Principles of Embryology Flashcards
What is the first 3 weeks of life called
Conceptus
What is week 4-8 called
Embryo
What is week 9-birth called
Foetus
What occurs in gametogenesis?
Germ cell formation
Oogenesis to form the oocyte
Spermatogenesis to form the spermatozoa
What is fertilisation?
The fusion of the sperm and oocyte nucleus to form the zygote.
What is the name of the cell membrane of an oocyte?
Zone pellucida
What occurs during cleavage?
Period of rapid cell division but no size increase as the cells are contained within the zona pellucida
What name are the cells given at week 16+
Morula
What does the cell progress into after a morula?
Blastocyst
What is gastrulation?
Formation of germ layers
What are the three germ layers?
Ectoderm
Mesoderm
Endoderm
What is embryonic folding?
Formation of gut tube inside the skin/body wall
When does embryonic folding occur??
At about 4 weeks
What is organogenesis?
The formation of organs and organ systems
What are the main purposes of the foetal period?
To grow and gain weight Allow tissue maturation to occur allowing them to become functional Develop sexual differentiation Lay down bones Create connections in CNS
What are the anatomical planes in a foetus?
Superior becomes cranial
Inferior becomes caudal
Anterior becomes ventral
Posterior becomes dorsal
What are the primary processes in zygote development?
Cell division = increase cell numbers
Differentiation = specilaisation
Cell attachment = physical/functional linkages and formation of tissues
Apoptosis = programmed cell death
Induction = One cell causes another to differentiate
Cell migration = movement from one location to another
What are the secondary processes in zygote development?
Axis formation/polarity = cells learn which way is up and their position in relation to each other
Folding/rotation = entire embryo/structures give the embryo its 3D form. Allows the completion of complex organ structures
How is development controlled?
By:
Genetic, epigenetic (preferential expression of either maternal or paternal copy of gene) and environmental factors
