Lesson 3: Human Reproduction
Lesson 3 Human reproduction
Reproduction and the reproductive System
Human reproduction is sexual, we need male and female cells (gametes), Male cells are spermatozoa and female cells are ovules. Everybody are born with a reproductive system but its inactive. All the changes (in our bodies and personalities) that we suffer take place during puberty.
The male reproductive system
It consists of:
- Testes : Two oval shaped organs (covered by scrotum) that produce spermatozoa.
- Penis: It´s a cylindrical organ covered by skin. Inside it we can find the urethra.
- Prostate and the seminal vesicles: produce fluids that mix with the spermatozoa to form semen (that is released through the urethra).
The female reproductive system
It consists of:
- Ovaries: Two oval shaped organs produce ova . A single ova is called ovum.
- Fallopian tubes: connect the ovaries and the uterus.
- Uterus: It´s a hollow organ. The foetus grow inside it.
- Vagina: Connects the uterus to the exterior of our body.
- Vulva: It´s the external part of the female reproductive system. It´s protected by the labia.
Puberty and sexual maturation
a) In boys, testes produce spermatozoa, the voice gets deeper, hair grows in some places of the body and their body develops.
b) In girls, they have the ability to produce ovas and are released one by one during the menstrual cycle. The breast grow larger, their hips become rounder, hair grows in some places of the body and their body develops.
The menstrual cycle
It´s a process that last twenty eight days. It consist of three parts:
a) Ovulation: When the ovaries release an ovum that travels through the fallopian tubes and reaches the uterus.
b) Preparation of the uterus: The walls of the uterus develop a lining of blood vessels.
c) Menstruation: the ovum, the lining of blood ans a little amount of blood are released from the body.
The processes involved in reproduction
The processes involved in reproduction
- Fertilisation: When a spermatozoa and an ovum join together to create a zygote (normally in the fallopian tubes).
- Development of the embryo: It lasts nine months. In the first trimesterthe amniotic sac, amniotic fluid, placenta and umbilical cord are formed. In the second trimester the zygote turns into foetus and grow. In the third trimester the foetus grows and mature.
- Birth: The cervix dilate, the uterus contracts sand the amniotic sac breaks and the baby and the placenta leaves the mother´s body.
