13 ZOOL 409 Lab Week Tuesday

advertisement
ZOOL 409
TUESDAY Objectives:
Examine slides featuring nerve cells and
peripheral nerves.
1. Slide 88 -- Spinal cord smear. This is a smear
preparation, not a section (i.e., a bit of spinal
gray matter, not sliced but simply spread out
and pressed down on the slide). This may be
our best slide to see some of the shape of nerve
cells.


Lab Week 13
Tuesday and Thursday
Note texture of cytoplasm with Nissl bodies
(basophilic granules representing rough
endoplasmic reticulum ).
Note dendrites tapering away from cell
bodies.
o In slide boxes 1 and 8, look on each neuron for a pale
axon hillock and thin pale axon. This feature will not
be visible on most nerve cells (depending on how the
cells was flattened onto the slide) and may not be
apparent anywhere on a given slide.
4. Slide 10 -- Peripheral nerves.

This slide of "artery, vein, nerve" includes
relatively large nerves cut in cross section.

The conspicuous space between nerve sheath
and nerve fibers is an artifact from tissue
shrinkage.

The sheath is fibrous connective tissue
(mostly collagen and fibroblasts).

Nuclei that appear among the nerve fibers
belong to Schwann cells.
5. Slides 32, 62, 76 (and more) -- more nerves.

Peripheral nerves may be found on many
different slides. Look in connective tissue
(often near larger blood vessels) for a bundle
of fibers enclosed in a more-or-less distinct
sheath.
6. Slide 86 -- Nerve spread.

Note very numerous small nuclei belonging to
glial cells.


This slide displays a bit of nerve teased apart
and flattened on the slide, not sliced.
Some blood vessels may also be stretched
across the specimen.

Myelin and nodes of Ranvier should be
visible. Most of the thickness of each nerve
fiber is myelin; nodes are the neat gaps that
appear between one myelin segment and the
next.
2. Slides 89, 90, 91, 92 -- Spinal cord sections,
with various stains.


Nerve cell bodies appear prominently in the
ventral horn (the shorter, broader arm of the
"H" of gray matter).
Slide 92 includes nerve roots and dorsal root
ganglion.
3. Slides 91, 92, and more-- Ganglia.
 On slide 91 and 92, look for dorsal root ganglion
beside the spinal cord. Slide 91 is a Golgi stain for
Golgi bodies.
 Also see Auerbach's plexus, in the GI tract (e.g.,
slides 42, 43, 45, 44), between the circular and
longitudinal layers of smooth muscle.
7. Slide 87 -- Motor nerve endings.

This slide is a bit of striated muscle (not a
slice, but a spread) dissected at the site where a
motor axons synapse with muscle fibers.

Hunt for the long black nerve fibers, then try
to follow them to motor end plates.
Practical Quiz: see reverse side.
THURSDAY Objectives
Central Nervous Tissue.
See reverse side of this page.
 An autonomic ganglion can be found on slide 32
in Boxes 1,4,7,8 and on slide 71 in Boxes 2,3,4,7.
Last updated: 8 April 2013 / dgk
ZOOL 409
Tuesday and Thursday
Lab Week 13
TUESDAY Objectives: See reverse side.
ARTEFACT ALERT
THURSDAY Objectives:
Nervous tissue is difficult to fix well, and often
displays substantial shrinkage. This is manifested
as "halos", or clear empty spaces surrounding
various structures, particularly blood vessels and
nerve cell bodies.
Examine some regions of the
Central Nervous Tissue.
1. Slides 89, 90, 91, 92 -- Spinal cord sections,
with various stains.

Distinguish gray matter, forming an "H" or
"butterfly" shape surrounded by white matter.

Note cell bodies of motor neurons in the
ventral horn, the shorter, broader arm of the
"H" of gray matter:

Distinguish white matter, forming dorsal,
ventral, and lateral columns of axons travelling
up and down the cord.
2. Slides 96, 97, 98, 99, 100
Cerebral cortex.


On all of these slides, find nerve cell bodies
and note the associated volume of neuropil
(consisting of dendrites and axons, where most
synapses are located). Note many blood
vessels.
Slide 98 is a Golgi stain for nerve cells and
astrocytes.

Astrocytes are also demonstrated on Slide 99.

Slides 96 and 97 are silver stained, offering
some sense of neuropil structure.

Slide 100 is stained for microglia, probably
frog brain. (In blood vessels, red blood cells
have nuclei.)
3. Slides 94, 95 -- Cerebellar cortex.

On these slides, note the distinct layers, with
large cell bodies of Purkinje nerve cells in the
Purkinje cell layer between the granule cell
layer and the molecular layer.
Although such halos are artefacts, they are also a
fairly standard "feature" that helps call attention to
blood vessels and nerve cell bodies. The viewer
must bear in mind that surrounding neuropil should
be closely apposed to the haloed structures.
Practical Quiz
This quiz will simply confirm recognition of some
basic features on your slide-box slides.
□
□
□
□
□
□
□
□
On slide 88:
Indicate the nucleus of a neuron.
Indicate the nucleus of a glial cell.
On slide 91 or 92:
Indicate nerve cell body in ganglion.
On any appropriate slide:
Indicate nerve cell body in an autonomic
ganglion..
On slide 90 or 92:
Indicate white matter.
Indicate nerve cell body in ventral horn.
On slide 86:
Indicate a node of Ranvier.
On slide 62, 32, 34, 76, etc.:
Indicate a peripheral nerve.
On slide 93, 96, 97, 98, 99, 100:
Distinguish nerve cells from glia.
Indicate a blood vessel.
On slide 94 or 95:
Indicate a Purkinje cell.
Last updated: 4 April 2013 / dgk
Download