Reproduction in humans

Where do babies come from?

To create a new human, a male sperm must fuse (join) with a female egg.

In any normal human cell there are 46 chromosomes; while in sperm and egg cells there are only 23 chromosomes in each.

Upon fusion 46 chromosomes will be present, this cell is now called a zygote.

Sperm and egg (ovum)

Sperm cells are much smaller than egg cells.

Sperms are produced in the testis while eggs are produced in the ovaries.

CytoplasmNucleus , containing 23 chromosomes

Tail, used for swimming

Head

Neck

Tail

Nucleus , containing 23 chromosomes

Jelly coat

1ry and 2ry sexual characteristics

Testosterone hormone in males, produced in testis cause the:

Production of sperms. Growth of the

reproductive organs. Growth of body hair Increased muscular

growth, broadening of shoulders

Deepening of voice Growth of bones

Oestrogen hormone in females, produced in the ovaries cause the:

Production of eggs. Growth of the

reproductive organs Beginning of

menstrual cycle Growth of hair Development of

breasts Deposition of fats on

hips and thighs

ispenis

urethera

Menstrual cycle

A

B

C

E

F

D

Feed

ing

the b

ab

y

Bre

ast m

ilk

It contains easily digestible proteins. Breast milk contains antibodies which help

the baby to fight diseases. The breast milk has body temperature

which is suitable for the baby. Breast milk does not require sterilisation. Breast feeding creates a bond between the

mother and her baby.

Form

ula

milk

Milk is modified to contain digested proteins

Does not contain antibodies Has to be adjusted to body temperature Requires sterilisation Can help a mother that cannot breast feed

due to illness to bond with baby.