Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
102 Cards in this Set
- Front
- Back
|
When is sex determined?
|
At conception
|
|
|
What determines a female sex?
|
XX
|
|
|
What is the female XX phenotype?
|
The DEFAULT phenotype; without signals this is what develops.
|
|
|
What is the signal that sways development from the default female phenotype to male?
|
HY (aka SRY)
|
|
|
What do the testes secrete as they develop?
|
-Testosterone
-Mullerian inhibiting factor |
|
|
What do Testosterone and MIF result in?
|
Virilization and a male phenotype, AND the regression of the uterine ducts
|
|
|
What happens in the ABSENCE of both testosterone and MIF?
|
Normal INTERNAL + EXTERNAL female genitalia
|
|
|
How many primordial follicles are women born with?
|
MANY
|
|
|
What are the stages in follicular develoment?
|
1. Primordial
2. Primary 3. Secondary (Antral) 4. Mature (Preovulatory) |
|
|
What are the 2 most important things in the mature follicle?
|
-Granulosa cells
-Ovum |
|
|
What are the Granulosa cells that surround the ovum/antrum?
|
Steroid producing factories
|
|
|
Why is it good that the granulosa cells surround the ovum?
|
Because they BATHE it in the high concentration of hormones being produced.
|
|
|
What is left of the follicle after ovulation?
|
Corpus luteum
|
|
|
What does the corpus luteum produce?
|
Progesterone (primarily)
Estrogen |
|
|
What happens to the CL if pregnancy doesn't occur?
|
It dies and leaves a little scar called corpus albicans
|
|
|
What happens to the CL if pregnancy does occur?
|
hCG from the placenta rescues the corpus luteum
|
|
|
What are the germ cells in women called?
|
Oogonia
|
|
|
When do oogonia get produced?
|
Before birth in utero
|
|
|
What happens to the number of oogonia in the fetus before birth?
|
-2 mo old fetus has about 6000
-6 mo fetus has ~7 million -At birth, only ~2 million left - they die off (PCD) |
|
|
What happens to the number of oogonia in females after birth?
|
It continually declines until menopause
|
|
|
So is it the menstrual cycle that determines whether oogona will die off?
|
No; if they're ovulated they'll die (w/out fertilization) but without ovulation they'll die anyway. Independent
|
|
|
What are the FIRST hormones to rise in a female fetus beginning at conception?
|
hCG + LH + FSH
|
|
|
What is similar about hCG and FSH/LH?
|
They all are proteins, share homology - with TSH too
|
|
|
What is hCG produced from?
|
The trophoblast cells - placenta
|
|
|
What is FSH/LH produced from?
|
The baby
|
|
|
When does hCG peak?
When do FSH/LH peak? |
hCG peaks at 10 weeks
FSH/LH peak at 20 weeks |
|
|
What makes FSH/LH peak and begin to decline in the fetus at 20 wks gestation?
|
The hypothalamic-pituitary axis turns on:
-GnRH pulses begin -Stimulate fetal FSH/LH |
|
|
What is the function of turning on FSH/LH with the pituitary?
|
Production of oogonia! This is when they begin to increase significantly in number.
|
|
|
What happens to FSH and LH after hte # of oogonia peak at 6 million?
|
FSH/LH decline
|
|
|
When does FSH/LH surge in the baby?
|
At 2-4 months
|
|
|
Why do FSH/LH surge in a 2month old?
|
We're not sure; maybe the sexual differentiation of the brain.
|
|
|
Do FSh/LH levels change during childhood in a female?
|
No not really
|
|
|
When do FSH/LH begin to climb in a female girl?
|
At about 10 years
|
|
|
Does the menstrual cycle begin right when FSH/LH levels increase?
|
No - the hormones increase LONG before menarche occurs.
|
|
|
By what age do most women have normal menstrual cycles?
|
16 yrs
|
|
|
What are the primary gonadal steroid hormones that occur in women who are not pregnant?
|
-Estradiol
-Estrone |
|
|
What 2 additional estrogens occur primarily in pregnant women?
|
-Progesterone
-Estriol |
|
|
Why is progesterone called that?
|
Because it HELPs (pro) Gestation (gesterone)
|
|
|
Do women make androgens?
|
YES
|
|
|
Why do women make androgens?
|
Because in order to make estrogens you HAVE to make androgens
|
|
|
What is SHBG?
