Male and female reproductive endocrinology Flashcards
Male sex hormones
Androgens
FSH on testes
Causes sperm production
Testosterone secretion stimulated by
LH
Effects of oestrogens on the foetus
No effects
Secretion of testosterone in the embryo effects
Development of male foetal anatomy
Default situation in embryology
Female anatomy
No hormones will result in female anatomy
Androgens causes male anatomy
If XY embryo cannot produce testosterone
He will be born with female internal and external anatomy
Effects of testosterone in puberty
Secretion increases
Increased aggression and libido
Enlargement of the larynx
Male pattern pubic hair
Maturation of genitalia
Muscle development
Sperm production
Bone growth
Acne
Hormones that cause the ovaries to secrete oestrogen and progesgterone
FSH
LH
Progesterone
Steroid
Only important in pregnancy
Progestogens
Synthetic hormones used in contraceptives
Progesterone like hormones
Negative feedback of oestrogen and progesterone
Progesterone suppresses LH secretion
Oestrogen suppresses FSH secretion
What hormone is every foetus exposed to?
Oestrogens
Oestrogen increase in puberty in females causes
Bone growth
Female psyche
Fair complexion
Breast development
Widening of the pelvis
Maturation of genitalia
Female pattern pubic hair
Subcutaneous fat deposition
Average length of menstrual cycle
28 days
Female foetus exposed to androgens
Loses pulsitility of GnRH
Becomes like a male
Menopause causes
Due to the stopped secretion of oestrogen
First day of the menstrual cycle
First day of bleeding
During menstruation
FSH starts to rise
Oestrogens start to rise
Oestrogens have negative feedback over FSH so start to dip
About day 12
Surge in LH secretion
Also a small surge in FSH (accidental)
Signal for LH surge requires 36 hours of elevated oestrodiol
About day 15
LH surge caused progesterone and oestrodiol secretion
Progesterone and oestrodiol rise
For about 7 days
Start to drop again by day 28
Units of oestrodiol and progesterone
Oestrodiol up to 2 nmol/l
Progesterone up to 50 nmol/l
First half of cycle oestrodiol dominated
Second half of cycle progesterone dominated
Actions of testosterone mid cycle in women
Acne
FSH causes follicle to
Mature
Ovum moves to edge of follicle
LH surge causes
Ovum to be expelled follicle
Day of ovulation
14 days before the first day of menstruation
Oestrodiol on the endometrium of the uterus
Causes it to thicken
More oestrodiol for longer, the endometrium would carry on thickening
Progesterone on the endometrium of the uterus
Growth of the endometrium stops
Starts to secrete nutrients
Purpose of secretory phase to allow the ovum to grow
Ovulation does not result in conception
After 7 days the secretion of oestrodiol and progesterone declines
Endometrium without stimulatory hormones
Collapses
Any drop in progesterone
Triggers collapse of the endometrium
Even with small drop
Drop in progesterone and blood vessels
Causes the blood vessels in the endometrium to constrict
Tissue deprived on blood supply so lack of oxygen and nutrients leads to atrophy
Causes bleeding as tissues are dying
After constriction of blood vessels
After a few hours they suddenly dilate
Surrounding tissue is dead
Increased blood supply washing off dead cells (around day 26/27)
Blood clots on the top of the endometrium
Fibrinolysis
Blood clot breaks down after a few days
Results in liquified clot
Menstruation
Loss of liquified blood clot
Anoxic cells and pain
Produce inflammatory mediators such as prostaglandins
Cause uterine contraction- menstrual cramps
Drugs that inhibit prostaglandin synthesis
NSAIDs
e.g. aspirin
Good at preventing period pain
Effects of aspirin
Prevents period pain
Anticoagulant so could cause increase menstrual flow- NO EVIDENCE (theoretical risk)
Function of cervix
Prevents bacteria from going from the vagina into the uterus
Cervix under the influence of oestrogens
Massively dilates
At the time of ovulation
Cervix under the influence of progesterones
Constricts
Cervix under the influence of prostaglandins
Dilates
Allows menstrual flow
Influence of oestrodiol on cervix
Makes mucus very running
Bacteria can’t get through but sperm can swim so they can
Progesterone and mucus
Makes it thick and gooey
Sperm and bacteria cannot get through
Progesterone and body temperature
Increase by about 0.5’C
The day it goes up is the day after ovulation
Life expectancy of the ovum
36-48 hours
Sperm life expectancy
Active life span of about 2 days
Inhibin in females
Increases at the time of the LH surge
Used to measure reproductive health
Women with low day 3 inhibin concentration less likely to respond to IVF
