Female and Reproductive Physiology Flashcards by Kringkring B

Approximately 28 days

Ovarian cycle

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Ovarian cycle (PHASES)

Follicular (Preovulatory) Phase

Ovulation

Luteal (Postovulatory) Phase

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Endometrial cycle (PHASES)

Proliferative phase

Secreetory phase

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The functional unit of the ovary

Ovarian follicle

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OOCYTES

Fetal period: 6-7 million oocytes

At birth: 1-2 million oocytes

Onset if puberty: 400,000 oocytes

400 oocytes will ovulate: 99% will become atretic

Eggs ovulated in a lifetime - 500

Depleted at a rate of 1000/month

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2 important cells

Granulosa cells - with the FSH receptors

Theca cells - with the LH receptors

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Formed by 5th fetal month

Started their first meiotic division

Arrested in Prophase from 5th fetal month until the onset of puberty

Will become the first meiotic division at the onset of puberty

Primary oocyte

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Formed after completion of Meiotic I

Release of the first Polar Body during ovulation

Arrested in Metaphase II until fertilization

Completion of 2nd Meiotic Division only occurs if there is fertilization

Secondary oocyte

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Cyclical shedding of the uterine endometrium

Estrogen and progesterone

Uterine/Menstrual cycle

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Periodic changes on the ovary

Gonadotrophic hormones

Ovarian cycle

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A series of changes controlled by hormones that help prepare the female uterus for a possible pregnancy

Average length of 28 days (+/-7days)

Menstrual blood is mainly arterial

Menstrual cycle

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Cyclical ovulation

25-35 day intervals

40 years

400 oppurtunities for pregnancy ➡️ 1200 DAYS (the day of ovulation and its 2 preceeding days

OVARIAN-ENDOMETRIAL CYCLE

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Under LH stimulation, desmolase is activated and cholesterol is converted to PREGNENOLONE

PREGNENOLONE is converted to ANDROGENS, but majority will enter the adjacent granulosa cells to be converted to ESTROGEN

Thecal cells

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Under FSH stimulation, aromatase activity is increased and conversion of ANDROGENS to ESTRADIOL

also release INHIBITIN which also inhibit the release of FSH from anterior pituitary

Granulosa cells

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Inhibit the further release of FSH and LH from anterior pituitary resulting in subsequent decrease in FSH and LH

Act locally on Granulosa cells to increease their sensitivity to FSH and their proliferation resulting in very high level of estrogen during follicular phase

Estradiol (produced by GRANULOSA CELLS)

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EFFECTS OF ESTROGEN DURING FOLLICULAR PHASE

On the uterus: cause of endometrial cells of the uterine mucosal layers to oncrease theri rate of mitotic division (Proliferative phase)

On the cervical mucous:

cause the cervical mucus to be thin and waterey, making the cervix essy for sperm to traverse
cause ferning of the cervical mucous

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EFFECT OF LH SURGE

Triggering of ovulation and follicular rupture

Release of the cumulus-oocyte complex

Induction of the resumption of oocyte meiotic maturation

Luteinization of Granulosa cells

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Peak of LH secretion occurs 10-12 hours before ovulation

Takes place approximately on DAY 14

Allows the release of the oocyte-cumulus complex

Formation of Spinnbarkeit

Pregnancy most likely: the day of ovulation, 2 days preceeding the ovulation

OVULATION

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CORPUS LUTEUM

Luteinization

Corpus hemorrhagicum

Corpus luteum

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A process in which the remains of the Graffian Follicle becomes corpus hemorrhagicum and finally a mature corpus luteum

Luteinization

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Causes MITTELSCHMERZ or midcycle pain

CORPUS HEMORRHAGICUM

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Theca cells + Granulosa cells = Luteal cells or Corpus Luteum

Produce large amount of progesterone

Corpus luteum

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EFFECTS OF PROGESTERONE

On the endometrium:

it causes the uterine endometrium to become secretory, providing a source of nutrients for the blastocyst
presence of subnucleolar vacuoles
stroma becomes edematous

On the cervical mucous: it causes the cervical mucous to become thick

Other systemic effects: it has therrmogenic properties, increase water retention

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Corneal luteum develops from the remains of the dominant or Graafian follicle in process called luteinization

