Week 6 Lesson 41b: Responses of Nervous tissue to injury

What are the clinical signs of a nervous disease?

1. Altered Mental State

2. Involuntary movements

3. Abnormal Posture and gate

4. Paralysis

5. Altered sensations

What are important concepts to understand about how the CNS responds to injury?

• Neurons have only small energy stores

• Neuronal regeneration

• Transection of nerves

• Healing in the CNS

• Cranial cavity is filled by the brain, meninges, and fluids

• BBB

• CNS is able to resist infection and injury

Which cells of the CNS are most sensitive to injury?

Neurons

What neuron reacts to injury caused by excitotoxicity and oxidative damage?

Acidophilic neuronal necrosis

What neuron reaction to injury is caused by viral infections such as rabies?

Intraneuronal inclusions

What type of neuron reaction to injury is caused by spongiform encephalopathy?

Empty cytoplasmic vascuoles

What are some examples of spongiform encephalopathy?

Chronic wasting disease or mad cow disease

What type of neuron reaction to injury is caused by neuronal injury?

Chromatolysis

What type of neuron reaction to injury is caused by programmed cell death?

Apoptosis

What type of neuron reaction to injury is caused by necrosis and neuronophagia

Neuronal loss

What type of neuron reaction to injury is caused by Wallerian degeneration, trauma, or ischemia?

Axonal and dendritic changes

What happens to the neuronal cell body after axonal injury, degenerative conditions, viral infection, or inherited conditions?

Central chromatolysis

What does the saying red dead mean for the neuronal cell body changes?

Ischemic cell change

What happens to the neuronal cell body in lysosomal storage diseases?

Enlargement of the cell body

Accumulation of what pigment happens in aging of neuronal cell body?

Lipofuscin

Accumulation of what substance occurs in the neuronal cell body during certain neuronal degenerative disorders?

Neurofilaments

What are the two types of inclusion bodies form during certain viral infections?

intra-neuronal inclusion body

intra-cytoplasmic inclusion body

How is the cytoplasm if neuronal cell bodies are effected in spongiform encephalopathies?

It creates cytoplasmic vaculoation

Describe the sequence of Wallerian degeneration in the PNS?

1. Normal

2. Dengeneration and fragmentation of axon and myelin, distance from cell body is important

3. Removal of axonal and myelin debris by phagocytosis

4. Regeneration of the axon if the endoneurium is intact

5. Remyelinization by Schwann Cells

Answer the question above

Glutamate-mediated excitotoxcity

What glial cell responds to injury by demyelination (1, 2)?

Oligodendrocytes

What Glial cell responds to injury by astocytosis, astrogliosis?

Astocytes

What glial cells respond to injury by micogliosis and neuronophagia?

Micoglia

Why type of cells respond to cell injury by viral cytolysis, ependymitis or traumatic loss, atrophy, with loss of cilia?

Ependymal cells

What type of cells respond to cell injury by choroid plexitis?

Choroid Plexus cells

What cells respond to cell injury by meningitis, osseous metaplasia?

Meninges

What blood vessels respond to injury via infection and inflammation?

Blood Brain Barrier (BBB)

What blood vessels respond to injury via swelling, degeneration, proliferation, and hypertrophy?

Endothelial cells (BVs)

Which microscopic change in neurons is due to acute hypoxic-ischemic injury?

Ischemic cell change (red neurons)

Answer the question above.

Wallerian degeneration

What plays an important regulatory role in homeostasis of exchange of water and electrolytes between the blood and CNS?

Blood brain barrier

What is excess fluid accumulation in the CNS parenchyma?

Edema

What are the three different types of edema?

1. Vasogenic

2. Cytotoxic

3. Interstitial

What type of edema is caused due to vascular injury with the breakdown of the BBB and causes extracellular accumulation of fluid?

Vasogenic edema

What type of edema is caused by altered cellular metabolism and causes intracellular accumulation of fluid?

Cytoxic edema

What are the three main effects of brain edema?

1. Focal or global CNS swelling → usually due to abscesses, tumors, or hemorrhages

2. Swelling causes an increase in intracranial or intraspinal pressure with life-threatening secondary complications

3. Lesion → Hemorrhages and herniation

What type of lesion is caused due to stretching and necrosis of blood vessels in the brainstem and cerebellum?

Hemorrhages

What type of lesion can cause hemorrhages in the brainstem or cerebellum?

Herniation

Herniation of what part of the brain causes an increasing pressure in focal areas, disrupting blood supply, leading to hemorrhages and ischemic necrosis, which is usually fatal?

Cerebral cortex

Answer the question above.

Vasogenic edema