HOMEOSTASIS #2 Flashcards
What is the main female reproductive hormone?
oestrogen
where is oestrogen produced
the ovaries
the menstrual cycle- what happens
every 28 days a mature egg is released from its ovary, if the egg is not fertilised, the lining of the uterus along with the egg is shed around 14 days later.
what is it called when a mature egg is released from the ovary
ovulation
what are the hormones involved in controlling the menstrual cycle and what do they do
FSH- causes the egg in the ovary to mature
LH- stimulates the release of the egg at ovulation
oestrogen and progesterone- stimulates the build up and maintenance of the uterus lining
what happens each month in the ovary
eggs begin to mature and the uterus produces a thickened lining ready for pregnancy
what is the main male reproductive hormone and where is it produced
testosterone and in the testes
what 4 hormones interactions coordinate the events of the menstrual cycle
FSH, LH OESTROGEN AND PROGESTERONE
FSH- detailed
is secreted by the pituitary gland
makes eggs mature in their follicles in the ovaries
stimulates the ovaries to produce hormones including oestrogen
oestrogen- detailed
is made and secreted by the ovaries in response to FSH
stimulates the lining of the uterus to grow again after menstruation in preparation for pregnancy
inhibits the production of more FSH and stimulates the release of LH when oestrogen levels are high
LH-detailed
is secreted by the pituitary gland
stimulates the release of a mature egg from the ovary
levels fall again once ovulation has taken place
progesterone- detailed
is secreted by the empty egg follicle in the ovary after ovulation
is one of the hormones that helps to maintain a pregnancy if the egg is fertilised
inhibits both FSH and LH
maintains the lining of the uterus in the second half of the cycle.
name the two hormones produced by the pituitary gland that are involved in controlling the menstrual cycle
FSH AND LH
which hormone inhibits FSH
oestrogen
what two hormones are present in contraceptive pills
oestrogen and progesterone
what do contraceptive pills do
they inhibit FSH production so no eggs are released
stop the uterus lining developing preventing implantation
make the cervix thick to prevent sperm getting through
why is artificial FSH given to infertile woman
some women do not make enough FSH to stimulate the maturation of the eggs in their ovaries
THE artificial FSH stimulates the eggs in the ovary to mature and also trigger oestrogen production
what does IVF involve
this involves giving a mother FSH stimulate the maturation of several eggs followed by LH to stimiulate the ovaries to the point of ovulation, they are collected, fertilised allowed to start development and replaced in the uterus
disadvantages of ivf
very expensive
not very successful
emotionally and physically stressful
what are plants sensitive too?
light and gravity
what are plant responses called
tropisms
when plants grow towards the light what is this response called
phototropism
when roots grow down towards gravity what is this response called?
gravitropism
what is auxin
it is the hormone that controls phototropism and gravitropism
what does an uneven distribution of auxin cause
it causes unequal growth
what direction will the shoot grow if the light is the same all around the shoot, the distribution of auxin is equal and the cells grow at the same rate
the shoot will grow upwards
what happens when light falls to one side of the shoot
there is more auxin on the unlit side of the shoot
the auxin on the unlit side causes the cells on the unlit side to increase in length more than those on the lit side
so the shoot bends towards the light
what does an uneven distribution of auxin cause
this causes an uneven growth of cells resulting in a bend in the stem
two uses of auxins and who uses them-
can be used as a weed killer
can be used to stimulate root growth (cuttings)
GARDENERS(HORTICULTURE)
give two uses of gibberellins and who uses them
to promote flowering throughout the year
to increase the size of fruit
FARMERS(AGRICULTURE)
use of ethene
encourages fruit to ripen
what happens when plant hormones are used incorrectly
they can cause damage to the environment.
how does a healthy kidney produce urine
it filters the blood
it then reabsorbs all the glucose and dissolved minerals your body need
it also absorbs as much water as your body needs
it then releases urea, excess mineral ions and water in the urine
what processes in the kidney form urine from the blood
filtration and selective reabsorption
what can be done if a person has kidney failure
they can be connected to a kidney dialysis machine
kidney transplant
what is the purpose of kidney dialysis
to remove urea from the blood and restore normal concentrations of substances in the blood
where can kidneys be obtained from
victims of a fatal accident or a living donor
what must the new kidney have to prevent rejection
a vey good tissue match
what might happen when the kidney goes into the patient
the patients antibodies might attack the antigens on the kidney because they recognise them as being foreign
what drugs must the patient take to prevent rejection after the transplant
immunosuppressant drugs
the placenta
The placenta is an organ that develops in your uterus during pregnancy.
ethical issues ivf
Some people worry about the ethical implications of IVF. They are concerned that couples may want ‘designer babies’ with ‘desirable’ qualities, so may only want certain fertilised eggs. For example, they may want a girl if they have lots of boys in the family.
embryos being destroyed
