Female Physiology Flashcards by Julia Moulton

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What is genetic sex?

What is gonadal sex?

What is phenotypic sex?

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The yolk sac consists of […] cells that are […] in origin

Hypoblast

Endodermal

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When does the yolk sac form?

4 weeks gestation

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Until week […] the gonads are bipotential
Describe the process of sex determination in the developing embryo.

6
Primordial germ cells from the umbillical vessel (yolk sac) migrate along the dorsal mesentery to the gonadal ridge. Here they begin to for the medulla of testis or ovary and urogenitial mesentery. There are 2 ducts that develop in proximity to the primordial germ cells called Wolffian ducts and Mullerian ducts. These play an important role in dex determination later in development.

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Genetic sex is determined at […] and gonadal sex is determined by […]

Fertilization

Genetic sex

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Describe the process of how a developing embryo’s genetic sex determines it’s gonadal and phenotypic sex.

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In the presence of the […] gene, indifferent gonads develop into testis at […] gestation.

SRY

6 weeks gestation

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What are the roles of leydig and sertoli cells in the developing male embryo?

Testosterone secreted from leydig cells stimulates differentiation of wolffian ducts into male internal genetalia.

Anti-mullerian hormone secreted by sertoli cells causes regression of mullerian ducts, which confers female gonadal and physiological sex.

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What role does testosterone play on androgen sensitive cells?

Androgen sensitive cells convert testosterone to DHT by 5-alpha reductase which causes masculinization of external genitalia

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What must happen at the embryological level to achieve female gonadic and phenotypic sex?

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Describe the development of the uterus and how it can lead to mullerian abnormalities.

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Review the cycle of oogenesis.

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[…] produce oogonia by […] until […] weeks gestation

Primordial germ cells

mitosis

20-24

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What is a primordial follicle?

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[…] is the earliest stage of follicular development

Primordial follicle

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Primary Follicle

Cells that proliferate and what shape they become
What important structure forms between oocyte and follicular cells
Changes seen in late follicular phase
Two types of unique cells types that are seen at this stage

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Describe the attrition of oocytes during human development and lifespan.

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Primary follicles remain arrested in […] until […]

Prophase 1 of meiosis

Puberty

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Secondary Follicles

When do these form?
What hormones stimulate formation of these structures?
What cell population is involved?
Is this gonadotropin dependent or indepenent?
Do we produce only 1 or many follciles at a time?

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What are the effects of FSH on the secondary follicle?

Cause granulosa cells to mulitply

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What cells synthesize and secrete estrogen?

Granulosa cells of primary and secondary follicles, corpus luteum, placenta

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What is the relationship of estrogen and testosterone?

Estrogen is synthesized from androgens in cells that express aromatase. Aromatazation occurs in the cells that produce and secrete estrogen as well as fat, liver, muscle and brain.

What are some important effects of estrogen on the female body?

Stimulates growth of endometrium
Thins cervical mucus
Ductal growth of breast tissue
Antiresorptive effects on bone
Closure of epiphyseal growth plates
Increased thyroid binding globulin and corticosteroid binding globulin

**Progesterone** * Where is this secreted? * How does it travel in blood? * What effects does it produce in body?

* Describe the effects of LH on theca cells in the secondary follicles. * Describe the effects of LH and FSH on granulosa cells in the secondary follicles.

How is it possible for GnRH to stimulate the secretion of two hormones?

* Depends on the pulse frequency of GnRH * High frequency --\> preferential release of LH * Lower frequency --\> preferential release of FSH

After birth, the HPO axis remains quiescent until [...]

Puberty

What 2 phases does puberty consist of?

Adrenarche and Gonadarche

What is adrenarche?

What is Gonadarche?

What is the usual sequence of physical sexual development in females during puberty?

Thelarche (breast development) Pubarche Growth Acceleration Menstruation

What changes occur in thelarche and under what stimulation?

What changes occur during pubarche and under stimulation from what hormone?

**Growth Acceleration** * Peak height velocity begins when and lasts how long? * Implications of this on bones? * Processes that estrogen is stimulating to produce growth? * Implications of this phase on BMI?

