7B
Sexual reproduction
Female reproductive system
To look at the pathway in which an egg cell is released let’s look at the female reproductive
system.
The female reproductive organs are inside the body and are protected by the bones of the pelvis.
In particular the pelvis protects the uterus – also called the womb – because this is where a baby
will develop if the woman becomes pregnant.
The vagina is the tube that leads from the outside of the woman’s body to the lower end of the
uterus.
The cervix is located at the entrance to the uterus.
The diagram also shows the bladder (underneath the uterus).
The function of the bladder is to store urine. It is not part of the reproductive system but is very
close by.
The two tubes leading down to the bladder come from the kidneys.
Here you can see the remaining female reproductive organs – two ovaries, and the tubes that lead
from the ovaries to the uterus.
Here’s another view of the vagina and uterus, this time without the bladder.
Either side of the uterus are the fallopian tubes (or oviducts) which lead to the ovaries.
Girls who have reached puberty release egg cells from the ovaries about once every 28 days. Egg
cells are the female gametes.
The egg travels from the ovary to the uterus via the fallopian tubes.
If the egg is fertilised it will implant in the uterus where it will develop into a baby.
Male reproductive system
To look at the pathway in which sperm are released, let’s look at the male reproductive organs.
The external male reproductive organs are the penis and the testes.
The testes have no muscle or bone to protect them, just the scrotum which is a bag of skin
dangling outside the body that holds the testes.
There are two testes – the grey sacs. One of them is called a testis.
Boys who have reached puberty make sperm cells in the testes. Sperm cells are the male
gametes.
The diagram also shows the bladder (the large pink cone at the top). The function of the bladder is
to store urine. It is not part of the reproductive system but is very close by.
The two tubes leading down to the bladder come from the kidneys.
Each sperm cell has the potential to fertilise an egg cell, or female gamete. This is how humans
reproduce.
To reach the egg cell, the sperm cells must leave the testes.
The sperm duct connects the testes to the urethra.
While passing through the sperm duct, the gland adds liquid to the sperm cells.
The mixture of sperm cells and liquid is called semen.
The urethra has two functions – to carry both urine and semen … but never at the same time.
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