1. David M. Phillips
Reproductive System

2. 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

3. 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 million fit in a teaspoon
Sperm usually live for about 24 hours inside the female reproductive tract

5. 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

6. 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

7. 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

9. 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

11. 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