Physiology Flashcards
sources of estrogen
ovary –>17B-estradiol placenta –> estriol adipose –> estrone
potency of estrogen types
estradiol > estrone > estriol
function of estrogen
-development of genatalia, breast, and female fat distribution -growth of follicle, endometrial proliferation, and myometrial excitability -upregulation of estrogen, LH, and progesterone receptors; feedback inhibition on LH and FSH; then LH surge; stimulation of prolactin secretion -increases transport proteins, SHBG; increases HDL and decreases LDL
in pregnancy, what happens to estradiol, estrone, and estriol
estradiol and estrone are increased by 50-fold estriol increases by 1000fold –> indicator of fetal well being
estrogen receptors are expressed in ______ and translocate to________
the cytoplasm; the nucleus when bound by ligand
sources of progesterone
corpus luteum, placenta, adrenal cortex, testes
function of progesterone?
- stimulates endometrial secretions and spiral artery development
- pregnancy maintenance
- decreased myometrial excitability
- production of thick cervical mucus (inhibits sperm entry into the uterus)
- increases body T
- inhibits gonadotropins (LH FSH)
- uterine SM relaxation
- decreased estrogen receptor expressivity
- prevents endometrial hyperplasia
After delivery, pregesterone _______; why?
falls
this disinhibits prolactin and allows lactation
increased progesterone is indicative of?
ovulation
progesterone –>
prolactin –>
pro-gestation
pro-lactation
tanner stages of sexual development
each category can have separate stages
ex: stage 2 genatalia and stage 3 pubic hair
length of follicular phase vs luteal phase of menstruation
follicular varies in length
luteal is usually 14 days
decrease in progesterone leads to decreased…
fertility
estrogen stimulates…
progesterone maintains…
estrogen –> endometrial proliferation
prog –> endometrium to support implantation
oligomenorrhea
>35 day cycle
polymenorrhea
<21 day cycle
metrorrhagia
intermenstrual bleeding
frequent but irregular menstruation
menorrhagia
heavy menstrual bleeding
>80mL blood loss or >7 days of menses
menometrorrhagia
heavy, irregular menstruation at irregular intervals
increased estrogen leads to –> a –> b –> c –> d –> e
a - LH surge
b - ovulation
c - progesterone from corpus luteum
d - progesterone falls
e - mestruation (apoptosis of endometrial cells)
oogenesis/spermatogenesis
primary oocytes
are 2N, 4C (46 sister chromatids)
begin meiosis I during fetal life and complete meiosis I just prior to ovulation
in oogenesis
meiosis I is arrested in_____ for _____
meiosis II is arrested in _____ until ____
1 - prophase 1 for years until ovulation (primary oocytes)
2 - metaphase II until fertilization (secondary oocytes) –> “until an egg MET a sperm”
what happens to secondary oocyte if fertilization does not occur?
if it doesnt occur within 1 day, secondary oocyte degenerates
ovulation physiology
increased estrogen –> increased GnRH receptors on anterior pituitary –> estrogen surge then stimulates LH release –> ovulation (rupture of follicle)
increased temperature (progesterone induced)
mittelschmerz
transient mid-cycle ovulatory pain; associated with peritoneal irritation (ffollicular swelling, fallopian tube contraction)
can mimic appendicitis
where does fertilization most often occur?
upper end of fallopian tube (ampulla) within 1 day of ovulation
when does implantation occur?
6 days after fertilization into the wall of the uterus
preganancy detection
1 week after conception –> can detect hCG in blood (secreted by syncytiophoblasts)
2 weeks after conception –> detectable on home urine test
pregnancy
lactation physiology
after labor, the decrease in progesterone and estrogen disinhibits lactation
suckling is required to maintain milk production since increased nerve stimulation increased ocytocin and prolactin
prolactin
induces and maintains lactation and decreases reproductive functon
oxytocin
assists in milk letdown; promotes uterine contractions
breastmilk is ideal for infants less than ___
why?
6 months
it contains maternal immunoglobulins to confer passive immunity (IgA), macrophages, and lymphoctes
this reduces infant infections and is associated with decreased risk to development of allergies, asthma, diabetes,and obesity
exclusively breastfed infants require…
vitamin D supplements
for the mother, breastfeeding reduces…
risk of breast and ovarian cancer
hCG
source and function
syncytiotrophoblast of placenta
- maintains corpus luteum and progesterone for 1st trimester by acting like LH
- used for pregnancy detection since it appears by 2 weeks in urine
in 2nd and 3rd trimesters, the placenta synthesizes its own what? this causes what?
its own estriol and progesterone and the corpus luteum degenerates
menopause
decreased estrogen production due to age-linked decline in number of ovarian follicles ; around 51 yo (earleir in smokers)
- usually preceded by 4 or 5 abnormal menstrual cycles
- increased FSH since there is a loss of negative FSH feedback due to decreased estrogen
source of estrogen after menopause
estrone from peripheral converstions of androgens
menopause hormonal changes
decreased: estrogen
increased: FSH, LH, and GnRH
menopause causes what side effects?
HAVOCS
hot flashes
atrophy of vagina
osteoporosis
coronary artery disease
sleep disturbances
spermatogenesis
begins at puberty with spermatogonia “(gonium is going to be a sperm”)
full development takes 2 months
occurs in seminiferous tubules
produces spermatids that undergo spermiogenesis (loss of cytoplasmic contents and gain of acrosomal cap) to form mature spermatozoon (“zoon is zooming to the egg”)
three androgens
testosterone
DHT (dihydrotestosterone)
androsteredione
sources of androgens?
potency ranking?
DHT and testosterone from testis
andorstenedione from adrenal glands
potency: DHT> testosterone > androstenedione
what converts testosterone to DHT?
enzyme 5alpha reductase
in the male, androgens are converted to estrogen by
cytp450 aromatase
testosterone functions
- differentiates male genitalia except the prostate
- growth spurt: increased penis size, sperm, muscles, RBCs, and seminal vesicles
- deepens voice
- libido
- closes epiphyseal plates
DHT functions
early –> differentiates penis, scrotum, and PROSTATE
late –> prostate growth, balding, sebaceous gland activity
