Grade by Grade
D. Healthy Living · Healthy Living

Menstruation and Sperm Production: How They Work

D1.4 A1.5 A1.2About 45 minutes
Learning goals
  • I can describe the process of menstruation (having a period).
  • I can describe the process of spermatogenesis (making sperm).
  • I can explain how these processes relate to reproduction and to growing up.

Words to know

menstruation
The monthly shedding of the lining of the uterus, which leaves the body through the vagina. Also called a period.
menstrual cycle
The repeating cycle, about a month long, in which an egg is released and the lining of the uterus builds up and is shed.
ovulation
When an ovary releases an egg, about once a month.
spermatogenesis
The process of making sperm in the testicles. It starts at puberty.
fertilization
When a sperm cell and an egg cell join. It is the first step in making a baby.
wet dream
When semen comes out of the penis during sleep. It's a normal part of puberty. Also called a nocturnal emission.

Two processes, one big purpose

Last lesson you learned the parts of the reproductive system. Today you'll learn about two processes that start at puberty: menstruation and spermatogenesis. Both are signs that the body is growing up, and both are connected to how a new life can begin.

Menstruation: the menstrual cycle

Starting at puberty, a person with a female reproductive system has a menstrual cycle, about once a month. Here's what happens:

  1. The lining builds: hormones tell the lining of the uterus to get thick and soft, with extra blood and tissue. It's getting ready in case a fertilized egg arrives.
  2. Ovulation: about halfway through the cycle, an ovary releases one egg. It travels through the fallopian tube toward the uterus.
  3. If the egg is not fertilized (joined with a sperm), the egg breaks down. The thick lining is not needed.
  4. Menstruation (the period): the lining, mixed with some blood, slowly leaves the body through the cervix and vagina. A period usually lasts about 2 to 7 days. Then the cycle starts again.

Although it can look like a lot, the total amount of fluid in a period is usually only a few tablespoons.

PeriodLining buildsLining stays thickEgg released (about day 14)Day 1Day 28No fertilized egg? Lining is shed: next period.
A typical menstrual cycle shown as about 28 days (not exact). Real cycles are often shorter or longer, and are often irregular for the first few years. That's normal.

Facts about periods

  • Most people get their first period sometime between about 10 and 15. Earlier or later can be normal too.
  • Before the first period, many people notice a clear or whitish discharge in their underwear. That's normal.
  • Periods may be irregular for the first year or two.
  • Some people get cramps (aches in the lower belly). A warm cloth, gentle activity or rest can help. A parent can decide about pain medicine. Very bad pain should be checked by a doctor.
  • Products: pads, tampons, menstrual cups and period underwear. Change them regularly and follow the package directions (tampons should be changed every 4 to 8 hours and never left in longer than 8 hours).
  • You can still go to school, play sports and swim (with a tampon or cup) during a period.
  • Keep a period kit in your backpack: a pad, clean underwear and a small bag.

Spermatogenesis: making sperm

Starting at puberty, the testicles begin to make sperm. This process is called spermatogenesis (sper-ma-toe-JEN-uh-sis).

  1. Hormones, especially testosterone, signal the testicles to start making sperm.
  2. The testicles make millions of sperm cells every day, and usually keep making them throughout adult life.
  3. Each sperm has a head (which carries information from the parent) and a tail that helps it swim.
  4. New sperm move to the epididymis to mature and be stored.
  5. Sperm travel through the vas deferens, mix with fluid from the seminal vesicles and prostate gland to make semen, and can leave the body through the urethra in the penis. This is called ejaculation.
  6. Sperm that aren't used are broken down and absorbed by the body.
head: carries information from the parenttail: whips back and forth to swimNot to scale: a real sperm cell is far too small to see without a microscope.
A sperm cell has a head that carries information from the parent and a tail that helps it swim.

Facts about erections and wet dreams

  • An erection is when the penis gets firm because extra blood flows into it. During puberty, erections can happen often, even without a reason, like during class. That's normal and will pass. Wearing snug underwear, sitting down or holding a book can help until it goes away.
  • A wet dream is when semen comes out during sleep. It's normal, it's not something a person controls, and it's nothing to be embarrassed about. Just wash up and change into clean clothes and sheets.

How these processes relate to reproduction

Reproduction means making a new living thing. In humans, it starts with fertilization: when one sperm cell joins one egg cell. This usually happens in a fallopian tube. The fertilized egg can then attach to the thick lining of the uterus and slowly grow into a baby over about nine months.

