Principles of Neuroscience Lecture 4, Development of the nervous system

Question 0

From which cells does the neural tube form?

Answer 0

Neural plate cells form a layer on the ectoderm

Question 1

What are the layers in an embryo?

Answer 1

Trilaminar embryo:
Endoderm
Mesoderm
Ectoderm

Question 2

Describe the process of neurulation

Answer 2

The neural plate cells on either side of the primitive streak rise up and fuse at the top, forming a tube. This tube is called the neural tube. This goes on to form the spinal cord.

Question 3

What disorders can occur with neurulation, and how do they arise?

Answer 3

When the neural tube does not close up all the way up the spine.
This causes severe disorders such as:
Spina bifida (lumbar region)
Anencephaly (head)

Question 4

Describe the sections that the developing brain forms

Answer 4

Prosencephalon: forebrain
Mesencephalon: midbrain
Rhombencephalon: hindbrain
Caudal neural tube: spinal cord

Question 5

Describe the further segmentation of the prosencephalon

Answer 5

Telencephalon

Diencephalon

Question 6

Describe the further segmentation of the rhombencephalon

Answer 6

Two greater sections :
Myloencephalon
Metencephalon

7 sections all up

Question 7

What does the spinal cord form out of?

Answer 7

The caudal neural tube

Question 8

What is the name for the cells present at the top of the neural tube during development?
What is their function?

Answer 8

Neural crest cells. These cells migrate and go on to form many important cell types

Question 9

What is Somite?

Answer 9

Developing muscle and bone

Question 10

Describe the process of neural crest migration

Answer 10

Neural crest cells follow specific paths through the embryo

• under the skin to form the dorsal root ganglia
• through the Somite to form sympathetic ganglia

Eg. Innervation of the gut; enteric nervous system

Question 11

How does the cortex / cells of the brain form?

Answer 11

It starts with the neuroepithelium that is one cell thick.

This neuroepithelium adds cells that migrate away to form the cortex.

Question 12

What is the ventricular zone?

Answer 12

Down the bottom, where neurons are being born. Stem cells are here

Question 13

What are radial glia?

Answer 13

Their processes act as a guide along which neurons migrate down to form the cortex.

Question 14

What does the notochord go on to form?

Answer 14

The centre of the vertebral body

Question 15

What is sonic hedgehog?

Answer 15

Chemical that sets up a gradient and thus polarity in the neural tube, indicating where neurons should grow.

Question 16

Describe the process of axonal growth

Answer 16

Axons aren’t present when the neuron first develops

Question 17

What are growth cones made out of?

Answer 17

They are a dynamic cytoskeleton structure

Question 18

How to growth cones know where to go?

Answer 18

Chemical gradients steer the movement