Developmental Disorders of CNS Flashcards
Nervous system develop from ____ germ layer.
ectoderm
Regionally thickened ectodermal germ layer =
neural plate
Gives rise to most of the PNS
Neural crest
Anencephaly =
Failure of closure of rostral part of neural tube
Absent cranial vault, forebrain –> incompatible w/ long-term postnatal life
Protrusion of brain and meninges through defect in skull.
Encephalocele
Herniation of spinal cord and meninges through defect in vertebral column.
Myelomeningocele
T/F: Myelomeningocele is incompatible w/ long-term postnatal life.
False.
Early surgical repair improves change of survival.
Which of the following is NOT one of the 3 vesicles that form from the neural tube? A. Mesencephalon B. Myelencephalon C. Prosecephalon D. Rhombencephalon
B. Myelencephalon and metencephalon is a subdivision of rhombencephalon.
Prosecephalon = forebrain Mesencephalon = midbrain Rhombencephalon = hindbrain
T/F: Mesencephalon divides into diencephalon and telecephalon.
False. These are subdivisions of prosecephalon (forebrain).
Mesencephalon does not subdivide.
Telecephalon becomes ____
cerebral hemisphere
Diencephalon becomes ____
thalamic structures
Mesencephalon becomes ____
midbrain
Metencephalon becomes ____
pons and cerebellum
Myelencephalon becomes ____
medulla oblongata
Complete failure of primitive forebrain to diverticulate into two telencephalic vesicles.
Holoprosencephaly
Which of the following is NOT a clinical presentation of Holoprosencephaly? A. Severe mental retardation B. Endocrine disorders C. Seizures D. Quadriparesis
B. Endocrine disorder is a presentation of Septo-optic dysplasia.
Defect in formation of midline structures of forebrain
Absence of septum pellucidum, optic nerve hypoplasia and pituitary hypoplasia.
Septo-optic dysplasia
Which of the following is NOT a clinical presentation of Septo-optic dysplasia? A. Blindness B. Mental retardation C. Endocrine disorders D. Seizures
D
Generation of neurons occurs from ___ to ___ months of gestation
2 - 5th
Volume of 1 cerebral hemisphere is much greater than normal due to error in control of brain cell proliferation on the affected side.
Hemimegalencephaly
Which of the following is NOT a clinical presentation of Hemimegalencephaly? A. Large heads B. Seizures C. Mental retardation D. Quadriparesis
D. Hemiparesis
Which of the following is FALSE about Lissencephaly?
A. It is the most severe neuronal migration disturbances
B. Cortical surface are broad and shallow
C. Microcephalic
D. Do not survive infancy
E. Intractable seizure, severely impaired psychomotor development
B. This is feature of Pachygyria. Lissencephaly is smooth and featureless.
T/F: Infants with pachygyria survive with severe focal seizures.
False. Survive with severe neurological impairment.
Broad, shallow and reduced in number as result of defective neuronal migration.
Pachygyria
