Neuropath- Part 2

Mechanical separation of an axonal process from the proximal axon and neuron cell body.

The characteristic sequence of events following Wallerian degeneration. (3)

With Wallerian degeneration, within minutes of degeneration and necrosis of the distal axon, there is disruption of _________; within hours, there are ____________ and ____________.

With Wallerian degeneration, ______________ degeneration occurs for a short distance up the viable axonal process.

With Wallerian degeneration, ___________ occurs 2-10 days post injury.

With Wallerian degeneration, _____________ commences 2-3 weeks post injury.

Axonal regeneration in the PNS occurs by...

Axonal regeneration in the CNS is inhibited by ____________; it is also prevented by lack of a ____________.

Regeneration failure in the PNS occurs due to... (2)

Failure of reinnervation in the PNS is more likely when...

How does a neuroma develop?

Failure of a neuron to metabolically support the axonal process due to defective axonal transport.

The cause of neuraxonal dystrophy is thought to be _________.

Three ways that neuraxonal dystrophy can occur.

Disruption of slow antegrade transport causes neuraxonal dystrophy by causing swelling in the ___________ due to ____________; the __________ stays intact.

Disruption of fast antegrade transport causes neuraxonal dystrophy by causing a more ________________ without extreme _________.

Disruption of retrograde transport causes neuaxonal dystrophy by causing accumulation of __________ at the ___________ with ____________ of the fiber.

Disruption of retrograde transport is expressed as __________.

A non-specific reduction in dendritic complexity resulting from non-specific affects of disease or aging.

Non-specific neuronal reaction to injury in which there is a central loss of Nissl substance.

The initial change of central chromatolysis occurs within _________; this change is...

Central chromatolysis occurs during a cellular state of...

Accumulation of macromolecules resulting from states of increased/abnormal production or decreased elimination.

What are the different kinds of neuronal inclusions? (4)

Autofluorescent lipopigment resulting from normal wear and tear; poorly digestible products progressively accumulate within cells that occurs within increasing age.

Lipofuscin inclusions in a young animal suggests...

Defective lysosomal enzymes function associated with lysosomal storage disease results in _________________ and __________.

Inclusions of viral infection are formed by the accumulation of... (5)

Inclusions associated with cellular degeneration are called ___________; in the process of degeneration, ___________ may accumulate and be focally condensed by ____________.

Cytosegrasomes are seen with some _______________.

Eosinophilic cytoplasmic inclusions that resemble rabies viral inclusions that consist of collapsed lamella of the roughER.

What is the significance of incidental inclusions?

In order to confirm viral inclusions, also look for...

Loss of homeostatic capabilities resulting in cell death.

Due to the ________________, general cellular insults may selectively kill neurons.

The progression from degeneration to necrosis results in _____________ on HE stain.

Necrotic neurons are known as ___________.

Describe how necrosis causes increased eosinophilia on HE stain.

Nuclear changes associated with neuronal necrosis include... (4)

In response to tissue injury, microglial cells numbers are greatly complemented by _____________.

Describe the nuclei of inactive microglia.

Describe the nuclei of activated microglia?

Microglia that have been activated are filled with ___________, particularly _________; they often exhibit ___________ of the cytoplasm; these cells are called ____________.

Focal increase in microglial number in response to a selective insult.

Diffuse increase in microglial number secondary to a widespread selective insult or a non-selective insult.

The response to tissue injury is ____________ of astrocytes.

True fibrosis in response to tissue destructiononly occurs in association with __(2)__.

Activation of astrocytes is accompanied by increased expression of _____________ and an increase in ___________, resulting in ___________.

____________ can mark the presence of underlying tissue damage.

Focal increases in astrocytes that follow selective insult.

Increased number of astrocytes where the stimulus is widespread.

Injury to oligodendroglial and schwann cells results in swelling and fragmentation of ___________, followed by _________________; _____________ results in impaired ____________.

Primary demyelination occurs when...

What are possible etiologies of primary demyelination? (4)

Secondary demyelination occurs when...

In addition to axonal damage, damage to ____________ may also result in loss of metabolic support of the myelin-producing cells, leading to secondary demyelination.

