Medical School Histology Basics Muscle

VIBS 289 lab

Larry Johnson Texas A&M University

MUSCLE Function and FeaturesFunction:•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 muscleno striations

Ureter (Slide 262 smooth muscle)

Smooth muscle fibers are long, spindle-shaped cells shown here as bundles of cells

Connective tissue

Transitional epithelium

Connective tissue

Smooth muscle and psudostratified columnar epithelium in ductus deferens

(toluidine blue)

Smooth muscle cells

Slide 19678

Muscularis externasmooth muscle,

Slide 32409: Rat intestine (toluidine blue)Central lacteal epithelium

Gut lumen

Smooth muscle, muscularis externa, muscularis mucosa,

Slide 32409: Rat intestine (toluidine blue)

Meissner’s plexus

Auerbach’s plexus

vein

lacteal

epithelium

longitudinal and transverse profiles of smooth muscle cells

Duodenum (Slide 152) Smooth muscle

longitudinal profiles

Transverse profiles of smooth muscle cells

sarcoplasm in these cells have no regular cross striations

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

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

10 f

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

nerve

Skeletal muscle cells

capillaries

Connective tissue of the

Perimysium

perimysium

Histo 07

Slide HISTO007: Skeletal muscle – nerve and motor end plates

Motor end plates in skeletal muscleOne nerve innervates several muscle cells

Slide HISTO007: Skeletal muscle motor end plates

Skeletal muscle cells

SKELETAL MUSCLESlide 136: Tongue, monkey

Slide 136

A band I band

A band I band

Anisotropic to polarized light =“A” band = dark band Isotropic to polarized light = “I” band = light band

Slide 136: Tongue, monkeySkeletal muscle nuclei Fasciculi Endomysium

Muscle cells

striations

Connectivetissue of

skeletal muscle nuclei,

perimysium

Capillaries in skeletal muscleendomysium

Slide 136: Tongue, monkey

211 -001 Skeletal muscle211

skeletal muscle cell nuclei,

Striations = A&I bands

Cross striations in skeletal muscle cells (Slide 211-001)

A band

I band

Z disc

Skeletal muscle cells

211

EM 10; skeletal muscle; 30,000x

1. Mitochondria

2. Sarcoplasmic reticulum

3. Terminal cisternae

Esophagus – skeletal and smooth muscle

137

Connective tissue nerve

EM 10a: Endothelial cells lining capillary with pericyte in the vessel wall; 20,000x

1. Lumen

2. Endothelial cell

3. Tight junction

Contracted skeletal muscle cellshave small I bands

Nerve – muscle interface at the motor end plates

Muscle spindlesstretch receptorsMuscle fibers inside a connective tissue capsule

Slide HISTO007 skeletal muscle cells

Note the motor end plates in several skeletal muscle cells

Nerve – muscle interface at the motor end plates

19753 Muscle spindles

Intrafusal fibers inside the capsule

Muscle spindle #19753

136 Tongue Muscle spindle

Muscle spindles

fibroblasts

capillaries

nerve

Intrafusal fibers inside the capsule

Cardiac muscle cells Skeletal muscle cells

211 225

Intercalated disc = cell attachments

EM 10b

Intercalated disc in cardiac cells of the Heart,

epicardium

225

A band I band

Slide 226 Cardiac muscle cells are striated

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.

Cardiac muscle cellsare branched

Slide 226 Cardiac muscle cells are striated

Cardiac cells can accumulate a high density of lipofuscin granules resulting from incomplete lysosomal digestion within the cell

Cardiac muscle cells

Heart

Internodal connections

Histo0 23 heart muscle

Purkinje fibers

Cardiac muscle cells

Intercalated discs

EM 10b cardiac muscle cells

EM 10b

Intercalated discs

Gap junctions

CARDIAC MUSCLE – Diad located at Z disc

Diad = (T tubule + one end of SER)

TRIAD = (T TUBULE + TWO ENDS OF SER)

Skeletal muscle – triad located at A-I junction

EM 10b

EM 10

Cardiac muscle celldiad

Skeletal muscle celltriad

Test Questions on MuscleWhich is (are) true about striated muscle?

a. The “A” band = dark band = anisotropic to polarized lightb. The “I” band = light band = isotropic to polarized light c. The endomysium is delicate connective tissue around individual myofibrilsd. a & be. a, b, & c

Which types of muscle have nuclei in the center of its cells and are involuntary:

a. Smooth muscleb. Cardiac musclec. Skeletal muscled. a and be. a, b and c

  Which is/are related to stimulation of muscle contraction:

a. Motor end plateb. Gap junctionsc. Purkinje fibers d. a and be. a, b and c

In summary

• 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, 13 th ed. McGraw

Many illustrations in these VIBS Histology YouTube videos were modified from the following books and sources: Many thanks to original sources!

Big Bend National Park, TX

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