L5: Defects in Development Flashcards
Define morula
Embryo at early stage of embryonic development
Define blastocyst
Cluster of dividing cells made by fertilised egg (inner cell mass)
What is the lining that lines the blastocyst?
Trophoblast
3 germ layers
1) ectoderm
2) mesoderm
3) endoderm
When does the 3 germ layers arise from?
Gastrulation
What does ectoderm form?
- Skin
- Nervous system
What does mesoderm form?
- Muscle
- Skeleton
- Kidneys
- Reproductive system
What does endoderm form?
- Endocrine glands
- Lungs
- Liver
- Digestive tract
4th type of germ layer
The Neural Crest
Where do cells leave in the neural crest?
Neural tube
How do cells leave the neural tube?
Densely packed cell in the beginning
In order for cells to migrate out, they have to change their phenotype, becoming loosely packed cell
What do cells that leave the neural crest make?
1) Sensory neurons
2) Autonomic neurons
3) Enteric neurons
4) Schwann cells
5) Smooth muscle
Define angiogenesis
Process of new capillaries forming from pre-existing blood vessels
When does the heart already start beating ?
3 weeks
Are the 3 germ layers unipotent, multipotent or pluripotent?
Multipotent
Differentiate into multiple cell types
How is the multipotent neural crest generated?
Epithelial-mesenchymal transformation from the neuroectoderm
Which weeks does most organs develop within the embryonic period?
Weeks 3-8
Is inner cell mass unipotent, multipotent or pluripotent or totipotent?
Totipotent?
Give rise to any cell type
Is inner cell mass pluripotent, multipotent or unipotent?
Pluripotent
Give rise to several different cell types
2 major defects in development
1) Transposition of the great blood vessels
2) Diaphragmatic hernia
Minor birth defects
Tongue tie
Bilaterial cleft lip
Causes of human embryonic malformations?
- Unknown
- Genetic factors
- Environmental factors
- Inheritance
Example of chromosomal defects
Down’s syndrome
Define TORCH conditions
- Toxoplasma parasite
- Other viruses
- Rubella virus
- Cytomegalovirus
- Herpes simplex virus