What are the determinants of remyelination? (2)

The ____________ makes remyelination much less common in the CNS; additionally, it is more successful in the PNS because...

Increased brain tissue water content.

What is the significance of brain edema?

4 etiologies of brain edema.

Vascular leaking in the brain causes __________; it occurs because of loss of __________.

With time, brain edema fluid tends to accumulate in _____________, regardless of its origin.

Intracellular fluid accumulation causes ____________; fluid accumulates within ____________; selective insults, such as __(3)__ causes __(2)__.

Combination of vasogenic and cytotoxic edema is called the __________.

With the edema cycle, primary endothelial injury leads to ________ edema and decreased ___________; this leads to __________ and _________ edema.

With the edema cycle, primary astrocytic insult leads to ________ edema and _____________; this causes ___________ and low ________; loss of __________ results in ___________ injury and __________ edema.

Increased CSF pressure causes _____________; can be secondary to __(2)__.

With transependymal edema, CSF is pushed into the ___________, separating ___________ from their source of metabolic support and causing loss of __________.

The _____________  is a salient feature of hydrocephalus due to ____________.

Edema caused by toxic insult to oligodendrocytes, causing splitting of myelin lemella.

Intramyelinic edema may be caused by __(2)__ and results in __________.

Histologic changes associated with brain edema.

Polymicrocavitation on histopath reflects...

Fluid accumulates within astrocyte processes with ___________.

Fluid accumulates b/w myelin lamellae with ___________.

Fluid accumulates within b/w cells with __________.

What are sequelae to brain volume expansion and increased intracranial pressure? (5)

Flattening of gyri is sequela of increased intracranial pressure with ____________; asymmertry of the brain occurs with __________.

With ischemic brain necrosis, swelling compresses __________; if severe and prolonged brain swelling is reduced therapeutically, ______________ can cause a severe ___________ edema.

Herniation is often secondary to initiation of _________.

What are areas of te brain where herniation commonly occurs with edema? (3)

When the occipital cortex herniates and slips beneath the tentorium cerebelli, the herniateed portion compressed the ___________, which is displaced __________.

When the cerebellar vermis herniates through the foramen magna, the __________ is compressed as a result.

What is the significance of herniation in the brain?

Pathology consisting of enlarged ventricles and a very thin cortex.

With brain herniation, compression is sufficient to occlude ____________ but not ___________; therefore, tissue is ____________, called ___________.

Brainstem compression by herniated cerebellum causes sudden death through...

Demyelination is associated with _______________ edema.

Demyelination due to persistent white matter edema underlies the ____________ that is associate with ____________ edema.

Death of a specific cell type.

Death of all components of a tissue.

With pannecrosis, __(2)__ may survive, resulting in __________.

Determinants of selective vs pannecrosis. (3)

Cells that are #1 susceptibilty to necrosis. (2)

Cells that are #2 susceptibilty to necrosis. (1)

Cells that are #3 susceptibilty to necrosis. (2)

Mild inults are more likely to induce _________, whereas qualitatively similar severe insult may cause __________.

Distribution or extent of necrosis varies depending on... (3)

Heat-shock proteins mediate cell recovery by... (5)

Neurons with __________ of HSP are most at risk for diverse insults.

Glutamate excitotoxicity leads to...

___________ is the primary excitatory neurotransmitter in the brain.

The excitation signal in an excitable brain cell is terminated  by....

With glutamate toxicity, excessive glutamate release occurs secondary to ____________, causing degeneration and necrosis of __________; ___________ can further predispose neurons to injury since glutamate uptake by astrocytes is _____________.

Mechanism of excitotoxicity: NMDA receptors become refractory to the modulatory effects of ________ with prolonged ____________, resulting in excess ________ entry into the post-synaptic neuron; the high intracellular _______ activates enzymes that destroy the ___________ of the cell.

Glutamate toxicity increases the _____________.

Diseases where excitotoxicity has been implicated. (5)

Resolution of pannecrosis consists of _________ mediating the clean-up, becoming laden with ___________, and ultimately forming a ___________. Astrocytes form a _________; the cavity becomes filled with _________.