試題詳解

61. Which of the following best describes how an axon grows toward its target cell?
(A) The axon grows in a direct path, attracted by signal molecules released by target cells.
(B) Cells along the growth path release signal molecules that either attract or repel the axon, and the interaction of CAMs on the growth cone and neighboring cells may provide tracks that guide axon growth.
(C) Nerve growth factor released by astrocytes stimulates a neural progenitor cell to differentiate into a neuron, whose axon then grows toward an increasing concentration of signal molecules.
(D) The axon produces growth-promoting proteins only in its growth cone, causing the axon to grow in an outward direction toward its target cells.
(E) Glia first migrate to the target cells, leaving a trail of CAMs along the path that the growth cone of the axon follows.