REPRODUCTIVE SYSTEM

(THE FERTILIZED EGG)

Science V

Review

Define fertilization.

Where does fertilization occurs?

How many sperm cells does an egg

cell normally use in order to become

fertilized?

Checking of Assignment

What are germ cells?

Checking of Assignment

What are germ cells?Germ cells are specialized cells whichare involved in reproduction. The mostwell known examples of this type ofcell are gametes, the sperm and eggswhich come together to create azygote which can develop into a fetus.

Motivation

Study

the

picture

Motivation

What do you observe in the

illustration?

Were you like this when you were

inside the womb of your mother?

Presentation

Watch the video clip:

From embryo to fetus

Identify the stages of development of

the human embryo

Compare each stage of development

Presentation

Concept Formation

What happens to the zygote after

fertilization?

Concept Formation

What happens to the zygote after

fertilization?

The zygote undergoes a series of

cell division as it moves along the

fallopian tube.

Concept Formation

Where does the fertilized egg stay?

Concept Formation

Where does the fertilized egg stay?

The zygote is implanted in the

uterus.

Concept Formation

What happens to it in the uterus?

Concept Formation

What happens to it in the uterus?

It has become a many celled human

embryo.

Concept Formation

During the first three months, the

head and the brain of the embryo

developed rapidly and the next three

months, the growth of the body

catches up with the head.

Concept Formation

Around the ninth week, most of the

internal organs are formed, and so

are its face, eyes, ears, nose, mouth

and the beginnings of sex organs. At

this point the embryo is called a

fetus.

Concept Formation

The fetus continues to grow until the

38th week protected by the amniotic

sac.

Concept Formation

How long does the fetus stay in the

uterus?

Concept Formation

How long does the fetus stay in the

uterus?

The fetus stay in the uterus where it

undergoes development for nine

months. This period of development

is called pregnancy.

Concept Formation

How is the fetus nourished while in

the uterus?

Concept Formation

How is the fetus nourished while in

the uterus?

The embryo is connected to the

placenta by the umbilical cord where

nutrients and oxygen pass from the

mother to the embryo.

Application

What should the mother do during

pregnancy? Why?

Application

What should the mother do during

pregnancy? Why?

Evaluation

Differentiate the following:

Zygote

Fetus

Embryo

Evaluation

Zygote

It is the earliest and the first stage of

the new cell which is formed when the

sperm cell unites with the egg cell

during the process of sexual

reproduction.

Evaluation

Fetus

It is the stage of development which

comes after embryo and during it the

body of the baby is almost made and

the internal development takes place.

Evaluation

Embryo

It is the stage of development in which

the cell is divided into different parts.

Assignment

Interview a pregnant woman. Ask

how she feels.