Abnormalities (not systems) Flashcards
2 abnormalities related to gastrulation ?
- caudal dysgenesis (sirenomelia)
- sacroccygeal teratomas
caudal dysgenesis (sirenomelia) = insufficient …1… is formed in the …2… region of the embryo resulting in abnormalities in the …3.. limbs and ..4… system
- mesoderm
- caudalmost
- lower
- urogenital
sacrococcygeal teratoms = ..1… that occur when reminants of the …2… persist in the ..3… region (most common ..1… in newborns )
- tumour
- primitive streak
- sacrococcygeal
Fertilisation abnormalities ?
- dizygotic twinning
- monozygotic twinning
What’s the difference between dizygotic twinning and monozygotic twinning ?
- Di = fraternal , non-identical, arise from SEPARATE fertilisation events involving 2 separate oocyte & spermatozoa
- mono = identical , SINGLE fertilisation event , so share same genome
Abnormalities that can happen during week 2 (implantation and formation of bi-laminar embryonic disc) ?
- abnormal implantation - ectopic pregnancy
- molar pregnancy - hydatidiform mole
Abnormal implantation : ectopic pregnancy is implantation that occurs in … ?
uterine tube or outside the uterus (external surface of uterus, ovary, bowel, GI tract, peritoneal wall)
When does molar pregnancy- hydatidiform mole occur ?
only the trophoblast layers of the embryo proliferate and not the epiblast and as a result no embryo develops
neural tube defects (NTDs) occur when ?
neural tube closure fails to occur
What are the 2 neural tubes necessary to know ?
- anencephaly
- spina bifida
When does anencephaly occur ?
when the neural tube fails to close in the cranial region and as a result most of the brain fails to form
When does spina bifida occur ?
when neural tube fails to close anywhere from the cervical region caudally
most common site to occur is the lumbosacral region
50-70% NTDs can be prevented by daily intake of vitamin folic acid
