Have you ever wondered how you came to be? How you became what you are?
At one point in your life, you were just a single cell and then developed into the billion cell organism you are today.

Fertilisation and Implantation

You’ve noticed by now that both the man and the women produce 1 cell.

A sperm cell and an egg cell.

These types of cells are called Gametes. They are special cells, designed only for reproduction.

A male Gamete and a female Gamete, contain ½ the DNA that every other cell in the body has.

50% of what makes you, you is in these gametes.  

When these 2 gametes meet, they form a whole cell with 100% of the DNA needed to make a new person.

The joining of these two is called fertilisation.

The video to the left shows a sea urchin sperm fertilising sea urchin eggs. At the 50 second mark one sperm makes it in.

The female reproductive system is a big place, so how do they get around?

If we look at a sperm cell, we notice the have a long tail (Flagella) which helps them ‘swim’ towards the egg.

However the egg doesn't have a tail or legs. Instead tiny little hairs (Cilia) lining the oviducts push the egg through the oviduct to the uterus.

When people have sex semen is released from the male into the females vagina.

When a male become sexually aroused, his penis fills with blood and becomes erect.

When a women becomes sexually aroused her vagina become moist, allowing the penis to enter her vagina.

Once inside the vagina the man ejaculates and released semen.

Once the sperm has entered the vagina, they swim to the uterus. They pass the cervix, swim through the uterus and make their way to the oviduct.

The egg is fertilised while in the oviduct and brought to the uterus where the baby develops.

The fertilised egg divides several times forming a ball of cells called an embryo. The embryo attaches to the lining of the uterus and develops. This is called implantation.

Quick Questions

1. Define the term Gamete?

2. What makes a Gamete so different from every other cell in the human body?

3. When is an egg fertilised?

Quick Questions

1. How do sperms move? And how do eggs move through the oviduct?

2. What happens when a sperm meets an egg?

Questions

Short Answer Questions

1. Define the following terms:

a. Fertilisation

b. Ejaculation

c. Cilia

d. Implantation

2. Copy and complete the sentence

An _____ is released from the ovaries of a woman and is moved down the ________ by tiny hairs called ________ .

A man releases millions of _________ into the woman’s vagina. The sperm cells swim to the egg cell using a tail like structure called a ________. Only around 100 sperm make it to the egg, while only_____ sperm actually joins with the egg. This process is called _______ .

3. What is the purpose of sperm?

4. Where are the egg cells made?

Extension

5. Create a comic strip of the fertilisation and implantation. Starting with the sperm swimming towards the egg and ending with the ball of cells implanting in the uterus.

(If you’re having trouble remembering the stages move the box bellow)

1. Sperm swim towards the egg

2. Sperm fertilises the egg

3. Egg cell divides

4. Egg continues to divide forming a ball of cells

5. Call of cells move down the oviduct

6. Ball of cells reach the uterus

7. Ball of cells implants