Chapter6 Flashcards
(104 cards)
How do neurons develop?
Through processes in embryo growth
What initiates the formation of immature nerve cells?
Signaling molecules
What is the stage after the formation of immature nerve cells?
Cell division (proliferation)
What happens during cell division?
Increase brain cells by billions
What occurs during migration?
Neurons travel to destinations
What do surrounding tissues produce to influence cell type development?
Signals
What process occurs when mesoderm signals induce ectoderm cells?
Neural induction
What are the basic categories of nerve tissue?
Neurons or glia
What determines the fate of a developing cell?
Proximity to signaling molecules
What is sonic hedgehog?
A signaling molecule
What cells are formed with high sonic hedgehog exposure?
Specialized glia
What cells are formed with medium sonic hedgehog exposure?
Motor neurons
What cells are formed with low sonic hedgehog exposure?
Interneurons
Do interneurons relay messages to muscles?
No
Is the mechanism of molecular signaling similar in different species?
Yes
What type of cells give rise to neurons?
Neural stem and progenitor cells
What do early divisions of neural stem cells result in?
Two identical daughter cells
What process allows rapid brain growth?
Neurogenesis
What happens to neural stem cells after early development?
Few remain
Where is adult neurogenesis limited?
Memory regions
What may cause microcephaly?
Protein defects
What is characterized by severe reduction in brain size?
Disorder causing neurological disabilities
What disorder is associated with excessive proliferation of brain cells?
Megalencephaly
What happens to new neurons after neural induction and proliferation?
They migrate