1. Reproduction
IS2

2. Sexual Reproduction
• Egg = female sex cell
• Sperm = male sex cell
• Sperm joins the egg = fertilization
• Fertilized egg = zygote
• Zygote divides many times to form the embryo and then the fetus
• Cells contain nucleus where DNA is
• DNA makes up chromosomes = contain all information the cell
needs to work / determine your characteristics
• Humans should have 46 chromosomes
• Some people have more or less than this.
Example: Down Syndrome = 47 chromosomes

3. Male Reproductive System
• Produces sperm
• Produces testosterone = controls the
development of secondary sexual
characteristics and the production of
sperm
• Testes = many tubes where sperm cells
are produced
• Located in scrotum = lower
temperature allow sperm to develop
• Sperm production starts in teenage
years
• Sperm travel with semen (fluid
containing nutrients)
• Path: testes → vas deferens → urethra
(penis)
• Remember: urethra = common
pathway for urine AND semen

4. Female Reproductive System
• Produces eggs
• Nourishes a baby until birth
• Ovaries = produce eggs (only 1
matures every month)
• Also produce estrogen = controls the
development of secondary sexual
characteristics and helps prepare the
uterus for the baby
• Path: ovary → fallopian tube →
uterus
• Uterus = muscular organ where
embryo develops into a baby
• If the egg is not fertilized = it gets
destroyed and leaves the body (along
with the lining of the uterus) through
the cervix and then the vagina

5. Menstrual Cycle
• Every girl is born with about 400,000
undeveloped eggs in the ovaries
• Only about 500 will become mature
and leave (normally one per month)
• Monthly cycle = egg develops + uterus
prepares for the embryo
• Normally takes about 28 days (could
be more or less)
• Ovulation = when the egg is released
from ovary
• Menstruation = lining of uterus +
undeveloped egg leave the body
through vagina
• Hormones control this process
Human embryo at 5-6 weeks