responses to injury

Question 1

What are the neuronal changes in response to injury?In response to hypoxia/ischemia?

Answer 1

irreversible coagulative necrosis:

red dead neurons: eosinophilia, pyknosis, shrunken

Question 2

What specific neuronal changes accompany chronic CNS disorders, like Alzheimers, Parkinsons?

Answer 2

neuronal cytoplasmic alterations: neurofibrillary tangles-A, Lewy body-P, cytoplasmic storage-met. dz

reflecting abnormal cytoskeletal elements, by-product accumulation of disturbed metabolism.

Question 3

How does the nerve respond to axonal damage? 2 ways, and in what circumstances?

Answer 3

central chromatolysis- attempts to regenerate axon, and wallerian degeneration.

Can occur in sublethal injury

Question 4

How do astrocytes respond to injury? 2 ways

Answer 4

gliosis- fibrous astrocytosis: acutely hypertrophic astrocytes: gemistocytic
late reaction- glial scars

Alzheimers TII astrocytosis- protoplasmic astrocytosis: enlarged astrocyte nuclei and nucleoli, chromatin clearing. no glial scar.

Question 5

What are the results of oligodentrocyte injury?

Answer 5

demyelination, imparied impulse conduction along axons

papova virus: PML

Question 6

What are the results of ependymal injury?

Answer 6

necrosis-> ventricular lining gap and subependymal scar (glial nodule)

Question 7

Microglia respond to injury and form what in response to mild and severe injury?

Answer 7

mild- pleomorphic microglia
severe- tissue m@

early: activated and attack- neurophagia- to form pleomorphic microglia- capable of ingesting destroyed nerve cell fragments and myelin
acute severe destruction and chronic myelin degeneration forms m@

Question 8

What 3 types of edema can the brain result in?

Answer 8

vasogenic: extracellular fluid accumulation from BBB breakdown
cytotoxic: intracellular fluid accumulation within dead cells
interstitial: periventricular fluid accumulation in hydrocephalus

Question 9

What is the most common form of brain edema? What results in it?

Answer 9

Vasogenic, (from the loss of tight junctions in brain vessels, occurs in white matter and is mainly extracellular)

results from trauma, infection, tumor angiogenesis and hemorrhages (late infarcts).

Question 10

What causes cytotoxic edema?

Answer 10

cells injured by toxins or hypoxia causes Na/K pumps to fail

gray matter prominent and intracellular

Question 11

What are the gross results of edema on brain?

Answer 11

widened gyri, narrowed sulci, compression of lateral vesicles

Question 12

What is the most vulnerable to least vulnerable cells in brain in response to hypoxia?

Answer 12

neuron-> oligodendrocyte-> astrocyte-> microglia