**Menarche** * What is this? * What is median age when it happens? When does it occur in relationship to puberty? * What causes this to start and what regulates it once it has started? * What is anovulation?

* First menstrual period * 12.8 y/o; occurs ~2.5 years after onset of puberty * Stimulation of endometrial growth by follicular estrogen; regulated by (+) and (-) feedback from HPO axis * Anovulation is a menstrual cycle without ovulation, common for first 1-2 years due to immature HPO axis

What changes occur in the uterus, cervix and vagina during menarche?

What are the implications of puberty on a female's: * Blood * Skin * Mental state * MSK system * Eyes * Back

When does adrenarche begin? When does gonadarche begin?

~Age 6 ~Age 10

What is precocious puberty? What is a condition that can cause precocious puberty?

Onset of puberty (2 - 2.5 std. dev. earlier than normal, around 8 y/o

What is delayed puberty? What is a condition that can cause it?

**Menopause** * What is it? * How is it determined? * When does it generally happen? * What does it represent physiologically? * What hormonal changes are seen? * What physical changes are seen? * What age demarcates it happening too early?

**Perimenopause** * When does this happen? * What is it / what hormonal and physical changes are observed? * What are common symptoms?

* 4-5 years prior to menopause * Hormonal fluctuations, irregular cycle lengths, anovulatory cycles * Irregular, unpredictable bleeding; hot flashes (vasomotor instability); mood changes

**Menopause** * What are the symptoms of menopause? * What are the long term consequences of menopause?

What is the menstrual cycle? What are the 4 sub cycles in it?

* When is day 1 of menstrual cycle? * What is a normal range of cycle frequency? * What part of the cycle is consistent and for how long? * How long does bleeding occur for? *

In general, what things are happening in the following locations during menstrual cycle? * Hypothalamus/pituitary * Ovaries * Endometrium

When is ovulation?

Depends on cycle length. If cycle is 28 days, ovulation is day 14. If cycle is 21 days, ovulation is day 7. If cycle is 35 days, ovulation is day 21. All of these days are determined by luteal phase, which is consistently 14 days.

What is happening during the follicular phase of menstruation?

FSH from AntPit stimulates growth of a cohort of follicles, which produce estrogen --\> (-) feedback of estrogen on the pituitary keeps FSH levels low --\> Several antral follicles begin the maturation process --\> Only the follicle with the most granulosa cells, FSH receptors, and highest estrogen production becomes the **Dominant Follicle** --\> When the dominant follicle produces blood levels of estrogen \> **200 pg/mL**, estrogen exerts positive feedback on the pituitary to produce the LH surge --\> The LH surge induces oocyte to complete first meiotic division **(arrests at metaphase II)** --\> The oocyte-cumulus complex is released into peritoneum ~36 hrs. after the LH surge: Ovulation! --\> The oocyte is swept up by fimbria of Fallopian tube --\> Second meiotic division is completed only if fertilization occurs

What is the dominant follicle?

The antral follicle with the most granulosa cells, FSH receptors, and estrogen production

What causes estrogen to switch from (-) to (+) feedback on HPO axis?

Dominant follicle producing \> 200 pg/mL of estrogen leads to estrogen having (+) feedback and LH surge

What does the LH surge do for the dominant follicle?

Induces oocyte to complete first meitotic division (now arrested in metaphase 2)

Ovulation occurs [...] after the LH surge

~ 36 hours

What is the luteal phase of menstruation?

What is the proliferative phase of the menstrual cycle?

Refers to the endometrium Estrogen secreted by the developing follicles / dominant follicle causes growth and proliferation of endometrial glands in functional layer of endometrium. Cervical mucus thins.

What is the secretory phase of the menstrual cycle?

Refers to changes happening in endometrium. Progesterone from corpus luteum after ovulation is driving changes. Causes endometrial gland enlargement and maturation. Lumen fills with glycogen rich secretions and cervical mucus thickens. W/o implantation, progesterone levels fall around day 10 post ovulation as corpus luteum degrades into corpus albicans. Blood supply to arteries in endometrim atrophy and cause desquamation of endometrial tissue --\> menstrual phase (bleeding)

What is primary amenorrhea? What is an example of a condition that can cause this?