David M. Phillips
*
* Male Anatomy
* Sperm Production takes place in the testes which
are located in the scrotum
* Located outside the body because sperm can
develop only in an environment with a temperature
2-3 degrees Celsius lower than normal body
temperature
* Muscles in the scrotum contract in response to cold
temperatures and relax in warm weather
* Formation of Sperm
* Within each testis is a fine network of highly coiled tubes. Sperm
are produced by meiosis of the cells that line these tubes
* Recall that meiosis produces 4 haploid cells
* Each of these haploid cells develop into sperm over a period of
about 74 days
* A sexually mature male can produce about 300 million mature
sperm per day, about 400-500 million fit in a teaspoon
* Sperm usually live for about 24 hours inside the female
reproductive tract
* Sperm are highly adapted for
reaching and entering the female
egg
* The head portion contains the
nucleus and is covered by a cap
with enzymes that help penetrate
an egg
* Mitochondria are found in the
midpiece to provide energy
* The tail is a typical flagellum
California Dept. of Education
* The path of sperm
* Before the sperm mature they leave the testes
through a series of coiled ducts that empty into a
single tube called the epididymis where they
mature
* From the epididymis the sperm enter the vas
deferens where they are stored for as long as 2-3
months
* The sperm is transported out of the body via the
urethra (same structure transports urine out of
the body)
* A muscle prevents urine and sperm from mixing
* When the sperm travels from the testes, they mix
with fluids secreted from several different glands
* Seminal vesicles secrete a fluid rich in sugar
fructose (energy)
* The prostate gland secretes a thin, alkaline fluid
that helps the sperm move and survive
* Bulbourethral glands secrete an alkaline fluid to
neutralize the acidic environment of the male
urethra and female vagina
* The sperm and all these fluids together is called
semen
* Female Anatomy
* The main function of the female reproductive
system are:
* To produce eggs
* Receive sperm
* Provide an environment for a fertilized egg to develop
* Egg production takes place in the two ovaries (in
humans each is about the size of an almond)
* The eggs are transported from the ovary to the
uterus via the oviduct
* The uterus is where a fetus develops during
pregnancy (about the size and shape of a pear) and
is composed of three layers:
* An outer layer of connective tissue
* A thick, muscular middle layer
* A thin, inner lining called the endometrium
* The lower end of the uterus tapers to a narrow opening
into the vagina
* Production of eggs
* With males, sperm production does not occur until
puberty and continues the rest of their lives
* Egg production is different: even before a female is
born, her body begins developing eggs
* Before birth, the cells in the ovaries divide until the
first stage of meiosis and then go into a resting stage
* At birth, a female’s ovaries contain around 2 million of
these potential eggs called primary oocytes
* Over time, many oocytes break down or degenerate
* At puberty, a female’s ovaries contain around 40,000
primary oocytes
* About once a month the process of meiosis starts up
again and continues through meiosis. During which,
one of the egg cells ruptures from the ovary and passes
into the oviduct (ovulation)
* A total of around 400 eggs are ovulated during the
reproductive life of a female