reproduction - F repro pt 2 Flashcards
Primary amenorrhea – what is it, and what are common causes
Absence of menses in phenotypic female by age 17
Causes:
Disorders of sexual differentiation such as turner syndrome (XO), cmplete androgen resistance (XY), and hormonal disorders in ovaries, , adrenals, thyroid, HPA axis
Secondary amenorrhea - what is it and what are common causes (as well as others)
Cessation of menses for >6 months
Common causes: Pregnancy, lactation, and menopause
Others: Prolactinoma, panhypopituitarism
Oligomennorrhea – Common causes , and some other causes
Infrequent periods, cycle lengths >35 days
Changes due to functional abnormalities in CNS mechanisms that regulate GnRH release including stress and illness
Changes in body fat composition, intense exercise, extreme weight loss , anorexia nervosa - no consistent changes in plasma gonadotropins or ovarian steroids
What is clomiphene
First used to treat oligomenorrhea; blocks estrogen receptors in brain; makes it useful as a fertility drug because induces HPG axis from lack of negative feedback; induces ovulation in PCOS
Dysmenorrhea
Painful menses related to uterine contractions ; main involve pelvic pain radiating to back, thighs, nausea, vomiting, and diarrhea; Caused by PG synthesis which is promoted by E2 followed by P4.
What do Prostaglandins released in menses cause?
Uterine contractions; may be severe enough to cause ischemia and pain
Causes dysmenorrhea
(single most common cause of female work/school absenteeism, treated with oral contraceptives and PG synthesis inhibitors)
Premenstrual syndrome and premenstrual dysphoric disorder
- when does it occur in ovarian cycle?
- what is the result?
- how is it treated
Occurs in late luteal phase
Both physical and behavioral symptoms that interfere with normal life; very normal (this is PMS, so irritability, bloating, etc)
Treated with SSRi’s and oral contraceptives to suppress ovulation
Hirsutism
- What is it?
- Common causes
Inappropriate heavy hair growth in androgen sensitive areas
Excessive androgen production by adrenals (ex. adrenal hyperplasia or Cushing Syndrome) or intake of exogenous androgens and idiopathic increases in sensitivity to androgens
Common symptom of PCOS
Virilization
Includes hirsutism and more pronounced evidence of androgen stimulation such as clitoral hypertrophy, deepening voice, temporal balding, male pattern skeletal muscle development (excess androgen production is a big cause)
PCOS
- What causes it?
- What is the result of this? Including: Weight management, and what’s going on with the generation of those ovarian cysts?
Root cause - insulin resistance and obesity (caused by and causes OF PCOS)
High insulin –> high androgen production –> causes infertility
in addition:Increase in conversion of estrogens due to excess androgens, which leads to excessed weight gain
Follicle development is imaired; ovulation is not completed and follicles degenerate into cysts. Overall, ovary doubles in size.
Symptoms of PCOS
Sleep apnea, menstrual irregularity, acne, besity, decreased HDL and increased TGs, hirsutism
Treatments for PCOS
Weight loss, cessation of smoking, metformin (insulin release) - metformin alone is often sufficient to restore fertility.
Clomiphene which helps induce ovulation is also helpful in PCOS cases
menopause
Age related cessation of ovulation (happens between 48-52)
How do you know you’re entering menopause? What are the hormone sensitivity problems?
Onset frequency of anovulatory bleeding increases and cycles become irregular with gradual diminution of menstrual flow. Sensitivity of follicles to FSH ad LH declines; follicles disappear, ovarian generation of estrogens drop and maintain of lower generations of steroids depend on peripheral conversion of androgen precursors secreted by adrenal glands.
After menopause, what is the dominant estrogen?
Estrone
Loss of negative feedback from estradiol and inhibin causes what?
3-4x increase in FSH + LH with FSH being greater than LH due to slower GnRH pulsitility; this ratio remains in absence of cyclicity of the ovarian cycle.
Symptoms and consequences of menopause (5)
- Osteoporosis (increase in bone resorption due to less OPG activation from less estradiol and less bone formation)
- CV disease risk goes up - increase in cholesterol, LDL, and decrease in LDL receptors (increase in risk of atherosclerosis
- Thinning of vaginal epithelium and decreased secretions
- decreased breast mass
- vascular flushing (hot flashes) due to CNS mediated changes in GnRH
HRT and post menopausal women - set up of experiment, results?
Two paradigms: Women given conjugated equine estrogen alone OR horse estrogen and progestins (if uterus present)
Found that there was a greater risk of CV, venous thromboembolism, breast cancer, fracture, colorectal cancer, etc. However, later studies have called this into question; particularly becaue many of the women were in later stages of menopause, and people who were in perimenopause had very beneficial outcomes, wehreas those who had it later had negative outcomes
Timing hypothesis of HRT
There is a window of opportunity - you must give HRT to menopausal women at the right time
What are peak fertility ages
18-25
Where does fertilization occur
in fallopian tube – within 24h after ovulation (12-16 days post previous menses)
how is gestational age calculated
from first day of last menses
What is fetal age
2 weeks less than gestational age
When is the best time to get preggo
24h post ovulation for ovum; 48-72h post coitus
After embryo implatns into endometrium, what special organ is formed?
placenta
What is the function of the placenta
endocrine gland; takes over steroid and protein hormone synthesis to support developing embryo
Symptoms of pregnancy follow what?
placenta formation
Symptoms of pregnancy
Breast tenderness, fatigue, nausea, absence of menstruation, softening of uterus, sustained elevation of body temperature
what is the final stage of gestation?
Parturition
What influences Parturition?
fetal and maternal factors
Gamete transport – how fast do sperm reach ampula and how long do they live
Reach ampulla within 5 mins, retained 24-48 h
50-100 reach this point
What are factors that assist in sperm transport? (5)
1- vaginal secretions become more alkaline
2- uterine contractions and cervical contractions propel sperm forward
3- prostaglandin in seminal plasma induces muscle contractility
4- Seminal “plug” coagulates upon ejaculation
5- vaginal mucus becomes less viscous
How many oocytes are released from ovary into peritoneal cavity
One
At ovulation, what is released into the surrounding peritoneal cavity?
oocyte and the cumulus oophorus
how are sperm and ovum mixed
churning motion of the ampulla wall
Where does fertilization usually occur?
In the ampulla - this is where the first stages of embryonic development occur as well. This is the devleopment of the blastocyst
What is sperm capacitation?
Functional properties of sperm acquired in female tract that allow for penetration of zona pellucid of egg; poorly understood, thought to include removal or modification of protein coat covering sperm and may involve vagina, uterus, cervix. It makes sperm competent to undergo acrosomal reaction.
Acrosomal reaction (3)
- Sperm binds to ZP3 protein on zona pellucida (glycoprotein)
- Triggers increased calcium in sperm cell - leads to exocytosis of hydrolytic enzymes
- Sperm and oocyte membranes fuse - acrosome reacted sperm bind to ZP2 proteins
Cortical reaction
Spermatozoon penetration then triggers calcium increase in oocyte, resulting in fusion of cortical granules with plasma membrane. This releases enzymes that harden glycoproteins of zona pellucida This is including exocytosis of sperm internal contents and exocytosis of oocyte’s internal vesicles. The same increase in calcium that triggers the cortical reaction also triggers the end of meiosis II – then the second polar body is released, leaving oocyte with haploid, unduplicated chromosomes. Fusion with male pronucleus leads to zygote formation.