Reproductive Lecture 4 Flashcards
What drug results in an unusually high FSH/LH/testosterone?
clomiphene
Define primary amenorrhea
absence of menses by age 17
causes: Turner’s, complete androgen resistance, hormonal disorders
Define secondary amenorrhea
cessation of menstruation for longer than 6 months
causes: pregnancy, lactation
What is galactorrhea?
inappropriate milk production in someone who is not lactating (can be caused by prolactinomas)
Define oligomenorrhea
infrequent periods (cycle length >35 days)
causes: changes in CNS mechanisms that regulate GnRH release
Define dysmenorrehea
painful menses due to uterine contractions (prostaglandin synthesis promoted by E2)
Painful periods are due to which hormone?
prostaglandins
What are some causes of hirsutism (excessive hair growth)
excessive androgen production by adrenals
What differentiates hirsutism from virilization?
virilization includes more evidence of androgen stimulation like clitoral hypertrophy, deepening voice, balding
What is PMS?
Premenstrual syndrome
What is PCOS?
polycystic ovarian syndrome
root cause: insulin resistance, obesity
How is PCOS related to insulin?
high insulin stimulates androgen production (leading to infertility) and increased conversion to estrogens (weight gain)
What is the cause of the cysts in PCOS?
follicles degenerate into cysts, ovaries get really big
What are some symptoms of PCOS?
- sleep apnea
- menstrual irregularity
- obesity/acne
- hirsutism
What are treatments for PCOS?
metformin (can restore fertility)
Clomiphene (feedback on HPT axis)
Is fetal age the same as gestational age?
NO, fetal age is 2 weeks less than gestational age (which is calculated from first day of last menstruation)
When is the best chance for fertilization?
24 hours post-ovulation (48-72 hours post coitus for sperm)
What is the acrosomal reaction?
release of proteolytic enzymes that disperse granulosa cells and permit sperm attachment to ZONA PELLUCIDA
How are the enzyme rich contents of the acrosome released?
spermatozoan has receptors for glycoprotein (ZP3) so binding causes inreased IP3 leading to increased Ca++ which fuses inner and outer membranes
What is the first exocytosis step of fertilization?
1) exocytosis of spermatozoan internal membrane contents
Name the steps of fertilization
1) binding of sperm to zona pellucida
2) acrosomal reaction
3) penetration thru zona pellucida
4) fusion of plasma membrane
5) sperm nucleus enters egg cytoplasm
What is the second exocytosis event of fertilization?
release of oocyte’s internal vesicles (harden glycoproteins of zona pellucida preventing polyspermy)
Why is the Ca++ increase so important upon fertilization?
1) allows both exocytosis events
2) triggers completion of second meiotic division
How long do sperm retain fertilizing capacity?
24-48 hours
What percentage of sperm make it to the oviduct? ampulla?
0.1% to oviduct
a few hundred to the ampulla
Does the vagina make sperm transport easier or harder?
easier (decreased acidity, increased cGMP to increase velocity and direction of sperm) contraction of ampulla wall to promote random interaction of sperm and ovum
For how long does the blastocyst traverse the oviduct?
3 days
What determines the timing of blastocyst entry into the uterus?
estrogen/progesterone balance
estrogen constricts isthmus, barring passage of embryo to uterus to allow time for endometrial development
progesterone promotes myometrium relaxation and transport of blastocyst to uterus
What are the 3 successive processes of implantation?
1) adhesion
2) penetration
3) invasion
What is the implantation failure rate?
70%
What important cytokine increases integrins in endometrial cells (promoting implantation)?
IL-1
What does osteopontin do/
binds integrins of both endometrium and blastocyst
The egg hatches when ____________________
the zona pellucida dissolves
What do stromal cells do?
form decidua and secrete nutrients (becomes barrier and endocrine organ later)
Describe the burrowing and intermingling of endometrial cells and the egg
microvilli of trophoblasts interdigitate with endometrial cells then burrow under epithelial cells
What hormone promotes the formation of the decidua from stromal cells?
progesterone
What is the source of nutrients for the egg until vasculature can be established?
decidua
What is invasion?
balance between decidual cells (defense) and trophoblast migration (offense)
to prevent from burrowing too deeply
What do trophoblasts secrete to help with burrowing? (and is blocked by decidual cells)
matrix metalloproteinases (MMP)
What 2 things do trophoblasts differentiate into?
1) syncytiotrophoblasts
2) cytotrophoblasts
What are syncytiotrophoblasts?
mass without ell boundaries, extend between uterine epithelial cells
What do syncytiotrophoblasts secrete?
TNF
What do Cytotrophoblasts serete?
CRH and TRH
somatostatin
Which of the two (syn or cyto) are responsible for most endocrine functions?
syncytiotrophoblasts
What are 4 main functions of the placenta?
1) Gut (supplies nutrients)
2) Lung (gas exchange)
3) Kidney (fluid volume and waste disposal)
4) Endocrine gland
How are nutrients transported to fetus?
diffusion of facilitate diffusion
oxygen diffuses down conc gradietn (fetal Hb has higher affinity for O2 than adult)
How is CO2 transferred from fetal to maternal blood to be exhaled?
CO2: pCO2 in fetal blood is 2-3mmHg higher than maternal blood so it can diffuse down that gradient
What is hCG and what other hormone is it similar to?
secreted by fertilized baby (can be detected 9 days post conception) made by syn under control of GnRH from cyto
similar to LH (rescues the luteum and stimulates secretion of progesterone and estradiol)
What effect does hCG have on LH and FSH?
prevents it (otherwise would stimulate next cohort of follicles to develop)
complemented by inhibin
What other hormone is produced by sync that is structurally similar to GH?
Human placental lactogen (HPL) aka Human Chorionic Somatomammotrophin (HCS)
What does HPL do?
in response to hypoglycemia, it stimulate lipolysis and has anti-insulin actions on maternal carb metabolism (increases plasma glucose and FFAs to maintain continuous flow of nutrients to baby)
