7.2 lab - cells of nervous tissue Flashcards
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)
- mechanoreceptor
- 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)
- mechanoreceptor
- 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
