Chapter 2: Development of the Nervous System
Which of the following best describes the process of neural induction (NI)?
A. NI involves the release of morphogens by the notochord that inhibit bone morphogenetic proteins (BMP) signaling in the overlying ectoderm.
B. NI involves morphogens released by the neural plate to the underlying notochord.
C. In NI. morphogens stimulate the developing gastrula to form the 3 primary germ layers.
D. NI occurs following neurulation, during segmentation and flexure.
E. NI involves induction of the mesoderm to form neural mesoderm.
A. Neural induction occurs after gastrulation, when the notochord at the midline (and surrounding paraxial mesoderm) releases morphogens to the overlying ectoderm. These morphogens inhibit the BMP signaling pathway in the ectoderm and instruct the ectoderm to form the neural plate (neuroectoderm). Once the plate is formed, it undergoes neurulation followed by segmentation and flexure.
Which of the following best characterizes development of the neural tube?
A. Errors in neuronal and glial migration produce microcephaly.
B. Errors in proliferation and expansion of the neural tube produce neural tube defects.
C. It forms from the neural plate in the process of “neural flexure” following gastrulation.
D. It gives rise to the vast majority of neurons and glia of the central nervous system (CNS).
E. The lumen of the neural tube forms the meninges and blood supply of the brain and spinal cord.
D. Errors in neurogenesis and gliogenesis cause microcephaly. Errors in neuronal migration cause cortical malformations such as heterotopias. Neural tube defects result from errors in closing of the neural tube. The neural tube forms from the neural plate via the process of neurulation. The neural tube gives rise to almost all the neurons and glia of the CNS (a small number of neurons that end up in the CNS arise from placodes or neural crest). The lumen of the neural tube forms the brain ventricles and central canal.
Which of the following best describes regionalization of the neural tube during development?
A. The myelencephalon gives rise to the cerebellum.
B. The mesencephalon gives rise to the midbrain.
C. The telencephalon gives rise to the thalamus and hypothalamus.
D. The diencephalon gives rise to the forebrain.