The name is absent

Because of the large concentrations of ribosomes, neuronal cell bodies stain
heavily with basic dyes such as thionin and cresyl violet, which are routine stains
for neuropathological studies. In many of the larger neurons, thionin and cresyl
violet stains reveal clumps of heavily stained material, termed Nissl bodies. Nissl
bodies represent the stacks of rough endoplasmic reticulum visible at the
electron microscopic level.

The distribution of Nissl substance is an indication of the protein synthetic activity
of the neuron. When conditions lead to decreases in protein synthesis, there are
decreases in Nissl staining. For example, when neurons are axotomized, they
often exhibit a response termed chromatolysis, which is characterized by a
dispersal of Nissl substance. During the time that the Nissl substance is
dispersed, protein synthesis is decreased. Neuronal cell bodies also contain a
prominent Golgi apparatus, like other secretory cells. As in other cell types, an
important function of the Golgi apparatus of neurons is terminal glycosylation of
proteins synthesized in the rough endoplasmic reticulum.

The axon is the output projection that branches into axonal collaterals that reach
distant dendrites of target neurons. Study of CA3 -> CA1 axo-dendritic synapses
shows that the synapses are formed at 2.7 μm intervals along the axons, the
axonal shafts are 1.4 ± 1.2 μm long and the varicosities have oblong form and
length - 1.1 ± 0.7 μm (Shepherd & Harris, 1998). It is also possible axo-axonal
electric synapses known as gap junctions to account for ultrafast (200Hz)
signalling between neurons. Axons contain microtubules, usually with closer
spacing than in dendrites.

11

<<   8   9   10   11   12   13   14   >>

More intriguing information