SSB Histology Lab II
Muscle and Peripheral Nervous System
SSB Week 2
►►► NOTE: Slide numbers may differ from box to box. If you don't have the slide listed, ask your colleagues.
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INTRODUCTORY COMMENT on MUSCLE.
The structure of striated, skeletal muscle is best studied by
electron microscopy (i.e., through text-book pictures).
In Histology Lab, you should learn to recognize skeletal
muscle -- which means distinguishing it from other
fibrous, eosinophilic structures such as collagen and
smooth muscle.
Slide 34, Esophagus.
(EASY) Find smooth muscle.
(HARD?) This specimen may or may not include a few
striated muscle fibers. (The upper esophagus has striated
muscle, the lower esophagus does not.)
Slide 14, Striated Muscle.
(Note: This specimen displays isolated muscle samples,
stained to accentuate the striations. Be sure to appreciate
how plane-of-section affects the appearance of muscle
fibers.)
(EASY) In the longitudinal section, observe striations. In
the cross section, observe fiber diameter and myofibrillar
structure. Note position of nuclei.
Slide 10, Fibrocartilage.
(Note: This specimen includes tissues of the pubic
symphysis, with bone and cartilage as well as muscle.
(EASY) Find the skeletal muscle.
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PERIPHERAL NERVOUS TISSUE.
We really don't have any elegant preparations that show
special features of the peripheral nervous system. But
there are a few structures which may be interesting to
find.
Slide 55, artery, vein, nerve
(EASY) Find the nerve(s).
(EASY) Determine whether striated muscle is present.
Slide 15, Muscle, 3 types.
(EASY) Compare and contrast smooth muscle, cardiac
muscle, skeletal muscle. Questions: Can you see
individual cells? Can you really tell where the nuclei are
located?
(HARD?) IF striated muscle is present, look for a muscle
spindle (spindles are present on some but not all
specimens). Question: What makes muscle spindles
recognizable?
Slide 2, 3, 4, Skin
Slide 17, Motor Nerve Endings.
(Note: This is a "just-for-fun" preparation. The specimen
is a teased wholemount, not a section. A small bit of
muscle, at a site of innervation, was dissected free and
placed on the slide.)
(HARD?) Find some neuromuscular junctions. Hint:
Don't just look randomly -- sweep across the specimen at
low power and try to find black-stained nerve fibers.
Then follow these to their destination.
Slides 29, 30, Tongue
(EASY) Find the skeletal muscle (most of the bulk of the
specimen). Note fibers with different orientations (i.e.,
different planes of section).
(HARDER) Make sure you can distinguish muscle from
connective tissue.
(EASY?) Deep in the tongue, this specimen may also
include prominent nerves.
Slide 46, Anal Canal.
(HARD?) This specimen may include both smooth and
striated muscle. Determine what is present.
(EASY?) Find a nerve. Hint: Look deep. Question: Do
the axons in this nerve belong to sensory or motor nerve
cells? Explain why.
(HARD) Find a Meissner's corpuscle. Hint: Don't bother
looking unless the specimen on your slide shows thick
skin. Questions: How you recognize thick skin? Where
should you look for Meissner's corpuscles?
(EASY or IMPOSSIBLE) Find a Pacinian corpuscle. If
one of these structures is present, it will be obvious (up to
a millimeter in diameter, looking like an onion cut in
half). But most of our slides do not include any.
Slide 17, Sensory Nerve Endings.
(Note: This is a "just-for-fun" preparation. The specimen
is a teased wholemount, not a section. A small bit of
muscle and tendon, at a site of innervation, was dissected
free and placed on the slide.)
(HARD?) Find some sensory endings on the tendon.
Hint: Don't just look randomly -- sweep across the
specimen at low power and try to find black-stained nerve
fibers. Then follow these to their destination. Question:
How can you tell these are not motor endings?