Embryology is the study of the complex process of development from a single cell to a baby. It includes investigations of the molecular, cellular, and structural factors that contribute to organism formation. The first 8 weeks of human development is called embryogenesis, where organs form. From then until birth is the fetal period. Studying causes of birth defects is called teratology. There are approximately 23,000 genes in the human genome, but gene expression is regulated at several levels, including transcription, messenger RNA, and translation, which results in over 5 times as many proteins. Organ formation involves induction, where one group of cells causes another to change fate, and competence, the ability to respond. Many interactions occur between epithelial and me

1. Introduction to Embryology
Themba Hospital FCOG(SA) Part 1 Tutorials
By Dr N.E Manana

2. Embryology
• Complex phenomena
• From a single cell to a baby
• The field includes investigations of the molecular, cellular, and
structural factors contributing to the formation of an organism
• The study of embryology and fetal development is an important topic
for all health care professionals

3. Embryology
• The first 8 weeks of human development is called the period of
embryogenesis AKA organogenesis
• The period from that point on until birth is called the fetal period
• The study of causes for birth defects is called teratology.
• Monitoring cell fates with different techniques provides valuable
information about the origins of different organs and tissues

5. Molecular regulation
• There are approximately 23,000 genes in the human genome
• Because of various levels of regulation, however, the number of proteins
derived from these genes is 5x more
• Gene expression can be regulated at several levels:
1. Transcription (Head office)
2. messenger RNAs (Message)
3. Translation (Factory)
4. Protein modification (Distributor)

6. Gene
transcription

7. Genes

8. RNA polymerase

9. Organ formation
• One group of cells or tissues causes another set of cells or tissues to change their
fate, a process called induction
• The capacity to respond to such a signal is called competence
• Many inductive interactions occur between epithelial and mesenchymal cells and are
called epithelial– mesenchymal interactions (liver, pancreases, limbs, vagina ect)
• The diffusible proteins responsible for paracrine signalling are called paracrine factors
or growth and differentiation factors (GDFs).

10. The four groups of GDFs include the
Fibroblast growth factor (FGF) important for
angiogenesis, axon growth, and mesoderm
differentiation .
WNT involved in regulating limb patterning,
midbrain development, and some aspects of
somite and urogenital differentiation among
other actions .
Hedgehog involved in several
developmental events including limb
patterning, neural tube induction and
patterning, somite differentiation, gut
regionalization, and others ,
and
Transforming growth factor-b (TGF-b)
families, neurotransmitters, such as
serotonin (5HT) and norepinephrine, also
act through paracrine signaling, serving as
ligands and binding to receptors to produce
specific cellular responses

11. Thank you