PMS III Week 1 - Female Reproductive Physiology/Pathophysiology

Why is embryology important in reproductive physiology?

Embryology helps explain the spread, growth, and routes of reproductive cancers; possible congenital defects; and diagnosis/treatment of reproductive dysfunction.

What determines the genetic sex of the embryo?

The X or Y chromosome carried by the sperm determines the genetic sex of the embryo.

What gene on the Y chromosome promotes male reproductive development?

The SRY gene encodes for development of the male reproductive system.

What promotes female reproductive development?

The WNT4 gene, along with lack of SRY, encodes for female reproductive system development.

Until when are embryonic gonads undifferentiated?

Gonads are undifferentiated until about 7 weeks after fertilization.

Until when are external genitalia undifferentiated?

External genitalia are undifferentiated until about 12 weeks after fertilization.

What hormones influence external genitalia development?

Androgens influence development of external genitalia.

What is the reproductive consequence of congenital adrenal hyperplasia in a female fetus?

CAH causes decreased cortisol, leading to compensatory increased androgens; this can virilize female fetuses and cause ambiguous external genitalia.

Why does CAH cause increased androgens?

Decreased cortisol causes a compensatory increase in androgen production.

What embryologic tissue forms the urogenital ridges?

Intermediate mesoderm forms the urogenital ridges.

What do the urogenital ridges form?

The urogenital ridges form the ovaries.

What happens to primordial germ cells during ovarian development?

Primordial germ cells migrate to the genital ridges and become oogonia.

What do oogonia in the genital ridge form?

Oogonia in the genital ridge form the ovary.

Where do the ovaries migrate during development?

The ovaries migrate from the body cavity to the pelvis.

What structures form from connections within the body cavity during ovarian migration?

The ovarian ligament and round ligament form from connections within the body cavity.

What are the two major embryologic genital duct systems?

The mesonephric, or Wolffian, ducts and the paramesonephric, or Müllerian, ducts.

What do the mesonephric/Wolffian ducts form in males?

They form the epididymis, ductus deferens, and ejaculatory ducts.

What happens to the mesonephric/Wolffian ducts in females?

They degenerate.

What do the paramesonephric/Müllerian ducts form in females?

They form the fallopian tubes, uterus, and upper portion of the vagina.

What happens to the paramesonephric/Müllerian ducts in males?

They degenerate.

What is the high-yield female derivative of the Müllerian ducts?

Fallopian tubes, uterus, and upper vagina.

What is the high-yield male derivative of the Wolffian ducts?

Epididymis, ductus deferens, and ejaculatory ducts.

Why are renal anomalies associated with Müllerian anomalies?

The paramesonephric system develops alongside the renal system, so abnormalities in one system are frequently associated with abnormalities in the other.

What reproductive anomaly may be associated with unilateral renal agenesis?

A woman with unilateral renal agenesis may also have an ipsilateral abnormal fallopian tube.

Does absence of one fallopian tube predict absence of the ovary?

No. Despite their functional connection, lack of one does not indicate a probable lack of the other.

What can incomplete fusion of the paramesonephric ducts cause?

Incomplete fusion can lead to variant uterine shapes.

What can premature degeneration of the paramesonephric ducts cause?

Premature degeneration can lead to an absent uterus.

What vaginal abnormalities can occur with Müllerian abnormalities?

Vaginal abnormalities can occur, and uterine and vaginal agenesis can occur together.

Are vulvar/external genital abnormalities usually associated with Müllerian abnormalities?

No. Vulva and external genitalia are not usually associated with Müllerian duct abnormalities.

What embryologic structures form the external genitalia?

Genital swellings in the pelvis form the external genitalia.

What separates the urogenital sinus from the anorectal canal?

The urorectal septum separates the urogenital sinus from the anorectal canal.

What does the genital tubercle become in female development?

The genital tubercle becomes the clitoris in the presence of estrogens and absence of androgens.

What do the urogenital folds become in female development?

The urogenital folds become the labia minora.

What do the labioscrotal swellings become in female development?

The labioscrotal swellings become the labia majora.

What are the boundaries of the greater/false pelvis?

The greater pelvis is bounded by the lumbar vertebrae posteriorly, iliac fossae bilaterally, and abdominal wall anteriorly.

What forms the lesser/true pelvis?

The lesser pelvis is formed by the sacrum and coccyx posteriorly and the ischium and pubis laterally and anteriorly.

What does the lesser/true pelvis contain?

It contains the pelvic viscera: uterus, vagina, bladder, fallopian tubes, ovaries, distal rectum, and anus.

What pelvic organs are included in the true pelvis?

Uterus, vagina, bladder, fallopian tubes, ovaries, distal rectum, and anus.

What is the obstetric conjugate?

The obstetric conjugate is the narrowest fixed distance that the fetal head must pass through during vaginal delivery.

Why can't the obstetric conjugate be measured directly?

It cannot be measured directly because of the presence of the bladder.

How is the obstetric conjugate calculated indirectly?

It is calculated by measuring the diagonal conjugate and subtracting 1.5 to 2 cm.

What is the diagonal conjugate?

The diagonal conjugate is the distance from the lower border of the pubis anteriorly to the lower sacrum at the level of the ischial spines.

How much shorter is the obstetric conjugate than the diagonal conjugate?

The obstetric conjugate is 1.5 to 2 cm shorter than the diagonal conjugate.

What obstetric conjugate measurement is generally needed for vaginal delivery of a normal-sized fetal head?

