Congenital defects and human embryology Flashcards
What percentage of life births have some congenital defect?
20
Name some causes of congenital defects?
- No known cause
- Genetic
- Drug use
- Environmental
How does the drug accutane cause congenital defects?
Contains vitamin A which is fat soluble so can accumulate in the body. Toxic especially to developing foetuses
When do most major congenital defects occur?
First four weeks
How would you classify a major/ minor congenital defect?
Major: abnormality requiring medical/ surgical intervention
Minor: abnormality requiring no severe intervention and causing minor handicap
What is anencephaly
Without a skull
Skull bones don’t form so cerebral cortices exposed
Usually incompatible with life
What is hypospadias?
Penis not fused
Classified as major defect but not life threatening
Which is cryptorchidism?
Testes not in scrotum at birth
Minor defect
What is holoprosencephaly?
Abnormal forming/ incorrect size midline structures
What is congenital diaphragmatic hernia?
Gastrointestinal system enters thorax, usually on left side of diaphragm.
What is gastroschisis?
Body wall not closed, so intestine external.
Where does fertilisation occur
Ampulla of uterine tube
What happens in week 1 of development
Going through oviducts
1 cell–> morula (ball of cells) in first 4.5-5 days
Becomes a blastocyst when in uterus, before implantation
What day does implantation usually occur?
Day 6
What happens in week 2?
Differentiation of trophoblast, embryoblas and formation of 2 cavities
