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7 1/2 week embryo, 7.5 week embryo, seven and a half week embryo

Interactive Prenatal Development Timeline

[All ages refer to time since fertilization] [Features] [Help] [Tutorial]   [Print preview] [PDF]

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Beginner


BODY SYSTEMS SELECTION MENU
Nervous System Cardiovascular Muscular Early Events
Special Senses Respiratory Skeletal General
Blood & Immune Gastrointestinal Endocrine Growth Parameters
Skin Renal/Urinary Reproductive Movement
 




Go to Weeks:
0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 10-11 11-12 12-16 16-20 20-24 24-28 28-32 32-36 36-38

Unit 1:   The First Week
     
   
Unit 3:   2 to 3 Weeks
     
   
Unit 5:   4 to 5 Weeks
     
   
Unit 7:   6 to 7 Weeks
     
   
Unit 9:   8 to 9 Weeks
     
   
Unit 11:   10 to 11 Weeks
     
   
Unit 13:   3 to 4 Months
     
   
Unit 15:   5 to 6 Months
     
   
Unit 17:   7 to 8 Months
     
   
Unit 19:   9 Months to Birth
     
   
Fertilization
Play Movie - Cell Division
Week 1 ends
Play Movie - 1 to 2 weeks, implantation and HCG
Week 2 ends
Play Movie - 2 to 3 week embryo, amnion, germ layer
Week 3 ends
Play Movie - 3 to 4 week embryo, folding of the embryo
Week 4 ends
Play Movie - 4 to 5 week embryo, The Heart in Action
Week 5 ends
Play Movie - 5 to 6 week embryo, hand plates develop
Week 6 ends
Play Movie - 6 to 7 week embryo, hand movement
Week 7 ends
Play Movie - 7 to 8 week embryo, fingers, toes
Week 8 ends
Play Movie - 8 to 9 week fetus, reflexive movement
Week 9 ends
Play Movie - 9 to 10 week fetus, sucking, swallowing
Week 10 ends
Play Movie - 10 to 11 week fetus, eyes roll, yawns
Week 11 ends
Play Movie - 11 to 12 week fetus, nails, fingerprints
Month 3 ends
Play Movie - 3 to 4 month fetus, the rooting reflex
Month 4 ends
Play Movie - 4 to 5 month fetus, bronchial tree
Month 5 ends
Play Movie - 5 to 6 months fetus, responds to sound
Month 6 ends
Play Movie - 6 to 7 month fetus, response to light
Month 7 ends
Play Movie - 7 to 8 month fetus, behavioral states
Month 8 ends
Play Movie - 8 to 9 month fetus, firm hand grasp
Month 9 ends
Play Movie - 9 months to Birth, ready for Birth
Birth
169 events on this timeline
Click any picture to see more!
Unit 2:   1 to 2 Weeks
     
   
Unit 4:   3 to 4 Weeks
     
  • (3 weeks, 1 day):
  • RespiratoryRespiratory outgrowth
  • CardiovascularCirculatory system function begins
  • CardiovascularHeart begins beating
  • CardiovascularTubular heart begins folding
  • CardiovascularUmbilical arteries
  • CardiovascularUmbilical veins (right and left)
  • Early EventsBody cavities
  • (3 weeks, 3 days):
  • GastrointestinalLiver
  • GastrointestinalMembrane between future mouth and throat
  •          may begin to rupture
  • (3 weeks, 5 days):
  • GastrointestinalFirst part of pancreas
  • RespiratoryLung bud
  • CardiovascularDescending aorta
  • Nervous SystemLowermost spinal cord formation begins
  • Nervous SystemNeural tube closes (lower back)
  • Early EventsUpper limb primordium at level of
  •          somites 8 to 10
  • GeneralProgressively C-shaped embryo
  • (4 weeks):
  • SkinSkin is so thin, you can see through it!
  • GastrointestinalEsophagus primordia
  • GastrointestinalPancreas: Ventral pancreas
  • GastrointestinalPharynx
  • GastrointestinalSmall & large intestines
  • RespiratoryLungs begin filling chest cavity
  • RespiratoryTrachea
  • CardiovascularCirculatory system "well established"
  • CardiovascularFunctioning two-chamber heart
  • CardiovascularHeart rate (about) 113 beats/min
  • Nervous SystemFourth ventricle
  • Early EventsCervical flexure
  • Early EventsLimb buds - the first sign of arms and
  •          legs
  • Early EventsUmbilical cord emerging
  • Early EventsUpper and lower limb buds
   
Unit 6:   5 to 6 Weeks
     
   
Unit 8:   7 to 8 Weeks
     
   
Unit 10:   9 to 10 Weeks
     
   
Unit 12:   11 to 12 Weeks
     
   
Unit 14:   4 to 5 Months
     
   
Unit 16:   6 to 7 Months
     
   
Unit 18:   8 to 9 Months
     
  • (35 weeks):
  • MuscularFirm grip
  •  
  • (36 weeks):
  • GeneralBrain weight 300 grams
   


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