Medical School Histology Basics
Muscle
VIBS 289 lab
Larry Johnson
Texas A&M University
MUSCLE Function and Features
Function:
• Generation of contractile force
• Locomotion of multicellular animals, beating of
their hearts, and movement of their internal
organs depends on muscles of different types.
Distinguishing features:
• High concentration of contractile proteins actin
and myosin arranged either diffusely in the
cytoplasm (smooth muscle) or in regular
repeating units called sarcomeres (striated
muscles, e.g., cardiac and skeletal muscles)
• All three muscle types comes from mesoderm
TYPES OF MUSCLE
•
SKELETAL MUSCLE
– VOLUNTARY, LARGE AND MULTINUCLEATED CELLS,
STRIATED
•
CARDIAC MUSCLE
– INVOLUNTARY, MONONUCLEATED AND BRANCHED
CELLS, STRIATED
•
SMOOTH MUSCLE
– INVOLUNTARY, MONONUCLEATED, NON-STRIATED
Smooth muscle
no striations
Ureter (Slide 262 smooth muscle)
Connective
tissue
Transitional
epithelium
Connective
tissue
Smooth muscle fibers are long, spindle-shaped
cells shown here as bundles of cells
Slide 19678
Smooth muscle and psudostratified columnar
epithelium in ductus deferens
(toluidine blue)
Smooth
muscle cells
Slide 32409: Rat intestine
(toluidine blue)
Central lacteal
epithelium
Gut lumen
Muscularis externa
smooth muscle,
Slide 32409: Rat intestine (toluidine blue)
vein
epithelium
lacteal
Auerbach’s plexus
Meissner’s
plexus
Smooth
muscle,
muscularis externa,
muscularis mucosa,
Duodenum (Slide 152) Smooth muscle
longitudinal profiles
Transverse profiles
of smooth muscle cells
sarcoplasm in these
cells have no regular
cross striations
longitudinal and transverse profiles of
smooth muscle cells
243 PAS staining of smooth muscle cell
basement membrane in the stomach
Smooth muscle cell nuclei
Smooth muscle; EM 9 of smooth
muscle cells, note organelles
1. Nucleus of smooth muscle cell
2. Secondary lysosome
3. Mitochondrion
10 f
EM 10f: Arteriolar wall;
30,000x
1. Apical caveolae
2. Collagen
3. Dense bodies
4. Elastic fiber
5. Endothelial cell
6. Nuclear pore
7. RER
Smooth muscle; EM 10e of
smooth muscle cell. Note
nerve attachment
1. Smooth muscle cell
2. Collagen
3. Nerve ending
4. Mitochondrion
Individual cells
Slide 136: Tongue, monkey
Connective tissue of the
perimysium
capillaries
nerve
Skeletal
muscle cells
Perimysium
Slide HISTO007: Skeletal muscle – nerve and
motor end plates
Motor end plates in skeletal muscle
One nerve innervates several muscle cells
Histo 07
Skeletal
muscle cells
Slide HISTO007:
Skeletal muscle
motor end plates
Slide 136
SKELETAL MUSCLE
Slide 136: Tongue, monkey
Anisotropic to polarized light =“A” band = dark band
Isotropic to polarized light = “I” band = light band
A band
I band
A band
I band
Slide 136: Tongue, monkey
Skeletal muscle nuclei
Fasciculi
Endomysium
Muscle
cells
skeletal muscle nuclei,
Connective
tissue of
perimysium
striations
Slide 136: Tongue, monkey
Capillaries in skeletal muscle
endomysium
211
211 -001
Skeletal muscle
Striations = A&I bands
skeletal muscle
cell nuclei,
Cross striations in skeletal muscle cells (Slide 211-001)
211
Skeletal muscle
cells
A band
Z disc
I band
EM 10; skeletal muscle;
30,000x
1. Mitochondria
2. Sarcoplasmic reticulum
3. Terminal cisternae
137
Esophagus – skeletal and
smooth muscle
Connective tissue
nerve
Contracted skeletal muscle cells
have small I bands
EM 10a: Endothelial cells
lining capillary with
pericyte in the vessel wall;
20,000x
1. Lumen
2. Endothelial cell
3. Tight junction
Nerve – muscle interface
at the motor end plates
Muscle spindles
stretch receptors
Muscle fibers inside a
connective tissue
capsule
Slide HISTO007 skeletal muscle cells
Nerve – muscle interface at the motor end plates
Note the motor end plates in several skeletal muscle cells
Muscle spindle #19753
19753 Muscle spindles
Intrafusal
fibers inside the capsule
136 Tongue Muscle spindle
Muscle spindles
capillaries
Intrafusal
fibers inside the capsule
nerve
fibroblasts
Skeletal muscle cells
Cardiac muscle cells
Intercalated disc = cell attachments
211
225
EM 10b
225
Intercalated disc in cardiac cells of the Heart,
epicardium
A band
I band
Slide 226
Cardiac muscle cells are striated
Cardiac muscle cells
are branched
Cardiac cells are separated at the intercalated discs revealing the shape of individual
cells, that the cells are branched, and the nuclei are in the center of cells.