Will regress 9-11 days after ovulation in the absence of pregnancy

Regression of the corpus luteum and drop in the circulating steroid signal the start of events leading to menstruation

The low levels of progesterone (and estrogen) will no longer support the uterus

And the superficial layer of the endometrium will break down

LUTEAL PHASE

NOTABLE HISTOLOGIC CHARACTERISTIC OF THE PREMENSTRUAL PHASE OF THE ENDOMETRIUM

Occurs 1-2 days before menses Infiltration of the stroma by PMN, giving a pseudoinflammatory appearance to the tissue Key to the initiation of ECM breakdown of the functional layer is the infiltration of leukocytes IL8 is the chemotactic activating factor for neutrophils

Spiral arteries coiling become sufficiently severe, resistance to blood flow increase resulting in tissue hypoxia (the most striking and constant event observed in the mestrual cycle is period of vasoconstriction that precedes the onset of mesntruation) The superficial layer is the one that is shed By 5th day of menses, the endometrium has been restored completely The most important factor in the recovery of endometrium after menses is the slight increase in estrrogen in the early follicular phase

MENSTRUATION

Low progesterone Slowly rising estrogen level

Early Follicular phase

Low progesterone Rapidly rising estrogen level

Late follicular phase

Elevated level of progesterone

Luteal phase Pregnancy

Transformation of the secretory endometrium to decidua The highly modified endometrium of pregnancy Dependent on the actions of estrogen and progesterone Dependent on the substances secreted by the blastocyst

DECIDUALIZATION

Decidua layers

Decidua basalis Decidua capsularis Decidua parietalis

Directly beneath the site of blastocyst Will be part of the placenta The spiral arteries loose their smooth muscles and endothelial cells due to invasion of large amounts of trophoblastic cells They become unresponsive to vasoactive agents

DECIDUA BASALIS

Portion overlying the enlarging blastocyst Initially separating if from the uterine cavicty Most prominent durinf he 2nd month of pregnancy The one in contact with chorion Is lost evetually due to obliteration by the growing fetus

DECIDUA CAPSULARIS

Lines the remainder of the uterus Sometimes called the decidua vera during time of development Will remain the same Still the spiral arteries Still responsive to vasoactive agents In contact with chorion later on

DECIDUA PARIETALIS

Events in FERTILIZATION

The sperm binds to zona pellucida of the secondary oocyte and triggers the acrosome reaction, causing release of acrosomal enzymes Sperm penetrates the zona pellucida and unite with the oocyte's plasma membrane, eliciting the cortical reaction and rendering the secondary oocyte impermeable to other sperm Sperm and secondary oocyte cell membranes fuse and contents of the sperm enter the cytoplasm - male genetic material forms the male pronucleus - Tail and mitochondrial degenerate Secondary oocyte completes meiosis II, forming a mature ovum. The nucleus of the ovum is the female pronucleus The male and female pronuclei fuse to form a zygote

POST CONCEPTION WEEK 1

Cleavage Blastocyst formation Implantation

Zygote cytoplasm is successively cleaved to form a blastula, which consists of increasing smaller blastomeres At 32-cell stage, the blastomeres forma morula, which consists of an inner cell mass and outer cell mass The morula enters the utereine cavity at about 3 days post conception

CLEAVAGE

Occurs when fluid secreted within the morula forms the blastocyst cavity Inner cell mass - future embryo, is now called EMBRYOBLAST Outer cell mass - future placenta, is now called TROPHOBLAST

BLASTOCYST FORMATION

Blastocyst implants at around 7 days post conception within the posterior superior wall of the uterus This is during the secretory phase of the menstrual cycle, so implantation occurs within the functional layer of endometrium

IMPLANTATION

POST CONCEPTION WEEK 2

Embryoblast Trophoblast

Differentiates into two distinct cell layers, the Epiblast and Hypoblast, forming a Bilaminar Embryonic Disk EPIBLAST - clefts develop within the Epiblast to form the amniotic cavity HYPOBLAST - form the yolk sac

EMBRYOBLAST

Cytotrophoblast divide mitotically Syncytiotrophoblast - does not divide mitotically - produces the HCG - continues its growth into the endometrium to make contact with the endometrial blood vessels

