Neurodegeneration

Question 1

what are the 4 mechanisms of neurological disorders?

Answer 1

Autophagy
oxidative stress
apoptosis
necrosis

Question 2

what is autophagy

Answer 2

the normal housekeepings of a cell to maintain function of neurons

Question 3

what is another function of autophagy?

Answer 3

it acts to recycle proteins, lipids and nucleic acids through lysosomes

Question 4

what are lysosomes?

Answer 4

Membrane bound organelles containing an array of hydrolytic enzymes

Question 5

function of hydrolytic enzymes

Answer 5

they deal with a range of substrates transported into the lysosomes via invagination or across the membrane

Question 6

what are the 4 processes of autophagy?

Answer 6

eliminating waste
protect against variations of nutrient availabilities
promoting cellular remodelling
protection against invading pathogens.

Question 7

how do toxic substrates accumulate in autophagy?

Answer 7

when these housekeeping functions in the neurons become disordered or unbalanced.

Question 8

How does oxidative stress arise?

Answer 8

arises from reactive oxygen species (ROS) which are hydrogen peroxide, hydroxyl and superoxide.

Question 9

what can oxidative stress lead to?

Answer 9

oxidative damage within nerve cells.

Question 10

What does ROS stand for?

Answer 10

Reactive Oxygen Species

Question 11

What are ROS products of?

Answer 11

they are products of mitochondrial energy production in very low levels.

Question 12

What happens if the mitochondria develop any defects?

Answer 12

then the production of ROS will increase which can lead to some denaturation of some proteins.

Question 13

How then can a toxic substrate form as a result of oxidative stress?

Answer 13

after the denaturation of a protein some may be repaired, if the repair misfolds then a toxic element may be produced which can collect within the cell.

Question 14

what effect does the production of toxic elements collecting within the cell have on the neuron?

Answer 14

causes the neuron to misfunction or more likely be destroyed.

Question 15

What is Apoptosis?

Answer 15

the cellular mechanism for orderly destruction.

Question 16

describe stage 1 of Apoptosis

Answer 16

It is triggered within the cell which then starts of a proteolytic cascade of reactions

Question 17

what is the result of this cascade of reactions?

Answer 17

the cell contents dismantles leading to cell shrinkage which causes the cell to become a target for phagocytosis by macrophage.

Question 18

What does this mean for the person?

Answer 18

it causes a huge loss of neuron is the nervous system that wont be replaced.

Question 19

what is neuronal plasticity?

Answer 19

the rewiring of remaining neurons

Question 20

what role does neuronal plasticity play in apoptosis?

Answer 20

neuronal plasticity compensates for the loss of neurons in the nervous system to a great extent.

Question 21

What is Necrosis?

Answer 21

it is a process of cell death involving overt damage to cells initiating an inflammatory response and a clean up by the immune system.

Question 22

what contribution to neurodegeneration does necrosis have?

Answer 22

contributes to the loss of neurons and the progression of disease pathology

Question 23

What damage is Necrosis associated with?

Answer 23

cellular injury
inflammation
damage to neighbouring cells

Question 24

name 2 conditions that can cause necrosis to occur

Answer 24

1. Stroke
2. ischemic Injury

Question 25

Explain how stroke and ischemic injury causes necrosis to occur.

Answer 25

insufficient blood supply to the brain which deprives neurons of oxygen and nutrients, leading to necrotic cell death

Question 26

what else is associated with neurodegenerative diseases?

Answer 26

impairments in:
- protein degradation
- folding and unfolding
- axonal transport
- mitochondrial function