Embryology Flashcards
Terminology of utero development: 0-3 weeks
- conceptus/embryo
Terminology of utero development: 3-8 weeks
- embryonic period
Terminology of utero development: 9-40 weeks
-fetal period
What are the 6 phases of embryogenesis?
- gametogenesis
- fertilisation
- cleavage
- gastrulation
- formation of a body plan
- organogenesis
Explain gametogenesis
- formation of gametes
- a gamete is a cell with a complement of 23 chromosomes
Process of the formation of male gametes
- spermatogenesis
Process of the formation of female gametes
- oogenesis
Explain the process of fertilisation
- union of gametes
Explain the process of cleavage
- period of rapid cell division
- rapid mitotic cell division with no increase in size
Explain the process of gastrulation
- formation of the germ layers
What are the names of the 3 layers created during gastrulation?
- ectoderm
- mesoderm
- endoderm
What happens during the formation of the body plan?
- embryonic folding
Explain the process of organogenesis
- formation of organs and organ systems
What occurs during the Foetal period?
- growth and weight gain
What does the primary process of induction represent?
- ability of one cell type to cause another to differentiate
What does epigenetic mean?
- preferential expression of either the maternal of parental copy of a gene
What is fertilisation?
- sperm binds to the glycoprotein –> zona pellucida
- acrosomal enzymes of the sperm breaks its way into the egg
- egg and sperm plasma fuse
What does sperm entry into the zona pellicuida trigger?
- triggers the end of meiosis 2 and causes the release of cortical granules by the oocyte
Where does fertilisation normally occur?
- the ampulla of the uterine tube
What is cleavage?
- the zygote undergoes many mitotic divisions to divide the egg into daughter cells –> blastomere
Up to 8 cells in the zona pellicuida, they are all____
- totipotent
What is mosaicism?
- individuals with 2 or more cell lines with different chromosome complements
Morula is the name given when there are more than __ cells
- 16+ blastomeres
What day does implantation normally occur, and where?
- day 6
- posterior or anterior wall of the uterine wall
What 2 layers is the bilaminar embryo made up of?
- epiblast
- hypoblast
What is an ectopic pregnancy?
- implantation outwit the uterus
what week does the primative streak form?
- week 3
Explain the process of gasturlation
- movement of epiblast through the primitive streak
- body axis formed
hypoblast cells are replaced by what?
- definitive endoderm
The epiblast of the bilaminar embryo becomes what in the formation of a triliminar?
- ectoderm
What are the 3 layers of the trilaminar disk?
- ectoderm
- mesoderm
- endoderm
What does the ectoderm become?
- dermis
- skin
- nails
What does the mesoderm become?
- axial skeleton
- organs
- urogential
What does the endoderm become?
- lining of the :
- resp tract
- GI tract
