4ª The reproductive system

by Teacher Alvaro

The reproductive system

Human reproduction needs a male and a female. A zygote is created when a male reproductive cell (a spermatozoon), fuses (se une/fusiona) with a female reproductive cell (an ovum).

Human reproduction

Female reproductive organs

Most of the female reproductive organs are inside the body:- Ovaries- Uterus- Vagina- Vulva

Male reproductive organs

Most of the male reproductive organs are outside the body:- The testicles- The penis- The scrotum

Fecundation

- Human reproduction takes place inside the female body. -The penis enters the vagina and releases (expulsa/libera) spermatozoa.- The spermatozoa swim into the uterus. If there is a fertile ovum in the uterus, a spermatozoon enters the ovum.- The two cells fuse together to become a zygote. This process is called fecundation

Pregnancy 2nd trimester

- For about 40 weeks, the zygote develops and grows into a baby ready for birth. - In the first trimester, the zygote implants in the wall of the the uterus. It is now called an embryo. -The placenta develops in the uterus. Nutrients and oxygen travel from the placenta to the embryo along ( a lo largo de) the umbilical cord.

Pregnancy 2nd trimester

- At the start of the second trimester, the embryo is between five and six centimetres long.- It is now referred to as a foetus. The internal organs develop.

Pregnancy 3rd trimester

- During the third trimester, the foetus grows and gains weight until it is ready for birth.

The reproductive system

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