Histology SSN
October 26, 2004
NERVE
So Young Kim, sk2298
Missy Walker, maw2106
The Basics (fill in with presentation)
Nervous System Classifications (specific to this Histo lab)
Nervous System
Central NS
Spinal Cord
Cerebellum
Peripheral NS
Cerebral Cx
ANS
Somatic Enteric (GI)
(Ganglia) (Peripheral Nerve)
(Parasympathetic)
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(Sympathetic)
Histology SSN
October 26, 2004
Functions & Histological Features
CNS
Spinal Cord Cerebellum
Distinguishing *Butterfly
= gray matter
Feature
-- dorsal horn –
narrow, sensory
-- ventral horn –
wider, motor
*Purkinje
Cells
-
-
Functions
(general;
simplified)
White Matter
(axons)
*Pyramidal
Cells
eosinophilic
pear-flask
shaped;
UNIQUE
dendrites 
mlcr layer
f(n):
outflow of
cerebellum
Transmits
signals to &
from brain;
site of reflex
control
Motor
coordination
*exterior,
axons
traveling to
& from brain
- axons cut in
*most interior
layer – looks
diffuse, w/in
granular layer
cross section in
spinal cord
preparation
Gray Matter
(cell bodies)
Cerebral Cx
Higher
processing
Peripheral
Nerve
*Nerve
bundles
-- look for
- large, round
cells; prominent
nucleoli;
wreathed in
satellite cells
axons in crosssection (round,
clear/ white
bodies
(myelin) with
central “dot”)
Sympathetic
& Parasympathetic
Somatic
motor &
sensory
Note: slide
19&20 are of
sympathetic
ganglia
*interior
N/A
N/A
*exterior
N/A
N/A
(don’t confuse w/
outer, molecular
layer of gray
matter (see
below))
*butterfly
*molecular +
- processes
granular
from cell bodies layers
usually exit
gray matter in
plane of section
-- specialized
motor cortex;
distinctive
shape, scattered.
--very big clear
(euchromatic)
nucleus with
dark nucleolus
PNS
ANS
Ganglion
*Site of
neuronal cell
bodies
- molecular layer
= outermost,
pale staining,
mostly axons
& dendrites
- granular layer
= cellular,
basophilic
- Purkinje cells
separate the
two
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Histology SSN
October 26, 2004
Extraneuronal Cells
Function
Support
Myelin Production
Connective Tissue
Cells in CNS
Astroglia
Cells in PNS
Satellite Cells
- “star-shaped”
- structural support
extend processes to wrap
around capillaries  form
BBB
-
Oligodendrocytes
-produce & maintain myelin
Schwann Cells
- form myelin sheath that
sheath in CNS
None – NO Collagen
Neuronal Supporting Structures
Function
CNS
Meninges:
Supporting/Surrounding
Tissues:
Innermost Pia Mater – thin, direct contact
Middle
Outermost
with brain & SC
Arachnoid –“spider-web”;
sends delicate trabeculae to pia
(subarachnoid space is filled w/
CSF)
Dura Mater – “hard”; durable
outer covering
-
cuboidal cells, surround cell
bodies IN AUTONOMIC
GANGLIA
Do Not Make Myelin
insulates axons
Fibroblasts
PNS
For Peripheral Nerve
Bundles Only:
Endoneurium – Vascular,
arround individual nerve fibers
Perineurium – Arranges axons
into ‘fascicles’
Epineurium – binds ‘fascicles’
into ‘bundles’
Figure: Schematic of connective tissue layers in peripheral nerve
bundle.
Epineurium
binds fascicles 
bundles
Fascicle
Perineurium
binds nerves 
fascicles
Endoneurium
wraps individual
neurons
Peripheral Nerve Bundle
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Histology SSN
October 26, 2004
High-Yield Tips:

-
Peripheral Nerve vs. Smooth Muscle:
nerve tissue more compact and less eosinophilic
***nerve tissue wavy & bubbly – arises from myelin leaking out upon staining

-
Dendrites vs. Axons:
with Nissl staining, if see process that stains dark blue, dendrite, not axon. . . axons
contain no synthetic machinery and therefore do not stain w/ Nissl

-
Molecular Layer of Cerebellum vs. White Matter of Cerebellum (cerebellar
medulla)
Look for Purkinje cells. Purkinje cells are very distinct, and they demarcate the
border b/t molecular & granular layers of the cerebellum. The white matter of the
cerebellum resides underneath the basophilic granular layer.

-
Mnemonic: “Satellites are on the periphery of space.”
In other words, satellite cells are found in the peripheral nervous system.

Mnemonic: “Pyramidal cells are in the Cerebral Cortex.”
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Histology SSN
October 26, 2004
NERVE QUESTIONS
Questions 1-2 pertain to the structures at the pointers in Figures A and B.
1. Which of the following statements is correct regarding the cells at the pointers in Figures A
and B?
a. The cells are situated in white matter.
b. The cells are situated in a ganglion.
c. The cells are situated in the gray matter.
d. The cells are situated between the white and gray matter.
2. In Figure B the processes at the arrow are:
a. myelinated fibers.
b. axons.
c. collagen fibers.
d. dendrites
Question 3:
3. Which figure(s) demonstrates smooth muscle?
a. Figure A
b. Figure B
c. both Figures A and B
d. neither
Question 4:
4. The region at the pointer is required for: (choose all that apply)
a. protein synthesis.
b salutatory conduction.
c. insulation.
d. production of endoneurium.
Question 5:
5. All of the following characterize the organ depicted by the slide except:
a. Microglia
b. Myelinated axons
c. Fibroblasts
d. Oligodendrocytes
Question 6:
6. Which of the following is TRUE of the cell at the pointer?:
a. maintains stable microenvironment
b. resides in spinal cord.
c. is producing myelin.
d. transmits signals from molecular to granular layers.
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Histology SSN
October 26, 2004
NERVE ANSWERS
1. C. Cerebellum, Pointer A on Purkinje cell, Pointer B on Purkinje cell dendrite. This is
a Purkinje cell in the cerebellum, found at the junction between the molecular and
granular layers. The cell body lies in the granular layer. Its dendrites branch out in the
molecular layer.
2. D. The arrow points to the dendrites of the Purkinje cell in the molecular layer.
3. B. Figure A, peripheral nerve; Figure B, smooth musc. Peripheral nerve and smooth
muscle are hard to tell apart. Here are some distinctions:
-nerve tissue tends to be more compact, less eosinophilic, wavy and bubbly
because there are regions where myelin has leaked out.
-smooth muscle is more diffuse, more intense eosinophilic color.
4. B & C. Peripheral nerve, pointer on myelin sheath. The myelin sheath is layers of
lipid wrapping around the axon. It is required for saltatory conduction. It is also used for
insulation.
5. C. Figure depicts cerebral cortex. There are different support cells in the CNS and
PNS. This is a section from the CNS. There are fibroblasts in the PNS but not the CNS.
6. A. This is a satellite cell, found in autonomic ganglia. These PNS support cells do not
make myelin, while Schwann cells do. (Slide #83)
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