A1 Neural development

Option A1. Neural
Essential idea: Modification of neurons starts in the earliest stages of embryogenesis
and continues to the final years of life.
A.1.U1 The neural tube of
embryonic chordates is
formed by in folding of
ectoderm followed by
elongation of the tube
A.1.U2 Neurons are initially
produced by differentiation in the
neural tube
A.1.U3 Immature neurons migrate to
a final location
A.1.U4 An axon
grows from each
immature neurons
in response to
chemical stimuli
A.1.U5 Some axons extend beyond the neural tube to reach other parts of the body
A.1.U6 A
neuron forms
A.1.U7 Synapses that are
not used do not persist
A.1.U8 Neural
pruning involves the
loss of unused
A.1.U9 The plasticity of the
nervous system allows it to
change with experience
A.1.A1 Incomplete closure of the
embryonic neural tube can cause
spina bifida
A.1.A2 Events such as
strokes may promote
reorganization of brain
What conclusion
regarding the effect of
post-rehabilitation of
stroke survivor can you
make using the fMRI
images below?
Place your mouse
pointer on the images to
view the conclusion
A.1.S1 Annotation of a diagram of
embryonic tissues in Xenopus, used
as an animal model, during
Can you identify
the Xenopus embryonic tissues in the
electron micrograph below
Place your mouse pointer on ECG to view tissue labels