Chapter 12: Conception and Prenatal Development: Developmental Stages Flashcards
Head large
5 weeks
Large head at beginning but body grows faster
9-12 weeks
CNS developing
3 weeks
Translucent skin
21-24 weeks
Zygote secretes hCG
0-2 weeks
Heart starts beating, continued development
5 weeks
Fingers and toes well defined
8 weeks
Implantation complete
2 weeks
Neural tube closes
4 weeks
Early heart development
3 weeks
Blood formation shifts to spleen
10-12 weeks
External genitalia begin to differentiate
8 weeks
Blood formation primarily in liver
6 weeks
Usually positions to head down
25-28 weeks
Nutrition provided by conceptus ball
0-2 weeks
Zygote division
0-2 weeks
Heart is prominent with final 4 chambers
6 weeks
Fetus moves but mother cannot feel
9-12 weeks
4-chamber heart begins
4 weeks
Eyes, ears, nose widely separated
6 weeks
Blood formation shifts to bone marrow
25-28 weeks
Movements strengthen and mother may feel them (quickening)
13-16 weeks
Can see heart beating in transvaginal ultrasound
6 weeks
Gains weight
25-28 weeks
Embryo resembles C shape
4 weeks
Growth and refinement of all systems
7-8 weeks
More subcutaneous fat
29-32 weeks
Surfactant
24 weeks
Definite human form
8 weeks
Development of vernix caseosa, lanugo, brown fat
17-20 weeks
Growth rate slows
33-38 weeks
Embryonic disk develops germ layers
3 weeks
