Science f r s

• 1. Fertilization results in the formation of a diploid zygote.
• As the zygote moves through the uterus mitotic division occur in the zygote, forming blastomere.
• 1. Embryo with 16 celled stage is known as a morula.
• 1. Morula undergoes further cleavage and develops into a blastocyst. The cells of the blastocysts get arranged into an outer layer called trophoblast and inner cells called inner mass.
• 1. Morula undergoes further cleavage and develops into a blastocyst. The cells of the blastocysts get arranged into an outer layer called trophoblast and inner cells called inner mass.
• 1. Trophoblast layer of blastocyst gets attached to the endometrium while inner cell mass differentiates to form an embryo.
• 1. After attachment, the uterine cell divide rapidly and causes the blastocyst to become embedded in the endometrium of the uterus. This leads to pregnancy
• cell division takes place

  as the

  zygote travels back down the oviduct towards the uterus,
• The zygote will journey

  Of six to

  seven days after fertilization.
• eventually

  the zygote becomes a small ball of cells

  BLASTOCYST that attaches

  itself to the uterine wall in the process called implantation.
• The zygote is now called an embryo
• • nine months from the time the embryo becomes implanted

  on the walls of the uterus

  called pregnancy, until the baby is born
• • duringthe first two months of

  pregnancy, the developing

  child is called

  an embryo
• • part of the uterine wall produces the villi which constitutes the placenta, along.

  with other blood vessels and capillaries.
• • umbilical cords form and connects the placenta to the embryo, nutrients

  and oxygen in the mothers

  mother'sblood are transported to the embryo through veins

  in

  the umbilical

  Cord.
• • carbon dioxide and other ways are carried away form an embryo throughan artery inthe umbilical cord to themother's bloodstream for disposal.
• • during the third week of pregnancy,athinmembrane called the amniotic sac begins to form around the embryo.
• The amniotic sac becomes

  filled with a clear liquid called the

  amniotic fluid which helps cushlon and protect the embryo.
• A fertilized egg or zygote, takes about five days to reach the uterus from

  the

  uterine tube.
• A fertilized egg or zygote, takes about five days to reach the uterus from

  the

  uterine tube.

  As it moves.

  the

  zygote divides

  and

  develops into a blastocyst ( about 6 days after fertilization, the cell cluster from a hollow cavity

  is known as blastocyst with

  an inner mass of cells and a protective

  " outer ring
• The blastocyst attaches to the wall of the

  uterus and gradually implants itself

  into the

  uterine
• during the third month of pregnancy, the developing begins

  to look more human-

  eyes,

  fingers

  toes , arms, and legs will

  have

  developed - and is now called fetus.
• By the

  Ninth month, the fetus has usually rotated to a head-down

  position inside the uterus
• • The

  birth

  process begins with the onset of labor, the

  muscular contractions of the uterus
• around week 36 (usvally), the process of

  labor begins
• * In

  the first stage ,dilation hormone stimulate

  downward contractions Of the

  uterine walls.
• • the

  contractions push the head of the fetus against

  the

  cervix

  Of the lower

  end of the uterus.
• * In

  the

  2nd

  stage

  contractions push the

  expulsion, powerful head and the rest

  of the body through the dilated cervix,

  and

  OUt to the vagina and the vulva
• .

  Further contractions

  expel the placenta