BIO 351 Exam 2 Diseases and Misc

situs inversus - "inverted position" -all organs are inverted in their localization left-right neural tube defects (NTDs) - -timing and localization of disruptions to neural tube closure can lead to a spectrum of NTDs -disruptions of neural tube closure can affect surrounding tissues such as somites, the embryonic precursors to the vertebral bones, leading to various disorders -2 types: 1. open NTDs 2. Occult (hidden) NTDs open NTDs - -anencephaly -encephalocele -myelomeningocele occult (hidden) NTDs - spina bifida occulta dysraphia (plural of dysraphism) - -group of congenital malformations involving defects in the skull and spinal columnn that are caused primarily by the failure of the neural tube to close during embryonic development -anencephaly -spina bifida open NTD - anencephaly - -results from severe, early failure of anterior neural tube closure open NTD - encephalocele - less severe than anencephaly and there can be a skin covering over the neural tube closure defect -doesn't allow skull to completely close out -brain leaks through holes but still have continuity of membrane open NTD - myelomeningocoeles - -failures of neural tube closure in spinal column closed NTD - spina bifida occulta - -hairy patch in lumbosacral region -skin covering area -hairy patch indicative of anomaly -craniorachischisis - completely open brain and spinal cord -iniencephaly - -occipital skull and spine defects with extreme retroflexion of the head