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Pregnancy Assignment December 12th 2014
The 5 Stages of Human Pregnancy:
Human pregnancy has 5 stages. The first stage is Ovulation, where a
mature egg is released from the Ovary and is sent down the Fallopian
Tube. The lining of the Uterus will have thickened to prepare for a
fertilized egg. It is during this stage that the egg can be fertilized by a
sperm cell. The next stage of human pregnancy is Fertilization, where a
sperm cell has made its way to an egg cell, burrowed into the egg, and
the egg has changed so that no other sperm can enter the egg. It is at this
stage that all of the genes of the baby are set. The next stage comes 3-4
days after fertilization where the dividing cells of the embryo form a
circular shape and is now called a Morula. This third stage is referred to
as the Morula Stage. After the Morula stage and approximately 5 days
after fertilization comes the Blastocyst stage. In this stage the morula
enters the uterus and develops a fluid-filled cavity and is now called a
Blastocyst. Inside the blastocyst, cells in one region group together to
form an inner mass that will become the Embryo eventually. The final
stage is Implantation. In this final stage, the blastocyst will attach to the
lining of the uterus where it will eventually become an Embryo, then a
Fetus, and eventually a baby.
The 3 Germ Layers In The Development Of An Embryo:
There is the Ectoderm which will eventually develops into the Central
Nervous System, the enamel of the teeth, The Peripheral Nervous
System, and the nails and hair. There is the Mesoderm which will
eventually develop into connective tissue, cartilage, bone, muscles, the
heart, the reproductive organs, the kidneys, and the spleen. Finally, there
is the Entoderm which will eventually develop into the lining of the
gastrointestinal and respiratory tracts, the tonsils, the liver, the thyroid,
the pancreas, and the lining of the bladder and urethra.
4 Important Tissues That Develop: