SNC 1D1
3.3 Pregnancy, Differentiation and Birth in Humans (pg 95)
1.Which development marks the change from an embryo to a fetus?
_________________________________________________________________________________________
_________________________________________________________________________________________
_________________________________________________________________________________________
2. Define the following terms.
gestation _________________________________________________________________________________
__________________________________________________________________________________________
differentiation _______________________________________________________________________________
__________________________________________________________________________________________
trimester ___________________________________________________________________________________
__________________________________________________________________________________________
fetus ______________________________________________________________________________________
__________________________________________________________________________________________
3. Briefly describe the changes that occur in each of the 3 trimesters of normal human gestation by completing the following
chart
trimester
one
two
three
duration (week
numbers)
major physical developments
size of fetus
4. Make a list of factors that can harm a developing embryo or fetus. Which of these factors are particularly dangerous at
specific periods?
_________________________________________________________________________________________
_________________________________________________________________________________________
_________________________________________________________________________________________
5. Explain the three changes in hormone levels that account for the onset of labour.
_________________________________________________________________________________________
_________________________________________________________________________________________
_________________________________________________________________________________________
6. Describe the three stages of birth by listing the major events that mark each and the duration of each stage.
_________________________________________________________________________________________
_________________________________________________________________________________________
_________________________________________________________________________________________
_________________________________________________________________________________________
_________________________________________________________________________________________
_________________________________________________________________________________________
From St. Andrews College web page