1. Hormone
B.6.3 Describe the mode of action
of oral contraceptives

2. MENSTRUAL CYCLE
Beginning of the menstrual cycle
o pituitary gland releases follicle-stimulating
hormone (FSH)
o FSH travels to the ovaries --> causes release
of estrogen
 prepares for release of an egg from the
ovary
 prepares for build-up of the uterine wall to
accept the egg once it is fertilized

3. after two weeks the Luteinizing hormone
(LH)
o is released from the pituitary gland
o travels to the ovaries
o releases progesterone then causes the egg
to be transported to the uterus
o build up the uterine wall continues
If the egg is fertilized
o egg embeds in the uterine wall
o hormone levels rises dramatically
If the egg is not fertilized
o hormone levels fall
o menstruation begins

4. PREGNANCY
LH  Progesterone : Prevents ovulation
FSH Estrogen : Prevents irregular
flow during a
menstrual cycle

5. AVOID PREGNANCY
1. Oral contraceptive pill combines a synthetic
progesterone and estrogen.
2. To stop the release of follicle stimulating hormone
(FSH) and luteinizing hormone (LH) by the pituitary.
3. Inhibits ovulation
4. Stops the development of the uterine lining which then
prevents the attachment of the egg to the wall of the
uterus
5. Thickens the mucus around the cervix preventing
sperm from entering the uterus (minipil; hard for sperm
to enter uterus
6. Female reproduction system is fooled by the synthetic
progesterone and estrogen

6. Question
Outline the mode of action of oral contraceptives
Answer:
The "pill" consists of estrogen and progesterone hormones
(synthetic). The excess of these hormones (at a given dosage)
will prevent ovulation, thus avoiding pregnancy. -Negative
feedback control--The increased levels of estrogen inhibit the
levels of LH hormone released by the pituitary gland. The drop
in LH and FSH levels stops the development of the
endometrium lining-without it the egg cannot implant and
therefore no pregnancy will occur.
3 marks

7. B.6.4 Outline the use and abuse of steroids

8. USE
Muscle growth
Minimal side effect so can help people suffer in cancer to increase body weight
Improve performance
Increase body weight (woman > man, because woman has low concentration of
testosterone in body)
Prevent anemia (stimulate red blood cell production)
Treat autoimmune disease (short-term reduction in white blood cell counts by either
interfering in the way they are recycled or directly killing them)
E.G: rheumatoid arthritis

9. ABUSE
MAN WOMAN
Impotence Build up of muscle like a man
Baldness Facial hair
Frequent urination Voice deepens
Lower sperm count Abnormal menstrual cycle
Develop breasts
Risk to prostate cancer
Smaller testes
Develops violent temper
Aggressive behavior
Increase risk of diseases; liver tumors, high blood pressure and heart attacks, increase
LDL, decrease HDL, jaundice, severe acne, mental state, skeletal growth, fluid
retention and kidney tumor,
http://sportsci.org/encyc/anabstereff/anabstereff.html
http://ibhumanbiochemistry.wikispaces.com/C.6.4