Zusammenfassung der Ressource
Hormones
- Chemical messengers sent in the blood
- Carried in blood plasma to
other parts of the body
- Only affect target cells in
particular places
- Have long lasting effects
- Control things in organs and
cells that need constant
adjustment
- Produced in and secreted by
various glands
- The pituitary gland
- Produces important
hormones including FSH
and LH
- Ovaries
- Produce oestrogen
- Involved in menstrual cycle
- Difference
between nerves
and hormones
- Nerves
- 1) Very FAST action
2) Act for a SHORT
TIME 3) Act on a
PRECISE AREA
- Hormones
- 1) SLOWER action
2) Act for a LONG
TIME 3) Act in a
GENERAL way
- Menstrual cycle
- Four stages
- Day 1 is when the bleeding starts.
The uterus lining breaks down for
about four days
- The lining of the uterus builds up
again from day 4 to 14 into a thick
spongy layer full of blood vessels,
ready to receive a fertilised egg
- An egg is released from
the ovary at day 14
- The wall is then maintained for about 14
days, until day 28. If no fertilised egg has
landed on the uterus wall by day 28 the
spongy lining starts to break down again
and the whole cycle starts again
- Three main hormones
- FSH (Folicle-Stimulating Hormone)
- Causes an egg to mature
in one of the ovaries
- Stimulates the ovaries
to produce oestrogen
- LH (Luteinsing Hormone)
- Produced by the pituitary gland
- Stimulates the release of an
egg at around the middle of the
menstrual cycle
- Oestrogen
- Produced in the ovaries
- Causes pituitary to produce LH
- Inhibits further release of FSH
- Reducing fertility
- Oestrogen
- Taken everyday
egg development
and production
stop
- Progesterone
- Stimulates the
production of thick
cervical mucus which
prevents sperm
getting through
- The pill
- First made in 1950s and
contained high levels of
oestrogen and
progestorone
- Link between blood
clots so lower doses of
oestrogen now
- IVF
- Involves collecting
eggs from ovaries
and fertilises them
in a lab using
sperm. These are
grown into embryos
- Once embryos are
grown the best are
transferred to the
womb to improve
chance of
pregnancy
- FSH nad LH are
given before egg
collection to
stimulate egg
production
- Pros
- Give infertile
couples a child
- Cons
- Strong reaction to
hormones eg.
abdominal pain,
vomiting, dehydration
- Increased risk of cancer
- Multiple births
- Expensive
and doesn't
always work