Female Reprodictive Anatomy & Physiology Flashcards
What makes up the female reproductive system?
(6 points)
- Gonads (ovaries - gamete production + production of sex hormones)
- Fallopian tubes (carry developing oocytes from ovary to uterus + for sperm transport)
- Uterus (house + support growth of embryo/foetus)
- Cervix (allows passage of sperm)
- Vagina
- Vulva (external genitalia)
Where does fertilisation take place?
Fallopian tubes
What does the vulva comprise of?
(4 points)
- Mons pubis (layer of fatty tissue overlying pubic bone)
- Labia (labia majora/minora)
- Urethral meatus (opening)
- Clitoris
What 2 hormones are produced by the ovaries?
Oestrogen
Progesterone
What connective tissue surrounds the ovaries?
Tunica albuginea
What does the main ovary comprise of?
- Outer cortex (primordial follicles)
- Central medulla (connective tissue + blood vessels)
- Inner hilum
What is the role of the fallopian tubes?
- Carries ovum from ovary
- Facilitates sperm movement
How is the movement of oocytes through the fallopian tubes aided?
- Fimbria (cilia-covered, fringe-liked stucture that sweeps ovulated ovum into tube)
- Contractions of wall of tubes
What is the uterus surrounded by?
- Peritoneum
- Perimetrium
What 2 muscles are in the uterus?
- Myometrium (smooth muscle + vascular tissue)
- Endometrium (inner cavity)
What is the role of the uterine glands?
Provide nourishment (proteins) for embryo until placenta is established
What happens during the oestrous cycle?
Pro-oestrus:
- Follicle start developing
- Secretes oestrogen
- Endometrium develops
Oestrus:
- In heat
- Female is sexually receptive/ready for mating
- Might be visible through various signs, e.g. reddening of labia
Metoestrus:
- Lutueal phase
- Corpus luteum develops from ruptured follicle after ovulation
Dioestrus:
- Corpus luteum produces progesterone
- Prepares uterus for implantation
- In the absence of pregnancy, corpus luteum degenerates
- Endometrium is reabsorbed for next cycle
Anoestrus:
- Sexual inactivity
- Induced by pregnancy, lactation, illness, age & seasons/time of the year in seasonal breeders
- In seasonal breeders, it is controlled through exposure to light that influences the release of melatonin from pineal glands
Give 2 examples of other animals that have a menstrual cycle
- Elephant shrew
- Spiny mouse
What happens to those species with an oestrous cycle rather than a menstrual cycle?
Endometrium is reabsorbed
What is a duplex uterus?
2 distinct uteri (open separately into vagina)
What is a bipartite uterus?
Partial septum separating uteri
What is a bicornuate uterus?
No septum
What is the cervix?
- The narrow, lower portion of uterus
- Soft with an abundant, thin, mucus secretion just before ovulation (to facilitate sperm movement)
What happens to the cervix after ovulation?
- Closes up
- Becomes harder
- Cervical secretions are thicker + stickier
What is the role of the vagina?
- Muscular tube for receiving male penis
- Provides passage of foetus at parturition
What is the role of the Bartholin’s glands + where are they?
- Secrete mucous to lubricate vagina
- Lie slightly posterior + to left/right of vaginal opening
What 2 phases does the menstural cycle consist of?
- Follicular phase
- Luteal phase
What happens in the follicular phase?
- Hypothalamus secretes GnRH
- GnRH acts on anterior pituitary gland to secrete FSH & LH
- FSH stimulates follicles in ovary
- Oestrogen secreted from granulosa cells in ovary
- Oestrogen will thicken endometrium & thin cervical mucous to prepare for fertilisation
- Oestrogen acts in a negative feedback loop on the hypothalamus so that FSH isn’t continuously released & only 1 dominant follicle continues developing
- LH released for ovulation at day 14
What happens in the luteal phase?
- Corpus luteum produces progesterone + oestrogen
- Progesterone will thicken endometrium & thin cervical mucous for fertilisation
- Oestrogen & progesterone acts in a negative feedback loop to reduce FSH & LH
If fertilisation occurs:
- HCG is released from early embryo
- HCG maintains corpus luteum
- Progesterone & oestrogen remain high to support pregnancy
- LH & FSH remain low to prevent further ovulation
- At 6 weeks, placenta takes over oestrogen & progesterone
- Corpus luteum degenerates
If fertilisation doesn’t occur:
- No HCG
- Corpus luteum degenerates
- Decreased oestrogen + progesterone
- Break down of endometrium
- No negative feedback loop so FSH & LH increase
- Cycle stars again
What does high oestrogen cause prior to ovulation?
