A.1 Neural Development

Question 1

What is the spina bifida

Answer 1

An incomplete closure of the embryonic neural tube

Question 2

What are the two different types of nerve cells

Answer 2

• glial cells
• neurones

Question 3

What are the features of glial cells

Answer 3

• roughly 90% of nerve cells in the brain are glial cells
• provide physical and nutritional support for the neurons

Question 4

What are the features of neurones

Answer 4

• specialised nerve cells that conduct messages
• sensory, relay or motor neurons

Question 5

What is the purpose of neurulation

Answer 5

the formation of the brain and the spinal cord

Question 6

Why do immature neurones migrate

Answer 6

to adopt precise final positions that allow for the formation of neural networks/pathways

Question 7

Where are neurones produced/formed

Answer 7

through differentiation from the neural tube

Question 8

Outline axon growth in immature neurones

Answer 8

• Chemical stimuli determine the direction and length of the axon
• Axons grow out from each immature neurone
• Some axons extend beyond the neural tube to reach other parts of the body.

Question 9

What is a synapse

Answer 9

a structure that permits a neurone to pass an electrical impulse to another neurone

Question 10

Feature of developing neurones

Answer 10

they develop multiple synapses which allows more complex communication and increases neural networks/pathways

Question 11

What is neural pruning

Answer 11

It is the loss of unused neurones
- by removing excess axons and eliminating their synaptic connections

Question 12

Outline the importance of neural pruning

Answer 12

• This strengthening and weakening of certain neural pathways is central to the concept of how organisms learn
• Other synapses are not used as often and these connections are weakened and do not persist

Question 13

Outline neuroplasticity

Answer 13

• enables individuals to reinforce certain connections or circumvent damaged regions
• sprouting or re-routing

Question 14

Outline two methods of neurplasticity

Answer 14

sprouting: the growth of new axon or dendrite fibres to enable new neural connections to be formed
re-routing: re-establishing an existing nervous connection via an alternative neural pathway

Question 15

Brain injuries and neuroplasticity

Answer 15

During a stroke or disease, rearrangements in brain function involve changes in the connection between linked neurons (ex: re-routing and sprouting)