Histology of Neural System

Question 1

What are the Lewy bodies?

Answer 1

Cytoplasmic inclusions of degenerating neurons of the substantia nigra, pars compacta, evident in Parkinson’s disease and in cortical and brain-stem neurons seen
in certain forms of dementia

Question 2

What are the Negri bodies?

Answer 2

Eosinophilic cytoplasmic inclusions seen in degenerating neurons in the hippocampus and cerebellar cortex in patients with rabies.

Question 3

What are the Neurofibrillary tangles?

Answer 3

In degenerative neuronal diseases of the CNS, a tau protein becomes excessively phosphorylated, which prevents crosslinking of microtubules. The affected microtubules form helical filaments and neurofibrillary tangles and senile plaques in the cell body and dendrites of neurons. Neurofibrillary tangles are prominent features of degenerating neurons in Alzheimer’s disease, amyotrophic lateral sclerosis,
and Down syndrome.

Question 4

What are the Nissl bodies?

Answer 4

Rough ER in neurons (synthesis of neurotransmitters)

Question 5

What are the mediators of anterograde and retrograde transport in neurons?

Answer 5

Anterograde transport is mediated by kinesin;

Retrograde transport is mediated by dynein

Question 6

Which viruses and toxins do occur because of retrograde transport?

Answer 6

• herpesvirus
• polio virus
• rabies
• tetanus toxin

Question 7

What muscle be intact for axon regeneration?

Answer 7

Endoneurium (superficial layer om myelin). Only in PNS nerves