Slide 226
Cardiac muscle cells are striated
Cardiac muscle cells
Cardiac cells can accumulate a high density of lipofuscin granules
resulting from incomplete lysosomal digestion within the cell
Heart
Internodal connections
Histo0 23
heart muscle
Cardiac muscle cells
Purkinje fibers
EM 10b cardiac muscle cells
Intercalated discs
EM 10b
Gap junctions
Intercalated discs
CARDIAC MUSCLE –
Skeletal muscle – triad
located at A-I junction
Diad located at Z disc
Diad = (T tubule +
one end of SER)
TRIAD = (T TUBULE +
TWO ENDS OF SER)
EM 10
EM 10b
Skeletal muscle cell
triad
Cardiac muscle cell
diad
Test Questions on Muscle
Which is (are) true about striated muscle?
a. The “A” band = dark band = anisotropic to polarized light
b. The “I” band = light band = isotropic to polarized light
c. The endomysium is delicate connective tissue around individual myofibrils
d. a & b
e. a, b, & c
Which types of muscle have nuclei in the center of its cells and are
involuntary:
a. Smooth muscle
b. Cardiac muscle
c. Skeletal muscle
d. a and b
e. a, b and c
Which is/are related to stimulation of muscle contraction:
a. Motor end plate
b. Gap junctions
c. Purkinje fibers
d. a and b
e. a, b and c
In summary
Many illustrations in these VIBS Histology YouTube videos were modified
from the following books and sources: Many thanks to original sources!
•
•
Bruce Alberts, et al. 1983. Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY.
Bruce Alberts, et al. 1994. Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY.
•
William J. Banks, 1981. Applied Veterinary Histology. Williams and Wilkins, Los Angeles, CA.
•
Hans Elias, et al. 1978. Histology and Human Microanatomy. John Wiley and Sons, New York, NY.
•
•
Don W. Fawcett. 1986. Bloom and Fawcett. A textbook of histology. W. B. Saunders Company, Philadelphia, PA.
Don W. Fawcett. 1994. Bloom and Fawcett. A textbook of histology. Chapman and Hall, New York, NY.
•
Arthur W. Ham and David H. Cormack. 1979. Histology. J. S. Lippincott Company, Philadelphia, PA.
•
•
Luis C. Junqueira, et al. 1983. Basic Histology. Lange Medical Publications, Los Altos, CA.
L. Carlos Junqueira, et al. 1995. Basic Histology. Appleton and Lange, Norwalk, CT.
•
L.L. Langley, et al. 1974. Dynamic Anatomy and Physiology. McGraw-Hill Book Company, New York, NY.
•
W.W. Tuttle and Byron A. Schottelius. 1969. Textbook of Physiology. The C. V. Mosby Company, St. Louis, MO.
•
•
Leon Weiss. 1977. Histology Cell and Tissue Biology. Elsevier Biomedical, New York, NY.
Leon Weiss and Roy O. Greep. 1977. Histology. McGraw-Hill Book Company, New York, NY.
•
•
•
Nature (http://www.nature.com), Vol. 414:88,2001.
Arthur C. Guyton,1971.Textbook of Medical Physiology W.B. Saunders company, Philadelphia, PA
WW Tuttle and BA Schottelius 1969 Textbook of Physiology C.V. Mosby Co.
•
A.L. Mescher 2013 Junqueira’s Basis Histology text and atlas, 13th ed. McGraw
Big Bend National Park, TX
The end of