The obstetric conjugate should generally be 11.0 cm or greater.

What are the four pelvic types?

Gynecoid, anthropoid, android, and platypelloid.

What is the most common pelvic type?

Gynecoid pelvis, occurring in about 40-50%.

What percentage of pelvises are anthropoid?

About 25%.

What percentage of pelvises are android?

About 20%.

What percentage of pelvises are platypelloid?

About 2-5%.

Can a person's pelvis be a mixture of pelvic types?

Yes. Pelvic types can be mixed and not exactly one type or another.

What structures are included in the vulva?

The vulva includes the labia majora, labia minora, mons pubis, clitoris, vestibule, and ducts of the Skene and Bartholin glands.

What is the broad definition of the perineum?

The perineum is the general area between the thighs extending from the coccyx to the pubis.

What is the narrow clinical definition of the perineum?

The perineum is the area between the vagina and the anus.

What is the external os?

The external os is the opening of the uterus to the vagina.

What shape is the external os in nulliparous women?

The external os is round in nulliparous women.

What shape is the external os after childbirth?

The external os becomes a transverse slit after childbirth.

What are the layers of the uterus listed in the presentation?

The uterus includes the endometrium and myometrium.

What are the layers of the endometrium?

The endometrium has a functional layer and a basal layer.

Which endometrial layer is shed during menstruation?

The functional layer is shed during menstruation.

Which endometrial layer remains after menstruation?

The basal layer remains after menstruation.

What cells are found in the ovary and are important for hormone production?

Theca cells and granulosa cells.

What are ovarian functions listed in the presentation?

The ovaries secrete sex hormones, produce estrogen and androgens, develop and release ova, and secrete progesterone.

What is the role of the fallopian tubes?

The ova travel from the ovary to the uterus through the fallopian tubes.

What does a hysterosalpingogram evaluate?

An HSG visually evaluates the structure of the uterus and fallopian tubes.

How is an HSG performed?

Dye is injected into the uterus and watched to see whether it fills the fallopian tubes and spills into the pelvis.

What does spill of dye into the pelvis during HSG indicate?

It suggests that the fallopian tubes are open.

What is anteversion of the uterus?

Anteversion means the uterus is tilted forward.

What is midposition of the uterus?

Midposition means the uterus is slightly forward but functionally straight.

What is retroversion of the uterus?

Retroversion means the uterus is tilted backward.

What is anteflexion of the uterus?

Anteflexion means the top of the uterus folds forward.

What is retroflexion of the uterus?

Retroflexion means the top of the uterus folds backward.

Can the uterus tilt laterally?

Yes. The uterus can also be tilted to the right or left.

What causes uterus didelphys?

Uterus didelphys occurs when the inferior parts of the Müllerian ducts do not fuse.

What is uterus didelphys?

Uterus didelphys is a double uterus caused by failure of fusion of the inferior Müllerian ducts.

What vaginal findings may occur with uterus didelphys?

It may be associated with a double vagina or a single vagina.

What causes a bicornuate uterus?

A bicornuate uterus results when lack of Müllerian duct fusion is limited to the superior portion of the uterine body.

What is a bicornuate uterus with rudimentary horn?

It occurs when one duct is poorly developed and does not fuse with the other duct, producing a bicornuate uterus with a rudimentary horn.

What is puberty?

Puberty is the onset of sexual maturation.

What is the average age of puberty onset in females?

The average age is 8-9 years old.

What is the average age of puberty onset in males?

The average age is 11 years old.

What happens to the pituitary before puberty begins?

The pituitary becomes more sensitive to GnRH and begins releasing more LH and FSH.

What is gonadarche?

Gonadarche is gonadal maturation stimulated by LH and FSH.

What hormones do LH and FSH increase during puberty?

They increase estradiol secretion in females and testosterone secretion in males.

What does estradiol cause during female puberty?

Estradiol causes breast development, reproductive organ maturation, increased fat deposits, and skeletal growth.

What is thelarche?

Thelarche is breast development caused by estradiol.

What does testosterone cause during male puberty?

Testosterone causes maturation of the reproductive organs.

What is menarche?

Menarche is cyclic menstrual bleeding.

What is the average age of menarche?

The average age is 12 years old.

What is the normal age range for menarche listed in the presentation?

The range is 9-17 years old.

What is the normal menstrual cycle length?

The menstrual cycle is 28 days plus or minus 7 days.

What is the HPO axis?

The hypothalamic-pituitary-ovarian axis controls the menstrual cycle.

What does the hypothalamus release in the menstrual cycle?

The hypothalamus releases pulsatile bursts of GnRH.

What does GnRH stimulate?

GnRH stimulates the anterior pituitary to release pulsatile bursts of LH and FSH.

What do LH and FSH stimulate the ovary to release?

They stimulate the ovary to release sex hormones, including estrogen and testosterone.

What is Day 1 of the menstrual cycle?

Day 1 is the first day of menses.

Why does menses occur if conception does not happen?

Progesterone and estrogen decline, leading to menstrual bleeding.

How long does menses usually last?

Menses usually lasts 3-7 days.

What two cycles occur simultaneously during the menstrual cycle?

The ovarian cycle and endometrial cycle occur simultaneously.

What are the major ovarian cycle phases?

Follicular phase, ovulation, and luteal phase.

What are the major endometrial cycle phases?

Menstrual/ischemic phase, proliferative phase, and secretory phase.