Homeostasis Flashcards
(16 cards)
The menustral cycle
The menstrual cycle is the process the body undergoes each month to prepare for a
potential pregnancy.
It begins with the lining of the uterus breaking down, and the woman has her period.
The layer then builds up again, until ovulation (day 14) occurs- an egg is released from
the ovary and moves to the uterus via the fallopian tube.
If a fertilised egg has not been embedded in the lining after 28 days, it begins to break
down and the cycle continues.
Follicle stimulating hormone (FSH) ?
causes the maturation of an egg in the
ovary, within a structure called a follicle
● Produced in the pituitary gland
● Stimulates the ovaries to produce oestrogen
Oestrogen ?
causes the lining of the uterus to grow again
● Produced in the ovaries
● Secreted as a result of FSH
● Stimulates the production of LH and inhibits the secretion of more
FSH
Luteinising hormone (LH)
Produced in the pituitary gland
● Produced as a result of the hormone oestrogen
● Its release results in ovulation
Progesterone
Produced in the ovaries and secreted from the egg follicle.
● Maintains the lining of the uterus, and supports a pregnancy if the egg is
fertilised
● Inhibits the release of both FSH and LH
The contraceptive pill
must be taken regularly or the bodies own hormones will be
released, leading to an egg maturing.
● The mixed pill contains oestrogen and progesterone
○ This means the oestrogen levels are constantly high, inhibiting FSH so no
eggs mature.
○ The lining also stops developing and the mucus in the cervix becomes thick
so sperm cannot move through
○ Some possible side effects include changes in mood, mood swings,
depression, breast pain or tenderness, breast enlargement, increased blood
pressure.
● The progesterone only pill
○ This has less side effects in comparison to the mixed pill.
The contraceptive patch
contains oestrogen and progesterone.
● It is small and is stuck on the skin
● Lasts for one week
The contraceptive implant
releases a continuous amount of progesterone.
● This prevents the ovaries from releasing the egg, thickens the mucus in cervix so
sperm cannot swim and stops fertilised eggs from embedding in the uterus
● Lasts for three years
The contraceptive injection i
s made up of progesterone.
● Same effect as the implant
● Lasts for 2 to 3 months
The plastic intrauterine device (IUD)
eleases progesterone.
● Same effect as the implant
● T shaped, inserted into the uterus
Chemical methods involve s…
spermicides. These kill or disable sperm, but are only
70% to 80% effective.
Barrier methods include
condoms and diaphragms:
● Condoms are either worn over the penis or are inside the vagina. They also
prevent the individual from contracting sexually transmitted diseases. A
problem is that it can tear and therefore let sperm through.
● A diaphragm is a plastic cup which is positioned over the cervix. It is used
with spermicide
The copper intrauterine device
works by killing sperm in the uterus and stopping any
fertilised embryos from implanting in the uterus lining.
Fertility drugs are used to increase the chance of pregnancy.
● The main hormones used are FSH and LH because they stimulate the
maturation and release of the egg.
● The woman can then become pregnant normally.
n Vitro Fertilisation (IVF) is another treatment.
● The mother is given FSH and LH to encourage the maturation eggs
● These are extracted from the mother and fertilised in the lab using sperm
● The fertilised eggs develop into embryos and then one or two are inserted in
the uterus