|
Steroid hormone binding globulin
|
|
|
What is SHBG really designed to carry?
|
Androgens - testosterone and DHT
|
|
|
Does SHBG bind estrogens?
|
Yes
|
|
|
What are MOST of the circulating estrogens bound to?
|
Albumin
|
|
|
So what 2 proteins bind
-Estradiol; what does it prefer? -Cortisol; what does it prefer? -Progesterone; prefer? |
-Estradiol binds Alb + SHBG; prefers to bind to albumin
-Cortisol binds Alb + CBG; prefers to bind to CBG -Prog binds Alb + CBG; prefers to bind to albumin |
|
|
What is the signal that turns on puberty?
|
Bottom line: nobody really knows
|
|
|
What is the current and accepted theory for the puberty signal?
|
1. Body puts on fat
2. Fat secretes Leptin 3. Leptin reaches brain and shows there's enough fat to support reproduction |
|
|
What is the first hormone that increases when GnRH pulses begin to increase in a 10yr old female?
|
FSH
|
|
|
What does FSH do when it first increases at puberty onset?
|
Wakes up the ovary
|
|
|
What are the 2 hormones that go up after the ovary wakes up?
|
-LH
-Estradiol |
|
|
What other hormone do we know is stimulated by gonadotropins?
|
GROWTH HORMONE!
|
|
|
So what 3 changes occur as a result of the increasing FSH/LH, Estradiol, and GH?
|
-Growth spurt
-Breast development -Pubic hair sprouts |
|
|
What do we NOT see occuring right away? Why?
|
The menstrual cycle - it takes a long time for the whole system to get its act together.
|
|
|
What are the 3 phases of the menstrual cycle?
|
1. Menstrual phase
2. Follicular phase 3. Luteal phase |
|
|
What causes the menstrual phase?
|
The loss of corpus luteum due to lack of hCG when pregnancy does not occur
|
|
|
What do we call the result of progesterone loss when the CL dies?
|
Withdrawal bleeding
|
|
|
What happens to the gonadotropin levels at the early menstrual phase?
|
They increase due to the loss of neg feedback of progesterone when the CL died
|
|
|
What is the purpose of FSH and to a lesser extent LH rising as the menses phase ends?
|
To stimulate the next round fo 6-8 follicles to mature
|
|
|
What do the follicles begin to do as they mature?
|
Make estrogen!
|
|
|
How does the estrogen from the maturing follicles affect the pituitary?
|
The estrogen induces negative feedback and inhibits FSH/LH release
|
|
|
So what's going on with our hormones at the beginning of the follicular phase?
|
-Follicles are making estrogen
-Pituitary is being inhibited form making LH/FSH |
|
|
If FSH is what stimulates follicular development, how can the follicle continue to develop when it inhibits pituitary release of FSH?
|
As one follicle becomes dominant, the estrogen it secretes becomes positive feedback!
|
|
|
When does estrogen production from a dominant follicle become positive feedback?
|
At midfollicular phase
|
|
|
What does "Positive Estrogen Feedback" by a dominant follicle entail?
|
1. Local autocrine effects to increase MORE estrogen production
2. Systemic effects by increasing LH receptor expression on the follicle |
|
|
Why do we say the increased LH receptor expression is a systemic effect?
|
Because it allows the LH surge to exert its effect when the feedback by estrogen from the dominant follicle switches over to POSITIVE on the pituitary.
|
|
|
So how many cases of positive feedback occur during the follicular phase?
|
2 - estrogen has both local pos feedback and systemic pos feedback.
|
|
|
What happens at the end of the follicular phase?
|
Estrogen is stimulating LH/FSH, and LH/FSH are stimulating the follicle to make more estrogen until OVULATION occurs.
|
|
|
What happens to estrogen levels after ovulaton, during the luteal phase? Why?
|
They fall off significantly because the follicle that was producing estrogen was ovulated!
|
|
|
What happens to progesterone levels after ovulation during the luteal phase? Why?
|
They surge - because the corpus luteum makes progesterone
|
|
|
What happens to LH/FSH during the luteal phase? Why?
|
They are low - because progesterone has negative feedback on the pituitary.
|
|
|
What happens at the end of the luteal phase if pregnancy does not occur?
|
1. No Trophoblast to secrete HcG
2. No rescuing of CL 3. No CL to make progesterone 4. LH/FSH begin to rise |
|
|
And what do we know LH/FSH do at the beginning/during the menstrual phase?
