Female Physiology- Raff Flashcards
At what point during development do females have the most oogonia?
Six months into fetal development
What happens to female hormones during the first six months of life?
What is the result?
Large surge of both LH and FSH
We have no idea, but it is theorized to be related to sex changes in brain development between men and women.
What are the three “estrogens”?
Which estrogen is only found in pregnancy?
What is the importance of aromatase?
Estrone, Estradiol, and Estriol
Estriol
Aromatase is necessary for estrogen synthesis from androgens
What hormonal changes are seen prior to puberty?
When does menarche occur?
Increase in FSH and LH starting at 8-9, followed by an increase in estradiol at 10-11
Around 13, but anywhere between 10-15
Describe what’s going on during the menstrual cycle starting from day zero.
- First, an egg needs to mature. The pituitary releases FSH to stimulate follicles.
- One egg (follicle) becomes dominant and generates more and more estradiol
- estradiol produced by the dominant follicle suppresses LH from the pituitary
- The estradiol from the follicle stimulates the uterus to build-up tissue (IE blood and mucus)
- As the egg matures and more estradiol is released, LH suddenly switches to a positive feedback system
- FSH, LH, and estradiol all peak, resulting in ovulation.
- Although the egg is released, the follicle is left behind in the ovary
- The empty follicle (IE corpus luteum) is lonely without it’s egg and produces a whole bunch of progesterone
- The progesterone causes another increase in estrogen. I like to think of this as nostalgia
- Without hCG to rescue it, the corpus luteum withers and without hormones, the body sheds the mucus/blood
What factor other than hormones contribute to menarche?
What signalling molecules mediates this?
Increased body fat signals readiness for menarche
Kisspeptin regulates leptin
What do theca and granulosa cells do?
Where are these cells found?
Theca cells produce androgens, granulosa cells produce estrogens and BOTH produce progesterone.
Ovary
What happens to theca and granulosa cells during ovulation?
How do granulosa cells contribute to the hormone shifts in menstration?
Granulosa cells proliferate as they are stimulated by FSH; Theca cells do nothing as far as I can tell
Granulosa cells accumulate and allow for the estrogen surge which triggers ovulation
Where does fertilization occur?
When does implantation of a blastocyst occur?
In the fallopian tube
Day 5-7
What are trophoblasts?
Why are they important?
cells that surround the blastocyst (very early fetus) and become the placenta
They produce progesterone used as substrate by the fetal adrenals and mom to synthesize androgens. They then turn the androgens into estrogen.
What happens to TSH during pregnancy?
What happens to prolactin during pregnancy?
TSH increases (but dips a bit in the first trimester for some reason)
Prolactin increases steadily throughout the pregnancy
What sex hormones increase in the mother?
Why?
Testosterone
Needed as substrate for the fetus
What happens to the mother’s cardiovascular system during pregnancy:
Blood pressure
Heart Rate
Cardiac output
Volume
Hemoglobin
Blood pressure: drops, but rises (parallel circuits)
Heart Rate: increases (perfuse the fetus/placenta)
Cardiac output: increases (see above)
Volume: increases at the end (parallel circuit requires more blood)
Hemoglobin: decreases (no reason, seems like a bad idea to me, but whatever)
Prior to partuition, prolactin is very high. Why don’t very pregnant women lactate?
High levels of estrogens and progesterones suppress lactation
What does menopause do to gonadotropin levels in the female?
Hint: nuns
During menopause, lack of negative feedback from LH and FSH cause gonadotropin levels to skyrocket
Apparently some nuns support themselves by selling their pee to medical clinics which isolate the gonadotropins for hormone therapies.
