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 The Endocrine system has 2 major organs responsible for the changes humans go through from child to adult:  Ovaries  Testes

Sexual Reproduction  Life begins as a single cell.  That single cell is produced by the joining of two other cells:  Egg – Female sex cell  Sperm – Male sex cell

Fertilization  Fertilization is the joining of the sperm and egg.  It is an important part of sexual reproduction.  Sexual reproduction involves the production of eggs by the female and sperm by the male.  The egg and sperm join together during fertilization.

Fertilization  A fertilized egg (egg + sperm) is known as a Zygote.  They zygote is a SINGLE cell (egg + sperm).  Inside the zygote are chromosomes. These chromosomes hold ALL your DNA.  It has all the information you need to grow into a human.

Male Reproductive System  The male reproductive system is specialized to produce sperm and the hormone testosterone.  These structures of the male reproductive system include the:  Testes  Scrotum  Penis

The Testes  Oval shaped. Males have 2 (singular testis)  The testes or made of hundreds of tiny coiled tubes.  Sperm is produced in these tiny coiled tubes.

Testes  Produce Testosterone – a hormone that controls the development of physical characteristics in mature men.  Facial Hair  Deepening Voice  Broadening of Shoulders  Ability to produce sperm

Testes  Are located in the Scrotum.  The scrotum is located in an external pouch of skin allowing for a slightly lower body temperature.  Sperm need a slightly lower temperature to remain healthy.

Sperm Production  Sperm production begins in the early teenage years for males.  The head of the sperm contains half the chromosomes needed for a human’s DNA.  It also has a tail to allow for mobility (movement like swimming)

The Path of Sperm Cells  Sperm cells form in the testes.  Then they pass through other structures/tubes and mix with fluids from nearby glands.  This mixture is called semen.  In each drop of semen, there are 5 – 10 million sperm cells!  This fluid allows the environment for sperm to swim.

 Semen leaves the body through and organ called the penis.  The tube the semen exits through is called the urethra.  Urine also exits the body through these tubes.