Female reproductive physiology Flashcards
what organs does the female reproductive system involve?
- 2 ovaries
- 2 fallopian tubes
- 1 uterus
- cervix
- vagina
what is the lower portion of the uterus called?
the cervix
what is puberty?
the period which the reproductive organs mature and reproduction becomes possible
why does puberty occur earlier now than before?
- healthier environment
- perfect nutrition
what are the main female sex hormones?
- oestrogen
- progesterone
what is estradiol (form of oestrogen) & what is it important for?
- estradiol is the major ovarian steroid sex hormone
- essential for the development of secondary sex characteristics such as increases in bone density, breat development etc
what are the phases of the menstrual cycle?
- menstruation
- follicular phase
- ovulation
- luteal phase
what is the follicular phase?
- longest phase of the menstrual cycle
- the follicles in the ovary mature from a primary follicle to a fully mature follicle
what is the luteal phase?
WHAT IS IT CHARACTERISED BY?
- fixed at around 14 days long
- characterised by **changes in hormone levels **- such as increases progesterone & estrogen levels and a decrease in FSH and LH
- there is also** changes to the endometrial lining** of the uterus in order to potentially implant a fertilised egg
- The corpus luteum also develops
what are the main hormones involved in the hypothalamic pituitary ovarian axis?
what are they and what secretes them?
- GnRH released by the hypothalamus
- FSH and LH released by the anterior pituitry gland
- oestrogen, progesterone & inhibin released by ovaries
Describe te secretion of FSH during the menstrual cycle
- FSH increases in the early follicular phase, and then steadily decreases throughout the remainder of the cycle
Describe LH secretion during the menstrual cycle
- LH is constant during most of the follicular phase
- it then shows a big peak called the LH surge just before ovulation
- it then decreases during the luteal phase
what is ovulation?
- the expulsion of a mature oocyte to the abdominal cavity and is collected by a trumpet shaped distal end of the uterine tube - triggered by LH surge
Describe oestrogen during the menstrual cycle
- oestrogen concentration increases rapidly during the 2nd week of the menstural cycle
- it then starts to decline just before the LH surge
- after that there is a second increase as the corpus luteum secretes it
- then there is a rapid decrease during the final days of the cycle
Describe progesterone secretion during the menstural cycle
- small amounts of progesterone are released during the follicular phase
- the corpus luteum begins to release progesterone and the pattern is then similiar to oestrogen
what are the functions of oestrogen?
- development of secondary sex characteristics
- fertility
- increases fallopian tube motility (contractions) uterine contraction
- stimulates endometrial growth
why is an increase in fallopian tube contractions / female reproductive organ contractions important for sperm motility?
the contractions help to push the sperm forward
what are the functions of progesterone?
- decreases uterine contractions
- decreases cervical/ vaginal actions and therefore decreases sperm motility
- inhibits milk let down
- important for the maintenance of the pregnant state
what hormones inhibit and stimulate milk let down?
- prolactin stimulates milk let down
- progesterone inhibits milk let down
what are the several functions of the ovary?
- oogenesis - production of female gametes
- maturation of the oocyte
- expulsion of the mature oocyte (ovulation)
- secretion of the female sex hormones - oestrogen, progesterone & inhibin
what is a ovarian follicle?
- they are the basic functioning unit of an ovary
- each one contains an oocyte
what is an oocyte?
a female germ cell that gives rise to an ovum (egg)
what are the 2 endocrine cells of the ovary?
- theca cells
- granulosa cells
what are the theca cells (ie what are the 2 layers and what is their function?)
- 2 layers - theca externa and theca interna
- they synthesise androgen called androstenedione in response to LH
- they are indirectly involved in the production of estradiol (E2)
what are the granulosa cells & what is their function?
- endocrine cells of the ovary
- They produce estradiol in response to FSH but** only if the theca cells produce androgens in response to LH**
what is the primary type of follicle?
primordial follicles - consist of 1 primary oocyte surrounded by a single layer of cells called granulosa cells
what does the primordial/primary follicle develop into?
- secondary follicles
- this is characterised by an increase in size of the oocyte
- proliferation of the granulosa cells into multiple layers
what do the secondary follicles develop into ?
& what are the distinctive characteristics?
- tertiary follicles
- characterised by proliferation of the granulosa cells and differentiation into different layers called theca cells
- the primary oocyte reaches its full size and is surrounded by a fluid filled space called an antrum
what is a mature oocyte called?
a graafian follicle
what is the corpus leteum?
- a temporary endocrine structure within the ovary
- forms at the site of a follicle in the ovary that has released its ovum
- secretes progesterone, oestrogen and inhibin
what is the difference between granulosa cells and theca cells?
- Granulosa lutein cells are closest to the central connective tissue core of the corpus luteum and produce progesterone. .. also secrete estrogen
- Theca lutein cells are smaller cells than the former with** dark-staining nuclei**. These cells produce estrogen and are located peripherally between the folds of the granulosa lutein cells.
what is ovotesticular disorder of sex development?
- when an infant is born with the internal reproductive glands of both sexes (female ovaries & male testes)
- 46 XX
what is female psuedohermaphroditism?
- a female has matching chromosomal and gonadal tissue sex but mismatching external genitalia
- clitorial hypertrophy is present
what is the main cause of female pseudohermaphroditism?
- congenital adrenal hyperplasia (enlargement of the adrenal gland)
- excessive production of androgens
what is male pseudohermaphroditsm?
- matching chromosomal and gonadal sex tissue but mismatching external genitalia
what is the main cause of male psuedohermaphroditism?
- inadequate production of testosterone and AMH (anti-mullarian hormone)
what is androgen insensitivity syndrome?
- when an individual has testes but female appearance including breasts
- there is no mensturation and no pubic hair
what is the cause of androgen insensitivity syndrome?
- a genetic defect on X chromosome resulting in resistance to the action of testosterone in the fetus - therefore masculisation is inhibited
what is 5 alpha reducatse deficiency?
- an inherited autosomal recessive disorder
- mutation in the SRD5A2 gene enoding 5 alpha reductase
- a lack of 5AR means a lack of the conversion of testosteroe into dihydrotesosterone
what are the characteristics of 5 alpha reducatse deficiency?
- female external genitalia
- micro penis
- decreased male fertility
Describe natural contraception
- 80% effectivity
- no side effects
- requires a daily record of temperature and mucous secretion
- temperature drops before ovulation
- can only be used by women who have a regular cycle
Describe the 2 forms of oral contraception
- combined oral contraception - the pill - contains both estradiol and progesterone, 99% effective, prevents ovulation
- progesterone only pill - ie the mini pill, prevents ovulation, and prevents sperm getting through the cervix and prevents an egg from implanting, 99% effective
what are the advantages of 17b - estradiol (E2) versus ethinylestradiol?
- less negative impact on liver metabolism
- higher protective effect in rgard to osteoporosis
- higher positive effects on skin, vaginal epithelium and connective tissue
what is emergency contraception?
what are the different types
- morning after pill
- progesterone - effective up to 72 hours after intercourse
- ullipristol ECF - effective up to 5 days after intercourse - from GP
what is an IUD?
- T shaped device
- contains either copper or levonorgestrel (progesterone)
- inserted into the uterus
- lasts for 3 years / 5 years