So:

  • Menstruation is part of the cycle that prepares the uterus each month.
  • Spermatogenesis makes the sperm.

How they relate to overall development

These processes are a sign that the body is maturing. But having a body that is physically able to reproduce does not mean a person is ready to be a parent. Being ready also takes emotional and social maturity: being an adult, being able to care for a child, and making responsible decisions. That comes much later.

Worked example

Let's trace one menstrual cycle

Put these steps in order: (a) lining leaves through the vagina, (b) lining of the uterus builds up, (c) egg is released by an ovary, (d) egg is not fertilized and breaks down.

  1. The cycle starts with the lining getting ready: (b).
  2. About halfway through, ovulation: (c).
  3. The egg isn't fertilized: (d).
  4. The lining isn't needed, so it is shed as a period: (a). Then it starts again.

b, c, d, a, and then the cycle repeats.

Worked example

Let's trace a sperm's path

Put the parts in order for the path of sperm: urethra, testicle, vas deferens, epididymis.

  1. Sperm are made in the testicle.
  2. They mature and are stored in the epididymis.
  3. They travel through the vas deferens, and fluid is added to make semen.
  4. Semen leaves the body through the urethra in the penis.

Testicle, epididymis, vas deferens, urethra.

Hands-on activity

Make a puberty kit

You need: a small zip bag or pencil case, and a grown-up.

With your grown-up, pack a kit you can keep in your backpack or gym bag. Choose what fits your body and needs. Ideas: a pad or two (for anyone who has or may soon have periods), a spare pair of underwear, deodorant, a small pack of tissues, a wipe, a resealable bag for used items.

Then talk about these questions together:

  1. Who could you ask for help at school if you needed something (for example, the school office, a teacher, or the school nurse)?
  2. What would you say? Practise: "Can I go to the office? I need to get something."

What to look for: your child knows what each item is for and has a plan for asking for help privately.

Your turn

1

What is menstruation?

2

What is ovulation?

3

How long does a period usually last?

4

What is spermatogenesis, and where does it happen?

5

When does sperm production start?

6

What is fertilization?

7

Name two products people can use during a period.

More practice: warm-up

1

True or false: a wet dream is something to be ashamed of.

2

Does an egg come from an ovary or a testicle?

3

About how often does the menstrual cycle repeat?

4

Which part of a sperm helps it swim?

5

Can a person play sports during their period?

More practice: on your own

1

Why does the lining of the uterus get thick each month?

2

Why is the lining shed during a period?

3

Is it normal for periods to be irregular at first? Explain.

4

Explain why an unexpected erection in class is nothing to worry about.

5

What is semen made of, and how does it leave the body?

Challenge

1

Explain how menstruation and spermatogenesis are each connected to reproduction.

2

Your friend says, "If your body can make a baby, you're grown up." Do you agree? Explain.

3

Make a timeline of five steps in the menstrual cycle, starting with day 1 of a period.

Check your understanding

Quiz

1.

During a period, what leaves the body?

2.

Ovulation is when...

3.

Spermatogenesis happens in the...

4.

Fertilization is when...

5.

A wet dream is...

6.

Why is the lining of the uterus shed during a period?

For parents and teachers

Big idea: This lesson covers the Grade 5 expectation to describe the processes of menstruation and spermatogenesis, and explain how these processes relate to reproduction and overall development (D1.4).

About this content: This lesson is part of Ontario's human development and sexual health expectations. In Ontario, parents may request that their child be exempted (opted out) from human development and sexual health instruction at school; ask your school about its process. If your child is exempted, you may skip this lesson at home too, or teach it in your own way.

The lesson explains fertilization as "a sperm cell and an egg cell join" and does not describe sexual intercourse; in Ontario, that is taught in later grades. If your child asks how the sperm reaches the egg, you can answer according to your family's values, or say it will be covered when they're older.

How to help at home:

  • Make the puberty kit together and show your child where period products are kept at home.
  • Normalize: "Periods and wet dreams happen to almost everyone as they grow up."
  • Make sure all children learn about both processes, so they can be understanding and kind to classmates.
  • Talk with your doctor if your child has very painful periods, very heavy bleeding, or worries about their development.

Common difficulties: confusing ovulation with menstruation; thinking a period is an injury; embarrassment about erections or wet dreams.

This lesson builds self-awareness (A1.5) and coping (A1.2) by making these changes less worrying.