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Fertilization
The sperm and ovum combine to create a zygote. This happens in the fallopian tube. -
Period: to
Gestational Period
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Blastocyst Formation
At this point, the zygote has divided into a ball of cells which can be grouped into an inner core and an outer shell. The inner core will continue to develop into the feotus itself, while the outer shell will form membranes that will nourish the feotus. This is called a blastocyst. This is made from around a hundred cells. -
Implantation
The blastocyst implants into the endometrial lining of the uterus. (it will have left the fallopian tubes at this point.) -
Embryo
Blastocyst becomes embryo. Meaning cells have started to differentiate into specialised tissue cells. -
Yolk Sac Formation
The yolk sac serves as the source of nutrition for the feotus. It is the primative form of the curculatory system. It is essential as it is a replacement for internal circulation. WEEK 2 -
Systems Develop
The brain, spinal chord, heart and the gastrointestinal tract starts to develop. WEEK 3 -
Limbs
Limb buds are visible. WEEK 4-5 -
Eyes and Ears
Eyes and ears begin to form. -
Nervous System
The brain develops into five areas and some cranial nerves are visible. WEEK 4-5 -
Heart beats
The heard continues forming and now starts beating. Blood moving through main vessels. WEEK 4-5 -
Lungs Form
Lungs begin to form -
Brain Continuing to develop
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Longer Limbs and Digits Forming
The arms and legs have grown longer, and foot and hand areas can be distinguished. The hands and feet have fingers and toes (digits), but may still be webbed. WEEK 6 -
All Major Organs Starting to Develop
WEEK 7 -
Facial Features
Facial Features Continue to develop and ear ridge nearly finished forming. WEEK 8 -
Fetal Period
No longer considered an ambryo, but is called a feotus. -
Haematopoiesis
Red blood cells are produced in the liver. WEEK 9-12 -
Gender
Genitals appear well differentiated. -
Movement
The baby can make a fist with its fingers. -
The baby begins to make active movements.
The baby begins to make active movements, including sucking its mouth. WEEK 13-16 -
Hears
The baby can hear -
More Movement
The mother can feel the feotus move. -
Lots of hair
Hair covers entire body, and eyelashes and eyebrows form. -
Nails
Nails form on toes and fingers. -
More Hematopoeisis
Bone marrow begins to make blood cells. WEEK 20-22 -
Fat storage
Baby satrts storing fat. WEEK 21-23
