Nervous Tissue Damage and Disorders (Nursing)

00:00 So now let's talk a little bit about what happens when we damage nervous tissue and if and how it can be repaired.

00:09 Although the nervous system is able to exhibit plasticity which involves the ability to change based on experience such as learning things over time, neurons also have a limited ability to regenerate themselves which involves replicating or repairing.

00:31 In the central nervous system which is the brain and the spinal chord, there is very little to no repair.

00:40 This is due to several different factors. First, their inhibitory influences from the neuroglial cells such as the oligodendrocytes found wrapped around these neurons.

00:55 Secondly, after fetal development, there's an absence of the growth-stimulating cues that we find during development.

01:05 Lastly, there's a rapid formation of glial scar tissue in the central nervous system that leaves little room for repair to take place.

01:16 This is different in the peripheral nervous system.

01:21 In the peripheral nervous system, repair is possible as long as the cell body is intact, the Schwann cells are still functional, and scar tissue has not formed too quickly.

01:35 The steps that are involved in the repair process of the peripheral nervous system include chromatolysis.

01:45 In this step, the Nissl bodies which are found inside of the cell body of the neuron are going to start to degenerate and migrate away from the cell body.

01:58 It's called chromatolysis because the Nissl bodies have a very distinct color to them.

02:05 In the second step of the repair process in the peripheral nervous system, we have Wallerian degeneration.

02:13 During this step, the part of the neuron that is distal to the injury begins to degenerate.

02:21 Finally, we have the formation of the regeneration tube.

02:28 This begins the repair process of the part of the neuron that is distal to the neuron injury.

02:36 We will conclude this lecture by talking about the different types of disorders that affect the nervous system.

02:45 The first of those disorder that we will discuss is multiple sclerosis.

02:50 Multiple sclerosis affects the myelin sheath of the central nervous system that leads to demyelination and glial scar formation which can slow or disrupt nerve signal conduction.

03:02 This then slows down the speed of conduction to the skeletal muscles.

03:08 A second disorder in the nervous system is epilepsy, characterized by recurrent seizures.

03:15 These seizures are the result of sudden, excessive electrical activity in the brain.

03:20 Interestingly about epilepsy is it usually does not hurt or bother intelligence.

03:28 A third type of disorder found in the nervous system is excitotoxicity.

03:36 In this, you have a high level of glutamate that's found in the interstitial fluid which leads to a prolonged activation of the neuron.

03:48 In this case, the neuron is never getting any rest and is pretty much activated to death.

03:54 This usually happens in situations where you have oxygen deprivation such as during a stroke.

04:03 And then finally, we have depression in which there are many different types.

04:09 Unlike many of these other nervous system disorders have or the exact cause of depression is not yet known and is still being studied.