Embryology - Principles Flashcards
From fertilisation to end of week three, what is the thing called?
Conceptus or embryo. Slide 5
What is the term to describe the conceptus during weeks 4 to 8?
Embryo. Slide 5
From week 9 till birth what is the embryo called?
Foetus. Slide 5
What is gametogenesis?
Germ cell formation. Slide 7
What is the formation of the oocyte and spermatoza called?
Oogenesis and spermatogenesis. Slide 7
What is a zygote?
The fertilised oocyte. Slide 8
What are corona radiate?
The support cells which surround the zona pellucida. Sperm cells are able to get through. Slide 8
What is the acrosome?
It is the apex of the sperm head which contains enzymes to break the zona pellucida down. Slide 8
What is cleavage?
Period of rapid cell division with no increase in size. Slide 9
What is the fertilised egg called up to 16+ cells?
A morula. Slide 9
In a blastocyst there are two different types of cells, what do they do?
One form a layer around the outer ring next to the zona pellucida and this makes the placenta. The other forms a small cluster of cells which is the inner cell mass. Slide 9
What does totipotent mean?
Any specialisation of cell. Slide 9
What are the 3 germ layers in an embryo?
Ectoderm, mesoderm and endoderm. Slide 10
What will each germ layer do in the embryo?
Ectoderm gives rise to skin and the endoderm forms the gut tube. Slide 10
What does embryonic folding mean?
Trying to make the embryo more 3D by folding and producing a “tube within a tube” where the gut tube is within a tube of skin. Slide 11
What does organogenesis mean?
Formation of organs and organ systems. Slide 12
What happens during the foetal period?
Growth and weight gain. Also the tissues become more mature and functional. Visible sexual differentiation and there are bones laid down so connections made in CNS. Slide 13
Why is terminology and landmarks different to those used in adult anatomy?
A the baby’s positioning in anatomical position is different and more curved round. Slide 14
What is the ventral part of the baby?
The anterior front part. Slide 14
What is the dorsal part of the baby?
The posterior back part. Slide 14
What are the primary processes of growing from embryo to foetus?
Cell division, differentiation, cell attachment, apoptosis, induction and cell migration. Slide 16+17
What does the cell division contribute to in the primary process of growth in the embryo?
Increase in number of cells. Slide 16
What does the differentiation contribute to in the primary process of growth in the embryo?
Specialisation, change in appearance and adoption of new functions. Slide 16
What does the cell attachment contribute to in the primary process of growth in the embryo?
Physical/functional linkages and formation of tissues. Slide 16
What does the apoptosis contribute to in the primary process of growth in the embryo?
Programmed cell dead when defining complex structures. Slide 16
What does the induction contribute to in the primary process of growth in the embryo?
Creates the ability of one cell type to cause another to differentiate e.g. using a proteins which causes a cell to react to it. Slide 17
What does the cell migration contribute to in the primary process of growth in the embryo?
Movement from one location to another. Slide 17
What are the two secondary processes?
Axis formation and folding/rotation. Slide 18+19
What does the axis formation contribute to in the secondary process of growth in the embryo?
Cells need to know where they are in relation to each other and the embryo as a whole. Slide 18
What does the folding/rotation contribute to in the secondary process of growth in the embryo?
Creates the entire embryo or structures within it creating the 3D form, e.g. formation of the heart as it starts as a simple tube and then is folded and rotated. Slide 19
How is development of the foetus controlled?
Genetically - gene expression and is tightly regulated.
Epigenetic - preferential expression of either maternal/paternal copy of a gene.
Environmental - however the foetus can’t really control how it responds to it. Slide 20
What is epigenetic control?
Genetic imprinting where genes are preferentially expressed from either the maternal or paternal copy, if a copy is deleted which is preferred, then mutations come about. Slide 21
