56) An infant is born anencephalic. He presents without both a | Anatomy embryology histology videos & books

56) An infant is born anencephalic. He presents without both a forebrain and a cerebrum. The remaining brain tissue is exposed, not covered by bone or skin. The infant is blind, deaf, unconscious, and unable to feel pain. Because the infant has a rudimentary brainstem, reflex actions such as respiration (breathing) and responses to sound or touch occur. However, the lack of a functioning cerebrum permanently rules out the possibility of ever gaining consciousness. Anencephaly is the result of a defect in which of the following?