THREE STAGES OF
PRENATAL DEVELOPMENT
4.1 THE DEVELOPING BABY
3 STAGES OF PRENATAL DEVELOPMENT
• Pages 99-104
• Read Introductory Paragraph
• Prenatal Development: The baby’s development
during pregnancy.
• “Pre” = before & “Natal” = birth
THE GERMINAL STAGE
• Read page 99
• Take Notes
THE GERMINAL STAGE
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Stage 1
Unborn baby called zygote (fertilized egg)
2 weeks
Cells dividing rapidly (in fallopian tube)
Zygote implants in thick uterine lining
Zygote size of head of a pin
THE EMBRYONIC STAGE
• Read page 100
• Take Notes
THE EMBRYONIC STAGE
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Stage 2
Unborn baby called embryo
3rd-8th week
Face, eyes, ears, limbs & bones formed
Internal organs & systems develop, but not function
Foundation
Heart, lungs, bones & muscles formed
Neural tube closes, brain & spinal cord forming
Critical stage for brain development
Mother must avoid hazards
THE EMBRYONIC STAGE
• Amniotic Sac: Bag filled with amniotic fluid which
baby floats in, cushion & protect baby
• Water breaks
• Placenta (chef): Tissue made of red blood cells
connected to uterus, gives baby nutrients & oxygen
• Umbilical cord (waiter): Tube that connects the
baby to placenta, carried nutrients & oxygen to the
baby & carries waste away from baby
THE FETAL STAGE
• Read page 101-104
• Take Notes
THE FETAL STAGE
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Stage 3
Unborn baby called a fetus
Longest stage
Begins 8th or 9th week – birth
Organs & Body Systems: continue develop & function
Quickening: 1st time a mother feels movement
Age of Viability: fetus could survive if born
Active, but then rest
5 senses start to work
Cough, sneeze, cry, hiccup, kick
Gain weight
Last month: get immunities from mother
Lightening: dropping of baby into birth canal