TROPHOBLAST

EMBRYONIC PERIOD WEEK 3-8

The beginning of the development of major organ system Coincides with the first missed menstrual period Period of high susceptibility to teratogen Gastrulation is a process that establishes the 3 primary germ layers, forming a trilaminar embryonic disk

Germ layers

Ectoderm - CNS & PNS, sensory organs of seeing & hearing, integument layer Endoderm - lining of the GIR and respiratory tract Mesoderm - muscles, cartilages, CVS, urogenital system, rbc

Folic acid must be given before conception

.4 mg (usual dose) 40 mg (hs of pregnancy)

Fetal to maternal: MEMBRANES

Amnion - avascular, provides tensile strength, first identifiable at 7th to 8th day of life, from fetal ectoderm Chorion Decidua parietalis (endometrium) Myometrium Serosa

AMNIOTIC FLUID

Normal amniotic fluid volume: - by 12 weeks = 60ml - by 34-36 weeks = 1L - by term = 840ml - by 42 weeks = 540ml Production of amniotic fluid - initially by amniotic epithelium - fetal kidneys and urine production Amniotic fluid volume is also dependent on the extent of maternal plasma expansion Removal and regulation of amniotic fluid volume - fetal swallowing - fetal aspiration - exchange through skin and fetal membranes

THE PLACENTA AT TERM

Volume 497 ml Weight 508grams (450-500 grams) Surfaces: - fetal: covered with amniotic membrane giving it white, glistening appearance; where the umbilical cord arises - maternal: attached to the decidua, deep bloody appearance arranged into 15-20 irregular lobes, cotyledons Hofbauer cells

CIRCULATION IN THE MATURE PLACENTA

Fetal surface covered by amnion beneath which the fetal chorionic vessels course chorionic villi ➡️ intervillous spsce ➡️ decidual plate ➡️ myometrium

FUNIS

Umbilical cord Two artery, one vein Average length: 55cm WHARTON JELLY - extracellular matrix of specialized connective tissue Anticlockwise spiral is present in 50 to 90 percent of fetuses

PLACENTAL HORMONES

Trophoblast Steroid hormones hPL, hCG, parathyroid hormone-related protein (PTH-rP), calcitonin, relaxin, inhibins, activins and atrial natriuretic peptide Hypothalamic-like releasing and inhibiting hormones: thyrotropin-releasing hormone (TRH), gonadotrophin-releasing hormone (GnRH), corticotrophin-releasing hormone (CRH), somatostatin and growth hormone-releasing hormone (GHRH)

Almost exclusively produced by the placenta Glycoproteins Alpha and beta subunit Functions: rescue and maintenance of function of the corpus luteum, stimulates fetal testicular testosterone secretion, maternal thyroid gland stimulation (chorionic thyrotropins), promotion of relaxin secretion Detectable in plasma of pregnant women 7 to 9 days after the midcycle surge of Lah that precedes ovulation Plasma levels increase rapidly, doubling every 2 days, with maximal levels being attained at 8 to 10 weeks At 10 to 12 weeks, plasma levels begin to decline, and a nadir is reached by about 16 weeks Clearance: mainly hepatic, renal (30%)

hCG | Human chorionic gonadotropin

Similar to hCG Detected in maternal serum as early as 3 weeks Maternal plasma concentrations are linked to placental mass, and they rise steadily until 34-36 weeks Production rate near term: approximately 1g/day Functions: maternal lipolysis, anti-insulin or "diabetogenic", potent angiogenic

hPL | Human placental lactogen

Source: - first 6-7 weeks of pregnancy: CORPUS LUTEUM (ovary) - after 8 weeks: PLACENTA (syncytiotrophoblast) Function: - affects tubal motility, the endometrium, uterine vasculature and parturition - inhibits T-lymphocyte-mediated tissue rejection Preferred precursor of progesterone biosynthesis by the TROPHOBLAST: MATERNAL PLASMA LDL, CHOLESTEROL

PROGESTERONE

Pregnancy near term is hyperestrogenic Produced exclusively by SYNCYTIOTROPHOBLAST Placenta produce all types of estrogen

ESTROGEN

What is the post menopausal estrogen?

ESTRONE

What is the non pregnant estrogen?

ESTRADIOL

What is the placental estrogen?

ESTRIOL