.
Gestational sac. 14-16weeks. Decidua vera.
The decidua parietalis & basal are composed of three layers
Zona compacta, spongiosa & basalis.
Surface or compact zone
Zona compacta
Middle portion or spongy zone with remnants of glands and numerous small blood vessels
Zona spongiosa
Basal zone
Zona basalis
The zona compacta & spongiosa together form the _________. The ______ remains after delivery and gives rise to new endometrium.
Zona functionalis. Basal zone.
Completed only with blastocyst implantation. Decidual cell becomes surrounded by a pericellular membrane. Allow attachment of _________. Protection against selected cytotrophoblastic proteases. Placenta accreta.
Decidual reaction. Cytotrophoblasts.
Is a zone of fibrinoid degeneration in which invading trophoblasts meet the decidua
Nitabuch layer
Blood supply to the ________ is lost as the embryo/fetus grows. Blood supply to the ________ through spiral arteries persists, retain a smooth muscle wall and endothelium and thereby remain responsive to vasoactive agents.
Decidua capsularis. Decidua parietalis.
The spiral arterioles are invaded by the cytotrophoblast destroying its walls leaving only a shell without smooth muscles or endothelial cells so they cannot react to vasoactive agents
Decidua basalis
Transport blood between the placenta and the fetus contain smooth muscles that can react to vasoactive agent
Fetal chronic vessel
A product of the same gene that encodes for anterior pituitary prolactin.
Decidual prolactin
Is the source of prolactin that is present in enormous amounts in amniotic fluid. Not to be confused with placental lactogen (hPL) which is produced only by _________.
Decidua. Syncytiotrophoblasts.
The protein preferentially enters _________ and little enters the maternal blood. Consequently, prolactin levels in amniotic fluid are extraordinarily high and may reach 10,000 ng/mL during weeks _______. _______ function between maternal and fetal tissues.
Amnionic fluid. 20-24. Paracrine.
Maintenance of amniotic fluid volume. Because most or all decidual prolactin enters amnionic fluid inside gestational sac.
Decidual prolactin
Increase fluid inside gestational sac
Polyhydramnios
Decrease fluid in gestational sac
Oligohydramnios
Decidual prolactin may act in regulating ___________ during pregnancy. Prolactin receptors in a number of bone marrow derived immune cells, and prolactin may stimulate _______ in an autocrine or paracrine manner.
Immunological functions. T cells.
May play a role in regulation of angiogenesis during implantation
Prolactin
Enhances angiogenesis whereas the proteolytic fragment can inhibit new vessel growth
Protein
Decidual prolactin has been to have a protective function by repressing expression of ______ detrimental to pregnancy maintenance.
Genes
Acts synergistically with cyclic adenosine monophosphate on endometrial stromal cells in culture to increase prolactin expression
Progestins
Attenuates the rate of decidual prolactin secretion
Arachidonic acid
Decrease decidual prolactin secretion
Cytokines & EGF
First day of menstrual period
LMP
