Pathology Flashcards
cellular responses to injury
rapid necrosis
slow atrophy
what is Nissl substance
large granular body in neurons - RER
when is a red neuron found
in acute neuronal injury
how does a red neuron arise
hypoxia/ischaemia
when are red neurons visible
12-48 hours after irreversible insult to cell
why is a red neuron called what it is
intensely red cytoplasm
list other neuronal responses to injury
axonal
chronic degeneration
sub cellular alterations - inclusions
What is Wallerian degeneration
axonal response to injury where there is degeneration of myelin and axon distal to site of injury
give an example of subcellular alterations / inclusions
neurofibrillary tangles in Alzheimers
What is the main cell involved in repair and scar formation
astrocytes
what is gliosis
astrocyte damage
what are the early stages of gliosis
hyperplasia and hypertrophy of astrocytes
what is the most important histopathological indicator of CNS injury regardless of cause
gliosis
what does damage to oligodendrocytes result in
demyelination
what are oligodendrocytes sensitive to
hypoxia
Ependymal cells have a limited response to injury, true or false
true
M2 microglia are anti/pro inflammatory
ANTI inflammatory
causes of nervous system injury
hypoxia trauma toxins metabolic abnormalities nutritional deficiencies infections genetics ageing
Why is excitotoxicity important
important mediator of neuronal injury
what is excitotoxicity
hypoxia leads to reduced ATP production and so reduced energy followed by neuronal depolarisation
glial cells fail to reuptake glutamate resulting in a glutamate storm
this excites post synaptic GluR resulting in rapid Ca2+ accumulation in post synaptic neuron
what are the 3 outcomes of Ca2+ accumulation in excitotoxicity
protease activation
mitochondria dysfunction
oxidative stress
what is cytotoxic oedema
accumulation of Na and Cl in the CELL resulting in a shift of water to the cell also
causes of cytotoxic oedema
alcohol intoxication
Reye’s
hypothermia
what is ionic/osmotic oedema
movement of Na, Cl and water into interstitium
causes of ionic oedema
SIADH
increased water uptake
what is vasogenic oedema
disruption of BBB resulting in larger molecules like albumin bringing in water
causes of vasogenic oedema
trauma tumours inflammation infection encephalopathy
what is haemorrhagic conversion
BBB is majorly disrupted that RBCs enter
in global hypoxic ischaemic damage, what does the MAP fall below
50mmHg
define stroke
sudden disturbance of cerebral function of vascular origin that causes symptoms lasting more than 24 hours
what can cause cerebral infarction
thrombus from atherosclerosis - commonly MCA
embolus - from internal carotid artery or from the heart