14) Steps in repair and regeneration of nervous tissue

Question 1

The “ability to change based on experience” refers to:

a) regeneration
b) plasticity
c) neurogenesis
d) chromatolysis
e) Wallerian degeneration

Answer 1

b - plasticity

Question 2

The “capability to replicate or repair oneself” refers to:

a) regeneration
b) neurogenesis
c) chromatolysis
d) Wallerian degeneration
e) plasticity

Answer 2

a - regeneration

Question 3

The “birth of new neurons from undifferentiated stem cells” refers to:

a) plasticity
b) Wallerian degeneration
c) chromatolysis
d) regeneration
e) neurogenesis

Answer 3

e - neurogenesis

Question 4

On an individual neuron level, what happens during plasticity?

Answer 4

sprouting of new dendrites, synthesis of new proteins, changes in synaptic contacts with other neurons

Question 5

Plasticity is driven by:

a) electrical signals
b) chemical signals
c) magnetic signals
d) a and c are true
e) a and b are true

Answer 5

e - both electrical and chemical signals

Question 6

New neurons arise (neurogenesis) in which part of the brain?

Answer 6

In the adult hippocampus, the area of the brain crucial for learning.

There is complete lack of neurogenesis in other regions of brain and spinal cord

Question 7

T/F

There is complete lack of neurogenesis in the brain and spinal cord

Answer 7

False -
There is NEARLY complete lack of neurogenesis in brain and spinal cord.

Neurogenesis occurs in the hippocampus

Question 8

T/F

Injury of the brain or spinal cord is usually permanent

Answer 8

True

Question 9

Nearly complete lack of neurogenesis occurs in most brain regions and in the spinal cord as a result of what two factors?

Answer 9

1) inhibitory influences from neuroglial (particularly oligodendrocytes)
2) absence of growth-stimulating cues that were present during fetal development

Question 10

Why is an injury to the brain or spinal cord usually permanent?

Answer 10

after axonal damage, nearby astrocytes proliferate rapidly, forming a type of scar tissue that acts as a physical barrier to regeneration.

Question 11

Most nerves in the PNS consist of processes that are covered with a ______

Answer 11

neurolemma

Question 12

Damage and repair in the PNS - when will axons and dendrites associated with a neurolemma undergo repair?

Answer 12

1) if cell body is intact
2) if Schwann cells are functional
3) if scar tissue formation does not occur too rapidly

Question 13

What are the 5 stages of repair to damage in the PNS?

Answer 13

1) Chromatolysis (Nissl bodies break up into fine granular masses) - 24-48h
2) Wallerian Degeneration (axon breaks into fragments; myelin sheath deteriorates; neurolemma remains) - 3-5 d
3) Macrophages phagocytize debris; synthesis of RNA and protein accelerates; Schwann cells multiply via mitosis, and may form regeneration tube across injured area
4) buds of regenerating axons begin to invade tube formed by Schwann cells, and grow toward distally located receptors and effectors
5) some sensory and motor connectiosn are re-established and some functions are restored. In time, Schwann cells forma new myelin sheath