E4 Female reproductive system Flashcards
functions of female reproductive tracts
- production of ova (oogenesis)
- reception of sperm
- transport of the sperm and ovum to common site for union (fertilisation / conception)
- maintenance of the developing foetus until it can survive in the outside world
- giving birth
- nourishing the infant after birth
medical term for giving birth
parturition
medical term for breastfeeding
lactation
primary female reproductive organs
- ovaries
- uterus
- oviducts (fallopian tubes)
- vagina
- vulva
- clitoris
- mammary glands
- pelvis (has a role in delivering foetus)
label the image
describe the ovary
- originate from the same germ cell as male testes based on X or Y second chromosome
- contain: primary follicles and Graafian follicles
- produces ova
- made of outer cortex and central medulla
- contain all the sex cells they will ever have at birth
describe primary follicles that are contained in the ovaries of the female reproductive system
germ cells and granulosa cells
describe Graafian follicles that are contained in the ovaries of the female reproductive system
germ cells, granulose cells and theca cells
describe the oviducts
- fallopian tubes
- collects released ova and serves as the site of fertilisation
- transports fertilised egg to uterus to be embedded
- ciliated, glandular and has epithelial lining
describe the uterus
- thick-walled hollow comprised of the endometrium (inside layer) and myometrium (outside muscle layer which drives contractions in labour)
- responsible for maintaining the foetus during pregnancy
describe the cervix and cervical canal
- lower section of the uterus with exit into the vagina
- mucus plug maintains barrier into cervix to prevent bacteria getting into uterus from vagina (must be opened during vaginal birth)
- narrow sphincter of smooth muscle tissue holds foetus inside the uterus to make sure the foetus is maintained and supported during pregnancy
describe the vagina
- a muscular tube connecting uterus to external environment
- repository for sperm during intercourse
how long do oocytes take to develop and mature in the ovary before being released?
more than 300 days
function of the cilia in the oviducts
encourage movement of ovum into the uterus by wafting
what do uterine glands do?
secrete certain hormones to drive changes during the menstrual cycle and during labour
before a baby is born (at around 7 months) what happens to the oogonium in the foetus? describe oogenesis
- undergoes meiosis I and only completes this division at puberty (held in mid-divisional stage until puberty)
- meiosis II occurs after fertilisation and produces 1 egg cell and 3 polar bodies which are destroyed
- the process whereby primary oocytes are converted into the mature ovum with associated replication of genetic material
describe what happens to different types of oocytes like when they are released and when they divide
- 1 primary oocyte is chosen to be released during ovulation after undergoing cell division
- secondary oocyte will only divide into mature ovum after it has been fertilised
describe the development of follicles and what happens to them afterwards
- primary follicles develop into larger secondary follicles (oocyte granuloma cells and theca cells)
they can then:
- die (atresis)
- remain arrested in the pre-astral phase (13-50 years)
- grow into a Graafian / mature / antral follicle
describe the basis of selection of follicles
- unknown
- occurs once a month
- thought to involve FSH
what is the conversion of secondary follicles to Graafian follicles under the control of?
3 hormones
- LH
- FSH
- oestradiol
what is the conversion of secondary follicles to Graafian follicles associated with?
proliferation of granulosa and theca cells and development of a fluid-filled space (the Antrum)
describe how LH controls the Graafian follicle phase
- stimulates 20,22 desmolase activity in theca cells and testosterone production
- there is a small amount of testosterone and there is involvement of progesterone (this is what leads to the testosterone)
describe how FSH controls the Graafian follicle phase
- stimulates the granulose cells of the follicles
- aromatase activity which in turn produces estradiol from testosterone
- LH receptors in preparation for LH surge
- FSH also causes an increase in LH receptors on theca cells
describe how oestradiol controls the Graafian follicle phase
- causes proliferation of granulose cells and gives rise to oestrogen
- oestrogen is very important for the first phase of the menstrual cycle
compare oogenesis and spermatogenesis
- not all primordial germ cels undergo full oogenesis
- fixed number of oocytes at birth which diminishes during life (only 400 successfully released)
- first meiotic division of oocyte occurs after release from the ovary, second meiotic division is triggered upon entry of sperm (fertilisation)
- hormone levels vary throughout the month whereas with testosterone it is a constant level that is maintained all the time
describe ovulation
- Graafian follicle migrates to surface of ovary and ruptures to release secondary oocyte into fallopian tube under the influence of LH (need LH surge at ovulation)
- primary oocyte undergo first meiotic division to secondary oocyte and polar body just before ovulation
- residual element of follicle forms Corpus Luteum (an endocrine unit that produces its own hormones) which provides balance of gonadal steroids necessary for implantations of fertilised ovum
what are the 2 types of hormones that control female reproduction. state examples of each
steroid hormones
- oestrogens
- progesterones
peptide hormones
- gonadotrophins (FSH and LH)
- human chorionic gonadotrophin (hGC)
- oxytocin
- prolactin
what is hGC the basis of?
