Reproductive - Physiology Flashcards
In the hypothalamic pituitary gonadal axis, what is released from the hypothalamus?
GnRH
In the hypothalamic pituitary gonadal axis, what is released from the pituitary gland?
LH and FSH
In males, where does LH exert its action? What effect does it have?
It acts on the Leydig cells of the testes to stimulate testosterone production
What are some actions of testosterone in males?
Anabolism, male secondary sexual characteristics, maintenance of libido
When testosterone is produced by the testes, it acts locally to aid with what process?
Spermatogenesis
Testosterone exerts negative feedback on which hormones involved in the hypothalamic pituitary gonadal axis?
GnRH, LH and FSH
In males, where does FSH exert its action? What effect does it have?
It acts on the Sertoli cells of the testes to produce mature sperm
Inhibin exerts negative feedback on which hormones involves in the hypothalamic pituitary gonadal axis?
FSH
What is the action of activin?
To counteract inhibin, and promote secretion of FSH
What is the average duration of the menstrual cycle?
28 days
How often is GnRH produced?
2 hourly intervals
In females, where does LH exert its action? What effect does it have?
It acts on the theca cells of the ovary to stimulate androgen production
In females, where does FSH exert its action? What effect does it have?
It acts on the granulosa cells of the ovary to stimulate follicular development and activity of aromatase
In both males and females, the action of FSH also results in the production of what hormone?
Inhibin
What is the role of aromatase?
To convert ovarian androgens into oestrogen
The mechanisms initiating puberty are thought to result from what?
Withdrawal of central inhibition of GnRH release
What peptide is believed to play a crucial role in the regulation of GnRH production and the timing of puberty?
Kisspeptin
LH and FSH are both low in the pre-pubertal child. In early puberty, which begins to rise first?
FSH
What is the average age of puberty onset in males?
12 years
What is the first sign of puberty to develop in males?
Enlargement of the testes
A boy has officially entered puberty when the testicular volume reaches what?
4ml
What is the average age of puberty onset in females?
11 years
What is the first sign of puberty to develop in females?
Development of breast buds
What is the average age of the onset of menarche in females?
13 years
Menarche usually occurs when in relation to the onset of puberty?
2-3 years later
What days of the menstrual cycle correspond to the follicular phase?
Days 1-13
Day 1 of the menstrual cycle corresponds to what physiological event?
The first day of menstruation
What days of the menstrual cycle correspond to the ovulatory phase?
Day 14
What days of the menstrual cycle correspond to the luteal phase?
Days 15-28
An increase in the level of what hormone stimulates the dominant follicle to develop, and kicks off the follicular phase of the menstrual cycle?
FSH
In response to FSH stimulating the dominant follicle to develop, what hormone is increased from the follicle?
Oestrogen
Increasing oestrogen in the follicular phase of the menstrual cycle leads to a surge in what hormone?
LH
A surge in the level of what hormone in the menstrual cycle leads into the ovulatory phase of the cycle?
LH
After the dominant follicle has ruptured and the remaining granulosa cells become the corpus luteum in the luteal phase of the menstrual cycle, what hormones does the corpus luteum secrete?
Oestrogen and progesterone
The luteal phase of the menstrual cycle always lasts how long?
14 days
In the menstrual cycle, progesterone levels peak when?
7 days after ovulation
Progesterone measured when gives the most reliable answer as to whether a woman has ovulated or not?
7 days before the onset of the next predicted menses (day 21 of an average 28 day cycle)
If implantation does not occur after ovulation, the corpus luteum regresses and the levels of what hormones fall to allow the endometrium to be shed?
Progesterone and inhibin
Reducing levels of progesterone and inhibin once implantation has not occurred after ovulation allows the levels of which hormones to rise in order for the cycle to start again?
GnRH and FSH
If implantation and pregnancy occurs following ovulation, what hormone is produced by the trophoblast to maintain corpus luteum function for 10-12 weeks until the placenta has formed?
HCG
The proliferative phase corresponds to which days of the menstrual cycle?
Days 5-14
In response to the increasing levels of oestrogen produced in the follicular phase, what happens to the endometrium?
It thickens
The secretory phase corresponds to which days of the menstrual cycle?
Days 15-28
What effect does progesterone have on the endometrium in the secretory phase of the menstrual cycle?
Inhibits further proliferation, causes the endometrium to differentiate and mature
The head of the sperm is surrounded by a cap like structure known as what?
Acrosome
The tail of the sperm contains vast amounts of which organelle?
Mitochondria
Only sperm which pass through which anatomical structure are capable of fertilisation?
Epididymis
Spermatozoa are able to fertilise an oocyte for how long after ejaculation?
5 days
Conception can occur if intercourse has occurred at any time within what frame?
The 5 days before ovulation
Where does fertilisation take place?
Ampulla of the Fallopian tube
When spermatozoa reach the cumulus oophorus of the oocyte, their acrosomes release what to break up the cumulus cells and allow them to penetrate the zona pellucida?
Lytic enzymes
Low testosterone or oestradiol with high gonadotrophins indicates there is a problem where in the hypothalamic pituitary gonadal axis?
Gonads
Low testosterone or oestradiol with low or normal gonadotrophins indicates there is a problem where in the hypothalamic pituitary gonadal axis?
Hypothalamus or pituitary gland
During which phase of the menstrual cycle does PMS occur?
Luteal phase
What is the name for a severe form of PMS?
Pre-menstrual dysphoric disorder
What are the pharmacological treatment options for PMS?
SSRI or COCP
What is the average age of onset of the menopause?
51 years
Clinically, when are women described as being post-menopausal?
When they haven’t had a period in over a year, in association with a permanently raised LH/FSH
After the menopause, where is oestrogen still being produced?
Adipose tissue, bones and brain
Large fluctuations in the level of which hormone may be responsible for menopausal symptoms?
GnRH
Urogenital atrophy during/after the menopause can lead to what symptoms?
Dyspareunia, increased risk of infections and stress incontinence
What pharmacological treatment is available for the treatment of hot flushes?
SNRIs e.g. venlafaxine
What are the 2 most significant complications of the menopause?
Decreased bone density and an increased cardiovascular risk
Premature menopause is usually treated with HRT until what age in order to maintain bone health?
50 years
Should women with premature menopause use contraception if they do not want to conceive?
Yes
HRT should only be given for up to how long?
5 years
Combined HRT should be given to which women?
Post-menopausal women with an intact uterus
Cyclical HRT should be given to which women?
Women with menopausal symptoms who are still menstruating
What treatments are useful for treating symptoms of urogenital atrophy?
Oestrogen pessaries or creams
HRT increases the risk of which malignancies?
Breast and endometrial
Why should women who have a uterus not be given oestrogen only HRT?
To reduce the risk of endometrial cancer
What HRT regimen should be offered to women with a previous history or increased risk of VTE?
Transdermal HRT
