En Dome Trial Cycle

8/14/2019 En Dome Trial Cycle

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Uterine EndometrialUterine Endometrial

CycleCycle



EndometriumEndometrium

1.1. The endometrium is The endometrium isthe mucous membranethe mucous membrane

that lines the inside of that lines the inside of the uterus (womb).the uterus (womb).

2.2. The endometrium The endometriumchanges throughoutchanges throughoutthe menstrual cycle.the menstrual cycle.

3.3. It becomes thick andIt becomes thick andrich with blood vesselsrich with blood vesselsto prepare forto prepare forpregnancy.pregnancy.

4.4. If the woman does notIf the woman does notget pregnant, part of get pregnant, part of the endometrium isthe endometrium isshed, causingshed, causingmenstrual bleeding.menstrual bleeding.



IntroductionIntroduction

Cyclical changes in the endometrium prepareCyclical changes in the endometrium preparefor implantation in the event of fertilization andfor implantation in the event of fertilization andnecessitate menstruation in the absence of necessitate menstruation in the absence of

fertilization.fertilization. The endometrium is divided into two portions. The endometrium is divided into two portions. The functionalis undergoes changes throughout The functionalis undergoes changes throughout

the menstrual cycle and is shed duringthe menstrual cycle and is shed duringmenstruation whilemenstruation while

The basalis remains constant during the The basalis remains constant during themenstrual cycle and regenerates themenstrual cycle and regenerates thefunctionalis each month.functionalis each month.



The uterine endometrial cycle can be The uterine endometrial cycle can be

divided into three phases:divided into three phases:

the follicular or proliferative phase,the follicular or proliferative phase,

the luteal or secretory phase,the luteal or secretory phase,

and the menstrual phase.and the menstrual phase.



FollicularFollicular

Phase/ProliferationPhase/Proliferation

The follicular, or proliferative phase, spans from the The follicular, or proliferative phase, spans from theend of the menstruation until ovulation.end of the menstruation until ovulation.

Increasing levels of estrogen induce proliferation of Increasing levels of estrogen induce proliferation of

the functionalis from stem cells of the basalis,the functionalis from stem cells of the basalis,proliferation of endometrial glands, and proliferationproliferation of endometrial glands, and proliferationof stromal connective tissue.of stromal connective tissue.

Endometrial glands are elongated with narrow lumensEndometrial glands are elongated with narrow lumensand their epithelial cells contain some glycogen.and their epithelial cells contain some glycogen.Glycogen, however, is not secreted during theGlycogen, however, is not secreted during the

follicular phase.follicular phase. Spiral arteries elongate and span the length of theSpiral arteries elongate and span the length of the

endometrium .endometrium . The thickness measures about 3-4 mm The thickness measures about 3-4 mm



Luteal PhaseLuteal Phase

The luteal, or secretory phase, The luteal, or secretory phase,begins at ovulation and lasts untilbegins at ovulation and lasts untilthe menstrual phase of the nextthe menstrual phase of the nextcycle.cycle.

At the beginning of the lutealAt the beginning of the lutealphase, progesterone induces thephase, progesterone induces theendometrial glands to secreteendometrial glands to secreteglycogen, mucus, and otherglycogen, mucus, and othersubstances.substances.

These glands become tortuous These glands become tortuous

and have large lumens due toand have large lumens due toincreased secretory activity.increased secretory activity.

The spiral arteries extend into the The spiral arteries extend into thesuperficial layer of thesuperficial layer of theendometrium..endometrium..



In the absence of fertilization by day 23 of theIn the absence of fertilization by day 23 of themenstrual cycle, the corpus luteum begins tomenstrual cycle, the corpus luteum begins to

degenerate and consequently ovarian hormonedegenerate and consequently ovarian hormonelevels decrease.levels decrease.

As estrogen and progesterone levels decrease, theAs estrogen and progesterone levels decrease, theendometrium undergoes involution.endometrium undergoes involution.

Days 25-26 of the menstrual cycle, endothelin andDays 25-26 of the menstrual cycle, endothelin and

thromboxin begin to mediate vasoconstriction of thethromboxin begin to mediate vasoconstriction of thespiral arteries.spiral arteries.

The resulting ischemia may cause some early The resulting ischemia may cause some earlymenstrual cramps. By day 28 of the menstrualmenstrual cramps. By day 28 of the menstrualcycle, intense vasoconstriction and subsequentcycle, intense vasoconstriction and subsequentischemia cause mass apoptosis of the functionalis.ischemia cause mass apoptosis of the functionalis.

The thickness of the endometrium reaches its The thickness of the endometrium reaches itshighest-5-6mmhighest-5-6mm



Menstrual PhaseMenstrual Phase

The menstrual phase begins as the The menstrual phase begins as thespiral arteries rupture secondary tospiral arteries rupture secondary toischemia, releasing blood into theischemia, releasing blood into theuterus, and the apoptoseduterus, and the apoptosedendometrium is sloughed off andendometrium is sloughed off and

usually lasts four days.usually lasts four days. During this period, the functionalis isDuring this period, the functionalis is

completely shed.completely shed. Arterial and venous blood, remnantsArterial and venous blood, remnants

of endometrial stroma and glands,of endometrial stroma and glands,leukocytes, and red blood cells are allleukocytes, and red blood cells are allpresent in the menstrual flow.present in the menstrual flow.





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