Practice 5 Embryology II
1. Describe the term “somite”. Explain, when do the somites first appear, in what numbers
and when do they disappear? How the number of somites relates to the age of embryo?
Describe the derivatives of somites.
2. Describe and graphically schematize the following structures: chorion laeve, chorion
frondosum, chorionic villi, decidua basalis, decidua capsularis, decidua parietalis. What
is the structure of tertiary chorionic villus?
3. Describe and graphically schematize human placenta, indicate its discoid shape
including size. Indicate pars materna, pars fetalis, intervillous space.
4. Summarize and where applicable also graphically schematize the normal position of
placenta and umbilical cord, as well as the principal abnormalities of placenta and
umbilical cord.
5. Draw a scheme describing development of dizygotic and monozygotic twins, and
indicate what fetal membranes are shared in individual scenarios.
6. Calculate fetal age according to rule of Haase for abortus of 10 and 40 cm in length.
7. Summarize fetal positions in uterus (situs, positio, habitus, presentatio). Identify the
physiological fetal position(s).
Recommended study materials: Presentations from practices and lectures, Atlas of Cytology
and Embryology (online), Langman’s medical embryology, Developing human.