7.2 lab - cells of nervous tissue Flashcards Preview

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Flashcards in 7.2 lab - cells of nervous tissue Deck (14)

how do many sensory neurons begin?

free nerve endings
-single, bare dendrites sitting in connective tissue or juxtaposed to a basal epithelial cell
-specialized sensory receptors include Meissner's and Pacinian's corpuscles


meissner's corpuscle

-tactile corpuscle (light touch sensor)
-encapsulated by connective tissue
-unmyelenated nerve endings
-horizontal lamellae
-located in dermis very close to epithelial layer
-most frequent in lips and fingertips
-in transverse section looks like a fingerprint


pactinian corpuscle

-lamellar corpuscle (pressure/vibration sensor)
-oval shape with connective tissue and modified schwann cells around fluid filled cavity with a single afferent unmyelenated nerve ending
-located in hypodermis (adipose layer) far from epithelial layer
-in transverse section looks like a sliced onion


this stain allow visualization not only of neuron soma but also dendrites and axons

silver stain


ventral horn of spinal column

larger butterfly wing in grey matter
ventral root proceeds out from it


dorsal horn of spinal column

smaller butterfly wing in grey matter
dorsal root feeds into it


why doesn't myelin stain very well?

it is composed of a phospholipid bilayer
lipids do not stain well usually


why does it make sense that neuronal cell bodies are so large?

consider the length of axon and dendrites they must support


spinal root

dorsal and ventral roots together = spinal root


major morphological difference between dorsal and ventral roots?

dorsal root ganglion


how to know if spinal section is in vertebra or between vertebrae

spinal roots = probably between?
no roots = probably within vertebra


what is a ganglion?

a collection of synapses (neuron soma and axons) outside the CNS (in the PNS)


what is difference between nissl & silver stain of nervous tissue?

nissl - soma mostly
silver - soma, axons, dendrites


why don't lipids usually stain?

they are usually dissolved in processing