1) A zygote is formed when a sperm fertilizes a secondary oocyte in the fallopian tube. 2) Immediately after formation, the zygote begins moving towards the uterus and undergoing mitotic cell division called cleavage. 3) Cleavage results in the zygote dividing into smaller blastomeres over 6-7 days as it travels through the fallopian tube and into the uterus, eventually forming a structure called a blastocyst.

1. D R E A M

2. BISHNUPRIYA LENKA
M.SC NURSING 2nd YEAR
KINS, KIIT DU UNIVERSITY

4. INTRODUCTION
• Zygote is the cell resulting from the fertilization of a secondary
oocyte by a sperm.
• The secondary oocyte finishes its second meiotic division
immediately after the entry of the sperm and becomes ovum.

6. • Fertilization occurs in the ampullary part of fallopian tube so zygote is
formed in the ampullary part of fallopian tube.
• Immediately after its formation it starts:
• 1. Moving towards uterus
• 2. Multiplying mitotically

7. • Cleavage is a mitotic type of cell division
where the daughter cells are smaller than
the parent cells.
• The number of cells increases but the
size of the daughter cells and the cell-
mass does not increase.

8. • Zygote immediately after its formation, in the ampullary part, is
guided medially through the uterine tube toward the uterine cavity.
• As the zygote, passes through the uterine tube, it undergoes mitotic
cell divisions known as cleavage.This phase of development begins
with the first mitotic division of the zygote and ends with
formation of blastocyst.
• It extends for 6 to 7 days or a week.

9. • The 1st division of zygote gives rise to two daughter cells. They are
called blastomeres.
• Each blastomere is half the size of parent cell. They develop about 30
hours after fertilization.
• Subsequent divisions follow one another, forming progressively
smaller blastomeres.
• After three or four divisions, the zygote, looks like a mulberry
and is known as morula .

10. • It is a solid mass of 12 to 16 cells (blastomeres).
• This stage is reached about three days after fertilization and the mass of
cells is about to enter the uterus.
• During the formation of blastocele the cells of outer cell mass becomes
flattened.
• So the outer cell mass is now a single layer of flattened cells forming the
wall of blastocyst and it is now given the name trophoblast .

14. A Zygote formed from the union of two gametes both bearing
X sex chromosomes (XX Zygote) normally developes as a
genetic and biological female .

15. BIBLIOGRAPHY:-
• Dutta DC .Text book of obstetrics including perinatal and
contraception central publication 8th edition. pgno. 24-25.
• Jacob annama ,text book of comprehensive text book of
midwify and gynecology nursing jaypee publication3rd
edition pg no- .
• https://www.bing.com/videos/search
• https://www.slideshare.net/farhanali911/zygote

16. ASSIGNMENT