basis of early pregnancy tests - it is detected in the urine
what is oxytocin responsible for?
causing contraction in labour (positive feedback loop)
what is prolactin important for?
when woman is lactating after birth of baby
what does hypothalamus produce?
GnRH
what does pituitary produce?
LH and FSH
what hormones do ovaries produce?
oestrogen and progesterone
where is GnRH produced?
hypothalamus
where are LH and FSH produced?
pituitary
what are the 2 basic jobs of a female in reproduction?
- produce a haploid gamete
- support the fetus
how do females produce a haploid gamete and what hormone is involved?
- changes in ovary during 1st half of menstrual cycle (first 14 days)
- oestrogen is the main hormone that drives this
how do females support the foetus and what hormone is involved?
- changes in uterus during second half of menstrual cycle if the ovum is fertilised during the first 14 days
- progesterone
what are LH and FSH produced by and what do they respond to?
- produced by anterior pituitary
- respond to GnRH hormone produced by the hypothalamus
what happens to the granulosa and theca cells before ovulation at 14 days? what happens after this?
- they undergo a period of cell division to lead up to ovulation (release of oocyte for fertilisation)
- cells then undergo recycling process to produce corpus luteum that slowly regenerates
what happens as corpus luteum degrades? what happens after its degradation?
- it releases progesterone
- after this, progesterone level returns to normal for cycle to start again
when does oestrogen need to peak in females?
oestrogen needs to peak at the same time as FSH and at the same time as the LH surge
describe the changes in hormones during the menstrual cycle
- LH surge
- increase in FSH production
- once corpus luteum has completed degradation, progesterone levels drop off
growth and maturation of follicle occurs into different cells. what kind? what else happens?
theca cells
increase in granulosa cell mass
increase in fluid space (antrum)
describe what happens after an oocyte is released in detail
- after oocyte has been released, you get a luteal phase that is driven by a peak in progesterone (released from corpus luteum)
- in the endometrium, there is an increase in vascularisation and after this 14 days there is a secretory phase if there is no fertilisation (endometrium tissue needs to be returned back to normal)
when does GnRH peak?
at ovulation (released in pulsing manner)
describe the pro-ovulatory follicular / proliferative phase
- follicles release oestrogens under basal pulsatile release of FSH and LH (oestrogen production increases because of FSH and Lh increasing)
- anterior pituitary hormones release determined by pulsatile GnRH release
describe how hormone levels change in the pro-ovulatory proliferative phase
- initially oestrogen production increases due to synergy between low levels of FSH and LH which in turn causes negative feedback on further FSH and LH pituitary release
- 200pg/ml oestradiol for more than 2 days causes reversal of feedback control and LH surge
- LH surge stimulates LH receptors on granulosa cells of follicle
other effects outside the ovaries in the follicular / proliferative phase
- thickening of endometrium and vascularisation
- vaginal mucous secretions changes: low thick / low volume to watery / high volume (increases mobility of ovum and increases deposit of sperm and movement)
- cilia in fallopian tubes beat towards uterus (encourage movement of ovum down the fallopian tube towards sperm)
describe some specialisation of the female for sexual reproduction
- production of a nourishing gamete (large cell size with a large cytoplasm)
- specialised anatomy
- quality control and timing (LH surge must watch drive in oestrogen)
- menstrual cycle to support 2 roles
- specialised hormones and positive feedback loops
- behaviour
- secondary characteristics
