NP1E Flashcards
Where are neuron cell bodies located?
Grey matter
When does the grey color emerge?
it emerges after formalin fixation
Where is grey matter located in the forebrain?
grey matter is on the outer surface (cortex) or in discrete areas within the tissue known as nuclei
Axons coming to or leaving grey matter are bundled to form __________ tracts
White matter
Why are the tracts white?
Because of the low density of blood vessels and the high fat content of myelin
List what is seen in grey matter, cerebral cortex
Neurons
Astrocytes
Oligodendrocytes
- the cytoplasm is visible, with blue Nissl substance
- there is significant variation in cell size that is a function of axon length
- nuclei are large, round with a prominent nucleolus
- dendrites and axons can be appreciated when sections are made very thick, and silver stains are used to define neuronal structure
Neurons
- the cytoplasm and projections are not visible (lost in the neuropil)
- Nuclei are the largest of the glia and tend to be round with a dispersed chromatin pattern
Astrocytes
- cannot be distinguished from resting microglia with H&E stained sections
- are located in the GM, although the density is much higher in the WM
- the cytoplasm and processes are not visible (lost in the neuropil)
- Nuclei are small, round and hyper chromatic . Nuclei will sometimes be located adjacent to neuronal cell bodies, this location being more unique to oligodendroglia compared to microglia
Oligodrendrocytes
What is the predominant cell type in WM?
Oligodrendroglia
White matter, cerebral cortex
Oligodendroglia
microglia
astrocytes
Axons become visible if they have myelin sheath
This organization is unique in that it has a molecular layer consisting primarily of dendrites of large Purkinje cell neurons as they receive axons from other regions. Cell nuclei in the molecular layer are those of oligodendrocytes, microglia and astrocytes. Beneath the Purkinje cell layer are very small densely packed granular cell neurons (forming the internal granular cell layer). At the core is white matter, as with the cerebral cortex
Cerebellar cortex
Grey Matter is organized into:
- ventral horn
- lateral horn
- dorsal horn
ventral horn is home to:
motor neuron cell bodies
lateral horn is home to:
neuron cell bodies of the sympathetic nervous system
dorsal horn is home to:
neurons that receive somatosensory (denoting a sensation) information from the body
__________ tracts in the ventral and lateral aspects (termed funiculi) are descending fron the forebrain or more rostral aspects of the spinal cord. _________ tracts in the dorsal and lateral funiculi are ascending
White Matter
A ___________ nerve root emerges from motor neurons of the ventral horn
ventral spinal
the dorsal horn receives axons from the neuron cell bodies in the ___________ ganglia
dorsal root
Term used for groups of neuron cell bodies in the periphery
Ganglia
Who are responsible for myelinating the roots, highlighting the distinctive appearance of central and peripheral myelin sheaths?
Schwann cells
Sympathetic neurons
Parasympathetic neurons
Autonomic system
connective tissue separating axons and their Schwann cells is called ___________
endoneurium
a surgeon manipulates a nerve by grabbing the _________ and the fat within to prevent axons from being crushed
epineurium
You are performing a gross post mortem examination, and you see pathological changes localized to grey matter. How do you interpret this change?
The disease is targeting neurons
Astrocytes and Oligodendricytes not visible
You are performing a gross post mortem examination, and you see pathological changes localized to white matter. How do you interpret this change?
the disease is targeting oligodendrocytes
