rda repro Flashcards
- Describe the testis and their function
a. Contain seminiferous tubules which produce sperm (sertoli cells)
i. Prove nutritional and hormonal support for spermatogenesis
b. Contain Leydig cells which produce testosterone and some other androgens
i. Released into circulation to have an effect elsewhere in the body
- What is the epididymis and what does it do
a. Sperm is released from the testis and stored here prior to ejaculation
- What happens during ejaculation
a. Sperm passes through the two vas deferens which are contractile and are mixed with fluid from the seminal vesicles
b. Fluid leaves ejaculatory duct -> urethra -> mix with secretions from prostate gland
- What are the main stages in the maturation of an oocyte
a. Gonadatrophin independent growth
i. Primordial follicle pool
ii. Primordial follicles
iii. Preantral follicle
iv. ALL CAN GO TO ATRESIA
b. Gonadotrophin dependent growth
i. Small antral follicle
ii. Large antral follicle
1) These two above can go to atresia
iii. Preovulatory follicle
iv. Ruptured follicle
v. Corpus luteum
vi. Regressing corpus luteum
- What do thecal cells do
a. Produce estrogens
- What do granulosa-luteal cells do
Produce estrogens and progesterone during the second half of the ovarian cycle
What are the stages of the ovarian cycle and what is the hormonal control
a. Follicular phase
i. FSH induces growth of ovarian follicle
ii. FSH + LH stimulate thecal and granulosa cells to make 17b oestradiol
iii. Follicles continue to grow producing more and more oestrogen which eventually causes an LH surge for ovulation
b. Luteal phase
i. Corpus luteum produces progesterone and oestrogen
What is the regulation of hormones in females throughout the menstrual cycle?
- Follicular phase (early and mid)
i. GnRH -> LH + FSH –> Oestrogens + Progesterone
ii. Oestrogen has a negative feedback effect on pituitary and hypothalamus- Late follicular phase
i. GnRH -> LH + FSH –> Oestrogen and progesterone
ii. Oestrogen has a positive feedback effect to induce a surge of LH to induce ovulation - Luteal phase
i. GnRH -> LH + FSH –> Oestrogens + Progesterone
ii. More progesterone produced than oestrogen but both rise
Oestrogen and progesterone have a negative feedback effect on pituitary and hypothalamus
- Late follicular phase
Describe gametogenesis in males
a. Germ cells
b. Spermatogonium near basement membrane (44 + XY)
c. Mitotic division
d. Primary spermatocyte (44+XY)
e. 1st meiotic division
f. Secondary spermatocytes (22 + X/Y)
g. 2nd meiotic division
h. Spermatids (22 + X/Y)
i. Spermatozoa (22 + X/Y)
j. Released into lumen of seminiferous tubules
Describe gametogenesis in females
a. Oogonia (44+Xx)
b. Mitotic division
c. Primary oocytes (44 + XX)
d. 1st meiotic division (halts and resumes slowly at puberty)
e. Secondary oocyte + 1st polar body (44+XX)
f. 2nd meiotic division stopped in metaphase
g. Resumed at fertilisation
h. Oocyte-> secondary oocyte takes 3 months roughly
What is the process of fertilisation
- Deposition of sperm in female following sexual intercourse
- Sperm deposited near cervix
- Cervical mucus is normally hostile to sperm but changes mid cycle to permit sperm to enter
- Sperm through uterus where capacitation takes place which is essential preparation before sperm meets oocyte
- To fallopian tube to ampulla
- Survival of the fittest
- Egg meets sperm
- Fusion of egg with one sperm within 24 hours post ovulation
- Acrosome reaction = penetration of zona pellucida and coronal cells
- Calcium flux
- Resumption of meiosis to form pronucleus, release of 2nd polar body
- Head of sperm is undergoing decondensation
- Alignment of maternal and paternal chromosomes to generate zygote- dna material in each pronuclei has been duplicated ready for mitotic division
- Cortical reaction = Change in zona pellucida to prevent additional sperm fusing with zygote. Hardening and inactivation of sperm receptors
- Initiation of mitotic divisions in embryo
What is a maternal risk at delivery?
- Spiral arteries can lose relatively large volumes of blood
- Should be limited by contraction of uterus after placenta has been delivered but not always so needs drugs
- Placenta must be fully delivered to ensure the uterus contracts properly to stop blood flow through the spiral arteries
What is the point of viability
- End of second trimester (26-27 weeks) is absolute limit of infant survival in absence of modern neonatal intensive care
- With modern NICU, absolute limit is 22 weeks, 50% survival at 25 weeks
What are the changes in the immune system
- Number of factors that suppress maternal immune system are produced at utero-placental interface
a. Dec Th1 response
b. Inc Th2 system- Placenta expresses unusual HLA which are v polymorphic (HLA-G)
a. Simple structure to signal that is it human so not classified as non self
b. Can suppress activity of leukocytes and down regulate immune system in uterus
- Placenta expresses unusual HLA which are v polymorphic (HLA-G)
What are the maternal changes during pregnancy?
- Inc weight
a. Fetus, amniotic fluid, placenta, inc fluid retention, inc nutritonal stores
b. Mostly 2nd and 3rd trimester- Inc hormone levels
- Inc blood clotting tendency
a. Protective against losing blood at delivery
b. May also be interaction between mum and placenta - Dec blood pressure
- Inc body temp
a. Due to progesterone - Inc breast size
- Inc vaginal mucus production- should be clear
- Inc nausea and vomiting
- Altered brain function
- Altered appetite
a. Uterus imposes pressure on GI system which can dec distenisibility of stomach so smaller meals - Altered fluid balance and urination frequency
a. Higher plasma volume to inc water retention - Altered emotional state
- Altered joints (pelvis)
- Altered immune system (so that fetus is not rejected)
