This is a page from genefaith.org created by Andrew J. Palmer 
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Human Development Chart                        

sperm & ovum form

Zygote - single cell capable of growth into a human being

zygote

lasts 30 hours, then makes first division

morulla or blastula

up 5days

ball of undifferentiated totipotent cells

Blastocyst

by day 5

Hollow Ball of cells, external and internal different. ca. 100 cells inner 50 are pleuripotent stem cells. External will become placenta, internal will become embryo

day 7 - 9

Blastocyst implants in wall of uterus
(55% of Zygotes never reach this stage.)

day 14 - 16

Blastocyst develops line of dark cells down centre that will become the spinal chord. Real differentiation has begun.

Embryo

day 14
to week 8

Embryonic phase:
gastrula

day 30

Lengthens and differentiates into
ecto-, meso-, & endo derm

Embryonic phase ends

week 8

At this point enough development to call a foetus. All organs and structures found in a newborn infant are now present.

foetus

week 9- 12

Major organs have begun to develop. Recognisably human, but cannot survive outside the womb.
15 % of pregnancies miscarry during weeks 4-12

foetus

week
13 - 16

About 6 inches long

foetus

week 20

Reaches about 8 inches long.

foetus

week 24

About 11 inches long and weighs about 1lb 10 oz.

foetus

weeks 29 - 39

Most healthy foetuses delivered during this period survive, earlier ones may need mechanical help to survive.

birth of baby

week 39

infant

0-5 yrs

Baby
Toddler
Infant
dependent human life

child

8 - 11 yrs

Capable of independent survival

adult human life

18+ yrs

This is a page from genefaith.org created by Andrew J. Palmer 
genetics home    site home