Reproductive system Flashcards
what is the difference between male and female mitosis ?
male have the parent cell -> gametes cycle during all their life. For female, it is mostly during fetal life : production of mature oocytes ends at birth, and then after puberty some follicles grow each month
how do the ovaries receive blood flow ?
from 2 directions : from the pelvis and the uterus
what are the different phases of the menstrual cycle ? Which one is constant ?
follicular - ovulation - luteal (constant, around 12 days).
Older women are more likely to have a shorter cycle
GnRH : type of hormone, how is it produced and where, how is it secreted, what does it stimulate, how are the neurons that activate GnRH called
- oligopeptide (10 amino acids)
- neural cells produce it in the hypothalamus
- secreted in a pulsatile way in the anterior pituitary
- stimulates secretion of LH, FSH, and HCG
- kiss neurons
LH and FSH : half life, main roles and when are they secreted during the cycle
FSH :
- 3-4 hours half life
- stimulated production and development of follicles during follicular phase -> one becomes dominant
- higher levels in older women
- secretion higher in the first half of the cycle
LH :
- 20-30 min
- induce ovulation and maintain luteal body
- peak secretion right before ovulation
what are present in the two compartments of ovarian follicles
1) theka interna :
- turn cholesterol into androgens
- LH receptors
2) granulosa cells :
- convert androgens into oestrogens (aromatase enzyme)
- FSH receptors (also LH when diameter >12 mm)
how long is the process of ovulation ? what 2 other hormones increase at ovulation ?
takes about 1 hour
oestrogens and progesterone
oestrogens : 3 most important ones, steps in steroidgenesis, action on endometrium
- estriol, estron, estradiol
- cholesterol -> gestagens -> androgens -> estrogens
- stop menstruation and help proliferation of endometrium
gestagens : 2 main hormones, role in general, what happens if fertilization
- progesterone and 17-hydroxyprogesterone
- prepare endometrium for attachment of egg (protrusions called pinopods on the endometrium)
- if fertilization, progesterone increases to support pregnancy
what is the role og HCG in gestation ? (before and after fertilization) When does it start to go down ?
HCG takes over for the maintenance of the luteal body after ovulation. If fertilized egg -> luteal body is named corpus luteum graviditatis. HCG is an indication of the health of the pregnancy.
9 weeks : placenta is formed, HCG concentration starts to go down because placenta takes over.
what is one role of estrogens DURING pregnancy ?
growth of uterus
if the foetus is male, what is the process that impedes male androgens to harm the mother ? how else can circulating androgens be inactivated ?
male androgens (like testosterone) are neutralized by aromatase in the placenta.
Circulating androgens can be inactivated by SHBG (sex hormone binding globulin)
what are 3 signs that the pregnancy reaches the end ?
1) progesterone levels start to drop
2) fetal maturation signaling
3) sterile inflammation
what are the 4 hormones involved in lactation and their main role ?
1) estrogens : proliferation of mammary exocrine tissue
2) progestins : inhibit milk secretion during pregnancy
3) prolactin : stimulate proliferation of mammary tissues
4) oxytocin : expulsion of milk
AMH hormone : where is it secreted, what is its role (male) ?
Secreted by Sertoli cells, in the avascular compartment of the testis (95% of volume of testis).
It inhibits the formation of the Muellerian duct (uterus, fallopian tube, …) -> thus the Wolfian duct is formed.