|
Stimulate the growth and maturation of more follicle cells!!
|
|
|
If you see the word pulsatile, think:
|
GnRH and LH/FSH
|
|
|
What are the 2 cells in the "2 cell hypothesis of ovarian steroidogenesis control"?
|
1. Theca cells
2. Granulosa cells |
|
|
What are theca and granulosa cells analogous to in males?
|
Theca = Leydig
Granulosa = Sertoli |
|
|
What is happening to granulosa cells at the end of the follicular phase?
|
They are proliferating dramatically due to the pos fb of estrogen from the dominant follicle.
|
|
|
How do you remember what hormones stimulate what steroid sex hormone secreting cells?
|
Little Figs -> LTL FGS
LH - Theca / Leydig FSH - Granulosa/Sertoli |
|
|
What hormone do the Theca cells produce?
|
ANDROGENS
|
|
|
If you measure estrogen in ANYBODY what do you know they produced? Why?
|
Androgens - because they are the precursor for ALL estrogens.
|
|
|
What enzyme is needed to produce estrogens from androgens?
|
Aromatase
|
|
|
What cells have aromatase?
|
Granulosa cells
|
|
|
Do granulosa cells always only express FSH receptors?
|
NO - remember that's the whole point of estrogen pos feedback during midfollicular phase - so that the granulosa cells will respond to the LH surge and make a ton of estrogen.
|
|
|
Can granulosa cells make androgens?
|
No
|
|
|
What are the 2 things that the granulosa cells can do?
|
1. Convert cholesterol to pregnenolone
2. Convert androgen to estrogen |
|
|
Where do the granulosa cells get androgens to convert to estrogen?
|
From the theca cells
|
|
|
What are the 3 organs in the female reproductive tract that Estrogen and Progesterone act on?
|
1. Oviducts
2. Uterus 3. Vagina |
|
|
What are the 2 components of the oviducts?
|
-Lining
-Muscular wall |
|
|
How does Estrogen affect the oviduct lining and muscular wall? (its high during follicular phase)
|
Lining: increases cilia formation and activity
Muscular wall: increases contractility |
|
|
How does Progesterone affect the oviduct lining and muscular wall during the luteal phase?
|
Lining: increases secretion
Muscular wall: decreases contractility |
|
|
What are the 3 components of the Uterus?
|
-Endometrium
-Myometrium -Cervical glands |
|
|
What is the Follicular phase of the menstrual cycle equivalent to in the uterine cycle? What is the luteal phase equivalent to?
|
Follicular = Proliferative
Luteal = Secretory |
|
|
So when is Estrogen high?
When is Progesterone high? |
Estrogen = proliferative phase
Progest = Secretory phase |
|
|
What is the effect of estrogen on the uterus endometrium? Myometrium? Cervical glands?
|
Endo = proliferation
Myo = increased growth and contractility Glands = watery secretion |
|
|
What is the effect of progesterone on the uterus endometrium? Myometrium? Cervical glands?
|
Endo = differentiation and secretion
Myo = decreased contractility Glands = dense/viscous secretion |
|
|
Why would you want a watery secretion during the proliferative/follicular phase?
|
So sperm can get through
|
|
|
Why would you want a dense/viscous secretion during the luteal/secretory phase?
|
To prevent bacteria from getting in because now fertilization could have occurred.
|
|
|
How does Estrogen affect the vagina?
|
-Increases epithelial proliferation
-Increases glycogen deposition |
|
|
How does Progesterone affect the vagina?
|
-Decreases epithelial proliferation
-Increases epithelial differentiation |
|
|
So what is the Proliferative phase of the endometrial cycle (in general)? What is it under the influence of? What phase of the menstrual cycle is it equiv to?
|
The phase of endometrial and myometrial growth
-Under Estrogen influence -Analogous to the follicular phase of the menstrual cycle |
|
|
What is the Secretory phase of the endometrial cycle (in general)? What is it under the influence of? What phase of the menstrual cycle is it equiv to?
|
-Lots of glycogen rich product production - fluffing up the pillow for implantation
-Under Progesterone influence -Equiv to Luteal phase |
|
|
If pregnancy doesn't occur what happens?
|
Menstruation due to loss of progesterone causing withdrawal bleeding.
|
|
|
What 'withdraws' in withdrawal bleeding?
|
The spiral arteries vasoconstrict
|
