2.Male Reproductive System 1

Boys have different sex organs than girls 2 In boys, the sex organs are 2 testes

3 Vocabulary: testes Male sex organs that produce hormones and sperm

The testes are on the outside of the male’s body 4 They are in a sac of skin called the scrotum

5 Vocabulary: scrotum A sac of skin that holds the testes in males

Sex organs work as glands and make hormones 6 During puberty, they make a boy’s body change to look more like a man’s body

They are also important in reproduction 7 That is why sex organs are part of the reproductive system

8 Vocabulary: Reproductive system The body system in which sperm cells or egg cells are made

Testes make cells called sperm 9 Vocabulary: sperm The male reproductive cells made in the testes

Sperm are so small you need a microscope to see them 10 Males begin making sperm when the reach puberty and hundreds of millions are made in a lifetime

Millions of sperm leave the testes and pass along a long, thin tube 11 The sperm will mix with fluid to make semen

12 Vocabulary: semen A mixture of a fluid and sperm cells

The semen passes into another tube under the bladder 13 This tube, the urethra, is in the penis and leads semen out of the body

14 Vocabulary: urethra A tube that leads semen and urine out of the male’s body

A sperm cell must come together with an egg cell from a female 15 for a baby to form

First, sperm has a long, threadlike tail that moves back and forth 16 Which helps push the sperm along to swim to the egg cell

If a sperm meets an egg, they can join 17 Only one sperm cell can be used for fertilization of an egg cell

18 Vocabulary: fertilization When a sperm cell joins with an egg cell

The fertilized egg, called zygotes, begins to grow and divide 19 It forms 2 cells

Then the 2 cells divide and form 4 cells and so on to form an embryo 20 In about 9 months a new human life begins that is called a baby