Development of a fetus Flashcards
What is gestation
In all mammals, it is the time in the uterus from fertilisation until birth. In humans this is known as pregnancy.
How long does pregnancy last
It takes around 9 months (40 weeks) for a fertilised egg to develop into a baby.
Alcohol and smoking when pregnant
Smoking can cause a baby to be born early.
Alcohol can cause problems in the development of the baby’s brain.
Where does a baby grow
A baby develops in the uterus, after eight weeks it is known as a fetus.
How does a baby grow
The fetus receives nutrients and oxygen from its mother through her blood.
What are the 3 important structures inside the uterus
Placenta
Umbillical Cord
Fluid Sac
What does the Placenta do
substances pass between the mother’s blood and the fetus’s blood, it acts as a barrier stopping infections and harmful substances from reaching the fetus.
What does the Umbillical cord do
This connects the fetus to the placenta
What does the fluid sac do
This acts as a shock absorber, protecting the fetus from any bumps.
How does a baby develop - 1 week
just a dot - cells beginning to specialise
How does a baby develop - 4 weeks
3mm long - spine & brain forming, heart beat
How does a baby develop - 9 weeks
3cm long - tiny movements, lips and cheeks sense touch, eyes and ears forming
How does a baby develop - 12 weeks
7cm long - fetus uses its muscles to kick, suck, swallow and practise breathing
What happens during birth
Mother’s cervix relaxes and the muscles in the wall of the uterus contracts, this gradually pushes the baby out of the vagina. The umbillical cord is still joined to the mother and needs to be cut - the placenta is then pushed out.
