A1 Neural Development

Question 1

What is the name of the formation of the neural tube in chordates?

Answer 1

Neurulation

Question 2

What happens in Neurulation?

Answer 2

1. The Notochord signals the Ectoderm to infold, creating the neural tube.
2. The neural tube then elongates.

Question 3

What causes Spina Bifida?

Answer 3

The neural tube doesn’t completely close in one place.

Question 4

How are neurons produced?

Answer 4

During neurogenesis, by differentiation of multipotent cells, called progenitor cells, in the neural tube.

Question 5

What is the name of the cells that provide physical and nutritional support for neurons? Where do they come from?

Answer 5

Glial cells, they also come from progenitor cells

Question 6

Via which 2 processes can immature neurons migrate to their final position?

Answer 6

1. Glial guidance:
   -> Glial cells provide a network along which neurons travel
2. Somal translocation
   -> Neuron extends its axons and the soma travells along one of them and once arrived, pulls the axons back in.

Question 7

How long do neurons live? How easily can they be re-generated?

Answer 7

Most live for a lifetime, and they are unable of regeneration (a few in brain regions can do that though).

Question 8

What do immature neurons consist of only?

Answer 8

The soma (nucleus and cytoplasm)

Question 9

How do the axons and the dendrites grow of an immature neuron? How is the direction controlled?

Answer 9

Chemical stimuli are released from surrounding cells. Some are chemoattractants and some are chemorepellants.

Question 10

Can axons extend beyond the neural tube and reach other parts of the body (peripheral nervous system)?

Answer 10

Yes

Question 11

Define a synapse.

Answer 11

A junction at which a neuron transmits a signal to another cell

Question 12

In which forms are signals transmitted in synapses?

Answer 12

Mainly chemical, but also some are electrical.

Question 13

What are typical synapses in the central nervous system?

Answer 13

Neuron-Neuron, they can be axon-axon, axon-soma, axon-dendrite, dendrite-dentrite (anything, really)

Question 14

What are synapses in the peripheral nervous system?

Answer 14

Neuron-muscle,
neuron-gland,
Neuron-capillary (to secrete smth)

Question 15

What is pruning?

Answer 15

Axons of neurons are removed and synaptic connections are eliminated, if the synapse is not used.

Question 16

What is neuroplasticity?

Answer 16

capacity of nervous system to change and rewrite synaptic connections

Question 17

How is the adaptive responsiveness of neuroplasticity achieved? Through which 2 things?

Answer 17

1. Rerouting
   -> New connections are made, which creates alternative neural pathways
2. Sprouting
   -> Growth of axons and dendrites makes new neural connections

Question 18

Define a stroke.

Answer 18

Sudden death of brain cells due to inadequate blood flow

Question 19

What are the 2 types of strokes?

Answer 19

1. Ischemic stroke
   -> clot in blood restricts oxygenation to a certain region in the brain
2. Hemorrhagic stroke
   -> ruptured blood vessel causes bleeding

Question 20

What are the implications of a stroke?

Answer 20

Neural connections in the region are lost, but the healthy regions might adopt the functions of the dead region, so the symptoms could only be temporary. This is due to neuroplasticity.