1. HUMAN FERTILIZATION and IMPLANTATION

2. SPERM CELL(MALE GAMETE)
The mature sperm cell (spermatozoon, plural spermatozoa)
Human sperm cells are haploid, which means that they contain 23 chromosomes.
Function of spermatozoa is to fertilize the egg cell .
Acrosome-Contains a proteolytic enzymes(breaks down proteins) that help to destroy the outer layer of the egg cell, thereby allowing the sperm to enter into it easily.
The tail, also known as flagellum, is a long structure which main function is to allow sperm motility by means of a slithering, snake-like movement.

3. Haploid, which means that they contain 23 chromosomes

4. Fertilization It is the fusion of male & female gametes.
The egg changes so that no other sperm can get in

5. Implantation: Moving to the Uterus
Within 24 hours of being fertilized, it starts dividing fast into many cells by a process called MITOSIS.
The zygote is now called an EMBRYO (COMPOSED of TWO CELLS).
The EMBRYO moves through the fallopian tube to the uterus, it is moved by muscular contractions and the beating of cilia from the epithelial cells lining the oviduct..
Its next job is to attach to the lining of uterus . This is called implantation

6. Pregnancy and Development
The ball of cells develops two parts
Embryo
Placenta
Both are joined by an umbilical cord.
The embryo invades the uterus lining (which is rich with blood vessels) to nourish itself through the maternal blood supply. To obtain nutrients and oxygen, get rid of waste and carbon dioxide by diffusion) .

7. DEVELOPMENT of THE EMBRYO