Embryo and Foetus Development Flashcards
1
Q
What is a teratogen?
A
An agent or factor that causes malformation of an embryo
2
Q
What are some environmental teratogens?
A
- thalidomide
- radiation
- alcohol
- drugs
- smoking
- poisions
- infections
3
Q
What are some genetic factors that can affect a foetus?
A
- chromosomal abnormalities
- mutant genes
- maternal age
4
Q
What is achondoplasia?
A
a dominant inherited abnormality that converts cartilage to bone
5
Q
When is the foetus not susceptible to teratogens?
A
between weeks 1-2
6
Q
When can spontaneous abortions occur?
A
Between weeks 1-2
7
Q
When do major congenital abnormalities occur?
A
Weeks 3 -8
8
Q
When do functional defects and minor abnormalities occur?
A
Weeks 9-38
9
Q
What structures does the ectoderm form?
A
- CNS
- PNS
- sensory apparatus of the ear, nose, eye
- epidermis, hair and nails
- subcutaneous glands
- mammary glands
- pituitary gland
- enamel of the teeth
10
Q
What does the mesoderm form?
A
- vertebral column
- dermatomes
- myotomes
- urogenital structures
- peritoneal, pleural and pericardial lining
- hemopoietic stem cells
11
Q
What does the endoderm form?
A
- GI tract
- epithelial lining of respiratory tract, urinary bladder and urethra
- tympanic cavity and auditory tube
- parenchyma of thyroid, parathyroids, liver and pancreas
12
Q
When do neural tube defects occur?
A
Weeks 3-16