- Thickens endometrium
- Thins cervical mucous
When does the endometrium develop in the menstrual cycle?
- First 4 days
- In follicular phase, under the influence of oestrogen
What happens within the last 4 days of the menstrual cycle?
- Endometrium disintegrates
- Bleeding occurs from ruptured blood vessels in endometrium
- Blood + disintegrating outer layers of endometrium expelled as menstrual fluid
Describe the development of the endometrium throughout the menstrual cycle
Follicular phase:
- High oestrogen thickens endometrium
Luteal Phase:
- High oestrogen/progesterone from corpus luteum thicken endometrium
- If fertilisation doesn’t occur, corpus luteum degenerates
- Progesterone/oestrogen decrease
- Endometrium breaks down = menstrual bleeding
In non-human mammals, what 4 phases are part of the oestrous cycle?
1- Oestrus
2- Metoestrus
3- Dioestrus
4- Prooestrus
What is the oestrus phase?
- In heat
- Female is sexually receptive/ready for mating
- Might be visible through various signs, e.g. reddening of labia
What are induced ovulations? Give an example.
Ovulation is induced by mating
E.g. cats, camels, llamas, etc.
What is the metoestrus phase?
- Lutueal phase
- Corpus luteum develops from ruptured follicle after ovulation
What is the dioestrus phase?
- Corpus luteum produces progesterone
- Prepares uterus for implantation
- In the absence of pregnancy, corpus luteum degenerates
- Endometrium is reabsorbed for next
What is the pro-oestrus phase?
Pro-oestrus:
- Follicle start developing
- Secretes oestrogen
- Endometrium develops
What is the anoestrus phase?
- Sexual inactivity
- Induced by pregnancy, lactation, illness, age & seasons/time of the year in seasonal breeders
- In seasonal breeders, it is controlled through exposure to light that influences the release of melatonin from pineal glands
What is an ectopic pregnancy?
A complication in pregnancy in which embryo attaches/implants outside uterus, most often in fallopian tubes
What are some symptoms of ectopic pregnancies?
- Cramping
- Abdominal pain
- Vaginal bleeding
What are the outcomes of ectopic pregnancies?
- Uterine tube not large enough
- Lack of blood supply for placenta
- Death of embryo
What is amenorrhoea?
Failure to menstruate normally between puberty + menopause
What is primary amenorrhoea?
If not started by 16 years old
What is secondary amenorrhoea?
If no period for >3 months (outside of contraception, pregnancy, or lactation)
What is amenorrhoea caused by?
- Chromosomal abnormalities
- Hormone imbalance
- Excessive exercise
What is dysmenorrhoea?
Period pains
What is hypogonadism in females?
Under activity, development failure, or absence of ovaries, leading to low levels of female sex hormones
What can cause hypogonadism?
- Chromosomal abnormality
- Abnormality of pituitary gland or hypothalamus
How can hypogonadism be treated?
- Human growth hormone injections
- Oestrogen injections (HRT)
Give an example of delayed fertilisation.
Bats:
- Copulation may occur at any time, most often before winter hibernation
- Sperm kept nourished by uterine secretions for at least 200 days + females ovulate at a time favourable to gestation + birth
- Adaptation to winter dormancy
Give an example of delayed implantation
Bears:
- Zygote undergoes normal cleavage but then blastocyst development is arrested
- blastocyst remains in ‘dormant’ state + doesn’t implant but floats freely in uterus
- Likely an adaptation to facilitate diving birth at optimal time of year
Give an example of a species showing some unusual female adaptations.
Spotted hyenas:
- Sex roles reversed —> f larger + more aggressive than m
- Dominant social group
- F genitals look more like a penis but it is actually the clitoris (vaginal canal turns back on itself and exits the body)
- Also pass high levels of androgens to offspring that make cubs more aggressive + sexually vigorous
Give 4 differences between the menstrual cycle & oestrus cycle
- MS occurs in primates, OS in non-primates
- Endometrium shed in MS, reabsorbed in OS
- F sexually active throughout MS, f only sexually active during oestrus phase in OS
- Ovulation is concealed in MS, visible physiological & behavioural changes in OS
