Neurosensory System

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Neurosensory System

• Histology Laboratory

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Spinal Cord. Transverse section. Weigert's stain.
Low power. White matter, i.e., nerve fibers in
tracts, (red arrows) lies peripherally. Central
gray matter (that is, where nerve cells are
located) stains lighter (yellow arrows) and is in
the form of an 'H'. The spinal cord is divided
into right and left halves by the anterior median
fissure (blue arrow) and the posterior median
septum (black arrow). The gray matter is divided
into large anterior or ventral (VH) and smaller
posterior or dorsal horns (DH). Large motor
neurons are present in the anterior horns.
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Spinal Cord. This image is a high magnification
of an anterior horn with some surrounding white
matter. The black arrows point to several of the
cell bodies of the large motor neurons (Golgi
type I).
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Spinal Cord. This image is a higher magnification
of the previous image illustrating a large motor
neuron (red arrow). Note the nucleus, which is
very characteristic of neurons large (relative
to surrounding nuclei), very little
heterochromatin, and a single, prominent
nucleolus. Only one process is visualized
projecting from the perikaryon. Since this
process contains Nissl, it would be identified as
a dendrite (yellow arrows). A number of smaller
nuclei are present (black arrows). The nuclei
belong to a group of cells known as Neuroglia.
They will be identified on a later slide
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Spinal Cord. This image is a higher magnification
of the previous image illustrating a large motor
neuron. Note the Nissl bodies in the perikaryon.
These bodies consists of rough endoplasmic
reticulum and free ribosomes. This material
extends into the dendrites but not axons.
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Cerebral Cortex. This image is a low
magnification of the cerebral cortex illustrating
multiple cell types (pyramidal, fusiform,
stellate, cells of Martinotti, and horizontal
cells of Cajal). At this magnification, it
difficult to determine any organized structure
with regard to cell types. The cells with the
black circle are enlarged on the next page.
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Cerebral Cortex. This image is a higher
magnification of the previous image. Two
pyramidal cells are illustrated (red arrows). The
apical dendrite from one of these cells is seen
projecting towards the top of the image (blue
arrow). The black arrows point to the lateral
dendrites. The axon which projects down is not
visualized.
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Cerebellar Cortex. This image is a low
magnification of the cerebellar cortex
illustrating the three cortical layers. The
Molecular layer is the most superficial and
contains interneurons including basket and
stellate cells. This layer is mainly a synaptic
zone, made up of branching dendrites of Purkinje
cells and the axons of granule cells (located in
the granule layer). Deep to the molecular layer
is the Purkinje layer consisting of a single
layer of Purkinje cells. Deep to the Purkinje
layer is the Granular layer containing a variety
of cell types including Golgi and granule cells).
Except for the Purkinje cells, you do not have
to identify specific cell types at this time.
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G
M
Cerebellar Cortex. This image is a higher
magnification of the previous image illustrating
three Purkinje cells (arrows). The molecular
layer (M) and the granular layer (G) are also
illustrated.
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Cerebellum. This image is a low magnification of
the cerebellum illustrating the boundaries of the
gray matter (red line) and the underlying white
matter (blue line). The area encircled in red is
enlarged on the next image.
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Purkinje Cell. This image is a high magnification
of the previous image illustrating a Purkinje
cell (red arrow). Note the apical dendrite
projecting up through the molecular layer (blue
arrows).
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Neuroglia. This image is a high magnification of
the gray matter of an anterior horn illustrating
the nuclei of neuroglia. Round nuclei belong to
Oligodendrocytes (red arrows). These cells are
closely associated with the cell processes of
neurons. Oligodendrocytes located in the white
matter are responsible for producing the myelin
sheath around the neuronal processes. The black
arrows are pointing to the nuclei of Astrocytes.
These cells have many cytoplasmic processes and
are connected to other cells and blood vessels.
They basically help maintain the structural
integrity of the CNS since there is no connective
tissue. Astrocytes in the gray matter are
referred to as Protoplasmic Astrocytes and those
in the white matter are referred to as Fibrous
Astrocytes.
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Neuroglia. This image is a high magnification of
the gray matter of an anterior horn illustrating
the nuclei of neuroglia. Oligodendrocytes are
indicated by the red arrows and a single
astrocyte by the green arrow. Microglia (black
arrows) represent a third type of neuroglia.
These cells are identified by their nuclei which
tend to be smaller than oligodendrocytes and
somewhat flattened and dark-staining. Microglia
are considered to be phagocytic.
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Astrocytes. This image is a special preparation
illustrating astrocytes (arrows) and their many
cell processes.
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Astrocytes. This image is a high magnification of
the previous image showing many astrocytic foot
processes attached around the circumference of a
blood vessel (black arrows).
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Ependymal Cells. This micrograph is of a
cross-section through the central canal of a
spinal cord. Ependymal cells for the epithelial
lining of this canal.
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Neuropil. This image is a high magnification of
the gray matter of spinal cord. The neuropil
(encircled in red) appears as a fine mottled area
between cell bodies of neurons.This consists of
the cell processes of cells (giving it a fibrous
appearance). The spaces between these cell
processes contains glycosaminoglycans (similar to
C.T. ground substance).
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Olfactory Epithelium. This is a low magnification
of olfactory epithelium from the roof of the
nasal cavity. A seromucous Bowman's gland is
illustrated in the lamina propria. Its duct opens
onto the surface. The secretions of these glands
provides a solvent for the olfactory stimulus and
washes the olfactory receptors to prevent
stagnation of the odor.
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Olfactory Epithelium. This is a higher
magnification of the olfactory zone illustrating
the pseudostratified columnar olfactory
epithelium. The dendrites of the olfactory cells
are indicated by the RED arrows.
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Olfactory Epithelium. Higher magnification of
olfactory epithelium. The dendrites of the
olfactory cells are indicated by the RED arrows.
The nuclei of these cells are about the midline
of the epithelium. The nuclei of the supporting
cells are closest to the lumen. The nuclei of the
basal cells are the ones closest to the basal
lamina.
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