Chapter 5 Development of the Brain Flashcards
• Is the production of new cells, early in development the cells lining the ventricles of the brain divide. Some cells remain where they are (Stem Cells) continuing to divide and others become primitive neurons and glia that begin migrating to other locations
Proliferation
• After cells have differentiated as neurons and glia, they _______ Some neurons _______faster than others and a few of the slowest do not reach their final destination until adulthood.
Migration
• At first, a primitive neuron looks like any other cell; gradually the neuron ________forming its axon and dendrites (AXON FORMS FIRST).
Differentiates
A later and slower stage of neuronal development ________; the process by which glia produce the insulating fatty sheaths that accelerates transmission in many vertebrate axons.
Myelination
The FINAL stage, the formation of the synapses.
Synaptogenesis
build way to many connections and have to prune some back.
Synapse Pruning
In 1924, he conducted an experiment in which he grafted an extra leg to the salamander and then waited for axons to grown into it. After the axons reached the muscles, the extra leg moved in synchrony with the normal leg next to it.
Paul Weiss
Experimented with how sensory neurons found their way to correct targets. Cut the optic nerve of newts; found that axons grew back to their original targets, even though the connections were inappropriate to their new positions.
Robert Sperry
o In the development of the nervous system we start with more neurons and synapses than we can keep. Synapses form with only approximate accuracy, and then selection process keeps some and rejects others.
Neural Darwinism
Discovered that the muscles DO NOT determine how many axons form, they determine how many SURVIVIE.
Rita Levi Montalcini
• When one of the neurons form the sympathetic nervous system forms a synapse onto a muscle, the muscle delivers a protein called _____ that promotes the survival and growth of the axon.
Nerve Growth Factor
Cell suicide; if its axon does not make contact with an appropriate postsynaptic cell by a certain age, the neurons kills itself.
Apotisis
A chemical that promotes the survival and activity of neurons.
____ are essential for growth of axons and dendrites, formation of new synapses, and learning,
Neurtrophin
What are the chemicals the guide neural migration ?
immunoglobulins and chemokines
What forms first, the axon or dendrites?
axon
