hormones in reproduction Flashcards
what happens during puberty (relate to hormones)
reproductive hormones are released which cause secondary sex characteristics to develop
main male reproductive hormone
testosterone
main female reproductive hormone
oestrogen
one egg is released approximately every … days?
every 28 days, in a process called ovulatmion
what are the 4 key processes of the menstrual cycle
1) maturation of egg
2) thickening and maintenance of uterus lining
3) release of an egg from ovary
4) shredding of uterus lining (menstruation) or pregnancy
female secondary sexual characteristics
- hips widen
- pubic/body hair grows
- breast development
- sexual drive develops
- menstruation
male secondary sexual characteristics
- production of sperm begins
- broader shoulders
- voice deepens slightly
- sexual drive develops
sequence of hormones in the menstruation cycle
1) FSH is secreted by the pituitary glands, stimulating the production of oestrogen and causing the eggs to mature
2) oestrogen stimulates the production of FSH and causes the lining of the uterus to thicken. It limits the production of FSH
3) LH stimulates the production of progesterone and it stimulates release of egg at day14( ovulation). production of oestrogen is inhibited.
4) Progesterone is produced from empty follicles and inhibits the production of LH and FSH.
It also maintains the lining of the uterus
What happens when progesterone levels fall
uterus lining sheds
when is the follicular phase
days 1-14
when is the luteal phase
days 14-28
what does FSH stimulate and do
causes eggs to mature
stimulates production of oestrogen
what does oestrogen stimulate and inhibit, and do?
stimulates production of LH
inhibits prod. of FSH
causes uterus lining to thicken
what does LH stimulate and inhibit and do?
stimulates production of progesterone
inhibits production of oestrogen
it stimulates the release of an egg at day 14
what does progesterone inhibit
inhibits production of FSH and LH
what does progesterone do
maintains the lining of the uterus :
allows cycle to restart
OR
allows correct preparation for fertilised egg to implant
where is oestrogen produced
ovaries
where is progesterone produced
empty follicles
name some chemical methods of contraception
-contraceptives
-injections, implants and skin patches
-IUDs
what does contraception do
aims to prevent pregnancy
what are contraceptive pills and what do they do
pills which contain hormones to inhibit progesterone production.
there are two types
what are the two types of contraceptive pills
progesterone only
combination: oestrogen and progesterone
disadvantages of contraceptive pills
you might forget to take it, resulting in pregnancy
lots of side effects
advantages of contraceptive pills
very reliable if taken correctly
what do injections, implants and skin patches do
slowly release progesterone into the blood stream, to inhibit maturation and release of eggs for a number of months or years
disadvantages of injections and implants
must be inserted by a medical professional
advantages of injections and implants and skin patches
lasts for several months
What does an IUD do
prevent the implantation of an embryo or they release a hormone
different types of IUD
plastic IUD
copper IUD
what does a copper IUD do
releases low levels of copper ions which disable sperm cells
what does a plastic IUD do
produces progesterone which stimulates production of a thick mucus lining, preventing sperm from reaching any eggs
advantages of IUD
lasts for several years
disadvantages of an IUD
must be inserted by medical professional and can cause heavy, painful periods
what is sterilisation
-when the oviducts in a woman are cut and tied
-when the sperm ducts in a man are cut and tied
so sperm cannot reach the egg
advantages of sterilisation
permanent and effective, no need to use hormonal or barrier contraception
disadvantages of sterilisation
very difficult to reverse if couple decide to have children
advantages of abstinence during fertile window
no need for hormonal or barrier contraception
disadvantages of abstinence during fertile window
difficult to predict fertile window, so it is unreliable
advantages of a condom/diaphragm
prevents spread of STIs
no need for hormonal contraception
disadvantages of a condom/diaphragm
may break during intercourse, resulting in pregnancy
what is infertility
the long term inability to achieve or maintain a successful pregnancy
what causes infertility
- oviducts are damaged/blocked by infection
- a donor egg needs to be used (pre-mature menopause)
- no obvious cause
- a man produces very few sperm or sperm that doesn’t mature correctly - low motility
what hormones can be taken as a ‘fertility drug’
LH and FSH which trigger ovulation
disadvantages of IVF treatment
- increased likelihood of multiple pregnancies ( twins, triplets etc.), resulting in premature birth
-costly if it is not successful (you would need to do multiple rounds) - emotionally and physically stressful
- could lead to OHS, where too many eggs develop in the ovaries, causing swelling and pain
disadvantages of fertility drugs
a lot of side effects
what does a short pregnancy length mean
baby has a lower weight and the risk of death in birth increases
main steps of IVF treatment
1) patient is given hormone therapy (LH and FSH) to allow eggs to mature and stimulate release of multiple eggs
2) eggs are harvested from patient via surgery
3) sperm sample collected
4) eggs are fertilised by sperm cells (by injection) to form zygotes
5) zygotes divide to form embryos in an incubator at a warm temperature
6) embryos implanted into patient’s uterus
describe how mature eggs are used in IVF so a woman may become pregnant
1) sperm sample is collected and injected into the egg to fertilise it, forming a zygote
2) zygote divides by mitosis in an incubator to form embryos
3) embryos are implanted back into the patient’s uterus
what can premature birth cause
it can cause the baby to be underweight
advantages of IVF
- allows people to have babies of their own
- has a safe track record
- unused eggs can be donated to couples or used for research
