[IB Biology SL Notes: The Reproductive System]

Copulation: Sexual intercourse
Fertilization: Fusion of gametes (egg & sperm). Occurs in oviduct.
Development of the Embryo prior to Implantation:
30 hrs after fert., cell cleavage (division) begins.
Within one week, many cleavages have occurred, forming a blastula (Hollow ball of cells. Inner cluster becomes embryo, outer ring of cells becomes chorionic membrane.)
Hormonal Control of Birth:
Mid Pregnancy:
Estrogen & progesterone levels are high to maintain uterine development & placenta. They also cause development of the mammary glands. High progesterone prevents labor.
At Birth:
Levels of progesterone drop. This allows oxytocin levels to be released. Oxytocin causes uterine contractions that trigger further release of oxytocin (+ feedback).
Milk production- As estrogen & progesterone levels drop at birth, the hormone prolactin is released, causing milk production.


Family Planning:
Mechanical
Condoms
Diaphragm
IUD
Chemical
Oral Contraceptive
Spermacidal gels
Norplant- chemical implant under skin
Behavioral
Rhythmn Method

Ethical Issues of Family Planning/ Contraception
Pros: Cons:


Slichter