endocrine Flashcards
what is contraception
Contraception = preventing pregnancy by
what is oral contraception
Oral contraception - these pills contain female hormones
the combined oral contraceptive pill contains low doses of oestrogen and progesterone
How does the combined oral contraceptive pill prevent pregnancy?
the contraceptive pill prevents pregnancy because ;
it contains oestrogen which inhibits fsh
it contains progesterone which inhibits the use of fsh and lh
fsh causes eggs to mature
lh triggers the release of the egg
if both of these homones are inhibited it wont allow an egg to develop and would prevent a pregnancy
Another contraceptive pill stops progesterone from being produced. How does this pill prevent pregnancy?
without a uterus lining there will be no where for the egg to be implanted
how can pills that make mucus prevent pregnancy
There are pills that make mucus in the cervix, in order to prevent sperm getting through
how does a contraceptive implant work and what does it release
tiny tube inserted under the skin by a doctor –> slowly releases progesterone
what are contraceptive injections? how long do they last
progesterone only injections - only last 12 weeks
what is a contraceptive patch?
Patch is stuck to the skin and replaced every 7 days - hormones are directly released into the bloodstream
what do contraceptive patches release
contains oestrogen and progesterone
what are spermicides and are they effective
chemicals that kill or disable sperm - not very effective
how do condoms prevent pregnancy?
prevents the egg and sperm from meeting
what are 2 advantages of condoms
No side effects, offers protection against some STDs
what is a disadvantage of condoms
they can get damaged and sperm can get through
what is a cap
thin rubber diaphragm that is placed over the cervix before intercourse to prevent entry of sperm
what is advantage of a cap
no side effects
what are Intrauterine devices (IUDs)
small structures inserted into the uterus by a doctor
how long do IUDs last
these last for 3-5 years - and can be removed any time if you want to become pregnant
what is the rhythm method?
abstaining from intercourse around ovulation
what is a vasectomy?
sperm ducts are cut and tied to prevent the sperm from getting into the semen
what is Tubal sterilisation
Women can get their oviducts (fallopian tubes) cut and tied to prevent an egg reaching the uterus
name 3 things that are linked to infertility
a lack of female hormones
damaged oviducts
lack of sperm in the semen
what are 3 common causes of infertilty
obesity
eating disorders (anorexia nervosa, bulimia)
age
what does IVF stand for
IVF = In Vitro Fertilisation
what is in vitro
In Vitro = within cells - so this means you are fertilising on a cellular level - in a lab, in a petri dish
under what cirucumstances can IVF be used
- the oviducts have been damaged/blocked by infection
- a donor egg has to be used
- there is no obvious cause for long term infertility
- if a man produces very little sperm or the sperm has not matured
what hormones are given in fertility treatment
A combination of FSH and LH can be used in fertility treatments to cause eggs to mature in the ovary and to trigger ovulation
what is the function fsh
matures trhe egg
what is the function LH
triggers the release of an egg
what is the function of prostrogen?
maintans uterus lining
what is fertilisation
when the nuclei of the egg and the sperm fuse
what is a fertilised egg called
zygote
what is the process of ivf
Doctors give the mother synthetic FSH and LH –> to stimulate maturation of egg and ovulation
Collect the egg from the ovary and collect the father’s sperm and fertilise them in the lab -
fertilisation =when the nuclei of the egg and the sperm fuse
Fertilised eggs (zygotes) kept in special solution in warm conditions to develop into embryos
When they are minute balls of cells, one or two are inserted back into the mother’s uterus
what are the advantages of ivf
IVF increases the chance of multiple pregnancy
the mature eggs produced by a woman using fertility drugs may be collected and stored –> ethical issues
what are the disadvantages of ivf
Expensive for society and people –> many will want to pay for repeated treatments
Not always successful - especially with age
Younger gametes (sex cells - egg cell and sperm cell) can be used BUT they won’t biologically be the parent’s child
Has health risks for mother - is emotionally and physically stressful
Costs hospital a lot to incubate premature births –> if they survive they are most likely to be severely disabled.
what is tropism
Tropism = the movement of the plant in response to a stimulus
what is stimulus
Stimulus = a change in the environmen
what is Phototropism
Phototropism = plant’s response to light
what is Gravitropism/Geotropism
Gravitropism/Geotropism = plant’s response to the force of gravity
what happens in photoropism
Auxin moves from the lit side of the shoot to the unlit side
Cells on that side become elongated by the auxin, causing the shoot to bend towards the light
Once light falls evenly on the shoot, the auxin levels will be equal on both sides, so grows straight again
what is gibberellins
Gibberellins = plant hormones
what are gibberellins important for
important in initiating seed germination
and
at the start, giberellins trigger the breakdown of food stores at the start, and stimulate the growth of plant stems
what is ethene used for
- important in controlling cell division
- important in fruit ripening
how does dipping plants in to root powder effect the plant
By dipping or cutting into rooting powder, that contains auxin (IAA), chances of success are higher
what are auxins useful for
Auxins make effective weed-killers
describe how auxins(weed killers) kill plants
when sprayed, it’s absorbed, sending the plant into rapid uncontrolled growth, which kills it
what are selective herbicides?
Selective herbicides = herbicides that affect specific plants
what are 3 uses of gibberellins
Brewing industry = speeds up germination of barley seeds which are used to make malt
Promotes flowering throughout the year, especially in pot plants
Increase the size of fruit
