Stages Of Development Flashcards
Explain conception
This is when the head of a sperm penetrates the layers of the egg to fuse with the nucleus.
A single new cell is formed containing 46 chromosomes (23 from each parent) with all the genetic info to create a new life.
What happens at 5 weeks?
Growth is concentrated at the head because the brain is undergoing crucial and rapid development in order to effectively regulate the heart rate, blood circulation and other vital functions.
The heart begins to beat.
What happens at 12 weeks?
The foetus is fully formed.
Features become more recognised.
Practice breathing using amniotic fluid.
What happens at 20 weeks?
The foetus becomes more active.
The genitals have completely formed.
What happens at 24 weeks?
If the foetus was born at 24 weeks there is 50% and 70% chance of survival.
From this week onwards the foetus will gain around 90g a week in the womb.
What happens at 32 weeks?
The foetus is practicing all the skills needed to survive outside the womb.
Digestive system is fully functioning.
How long is the gestation period for a human?
40 weeks
Zygote
0-5 days
Blastocyst
5-14 days
What happens at 14 days?
The cells become specialised.
No genetic testing to take place after this.
Embryo
14 days - 8 weeks
Foetus
8 weeks onwards
