MUSCLE TISSUE
Larry Johnson Texas A&M University
Objectives
• Histologically identify and functionally characterize each
of the 3 types of muscle tissues.
• Describe the organization of the sarcomere as seen in
light and electron microscopy.
• Identify the endomysium, perimysium, and epimysium CT
sleeves in muscle.
• Relate the functional differences of the three muscle cell
types.
From: Douglas P. Dohrman and TAMHSC Faculty 2012 Structure and Function of Human Organ Systems, Histology
Laboratory Manual
MUSCLE
FUNCTION:
•
GENERATION OF CONTRACTILE FORCE
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)
MUSCLE
• DISTRIBUTION:
SKELETAL – STRIATED MUSCLES
MOSTLY ASSOCIATED WITH THE
SKELETON
MUSCLE
• DISTRIBUTION:
SKELETAL – STRIATED MUSCLES
MOSTLY ASSOCIATED WITH THE
SKELETON
CARDIAC – STRIATED MUSCLES
ASSOCIATEWD WITH THE HEART
MUSCLE
• DISTRIBUTION:
SKELETAL – STRIATED MUSCLES
MOSTLY ASSOCIATED WITH THE
SKELETON
CARDIAC – STRIATED MUSCLES
ASSOCIATEWD WITH THE HEART
SMOOTH – FUSIFORM CELLS
ASSOCIATED WITH THE VISCERA,
RESPIRATORY TRACT, BLOOD
VESSELS, UTERUS, ETC.
MUSCLE
HISTOLOGICAL INDENTIFICATION:
SKELETAL MUSCLE – VERY LONG CYLINDRICAL
STRIATED MUSCLE CELLS WITH MULTIPLE
PERIPHERAL NUCLEI
MUSCLE
HISTOLOGICAL INDENTIFICATION:
SKELETAL MUSCLE – VERY LONG CYLINDRICAL
STRIATED MUSCLE CELLS WITH MULTIPLE
PERIPHERAL NUCLEI
CARDIAC MUSCLE – SHORT
BRANCHING STRIATED
MUSCLE CELLS WITH
CENTRALLY LOCATED NUCLEI
MUSCLE
HISTOLOGICAL INDENTIFICATION:
SKELETAL MUSCLE – VERY LONG CYLINDRICAL
STRIATED MUSCLE CELLS WITH MULTIPLE
PERIPHERAL NUCLEI
CARDIAC MUSCLE – SHORT
BRANCHING STRIATED
MUSCLE CELLS WITH
CENTRALLY LOCATED NUCLEI
SMOOTH MUSCLE – CLOSELY
PACKED SPINDLE-SHAPED
CELLS WITH A SINGLE
CENTRALLY PLACED NUCLEUS
AND CYTOPLASM THAT
APPEARS HOMOGENEOUS
BY LIGHT MICROSCOPY
MUSCLE
HISTOLOGICAL INDENTIFICATION:
SKELETAL MUSCLE – VERY LONG CYLINDRICAL
STRIATED MUSCLE CELLS WITH MULTIPLE
PERIPHERAL NUCLEI
CARDIAC MUSCLE – SHORT
BRANCHING STRIATED
MUSCLE CELLS WITH
CENTRALLY LOCATED NUCLEI
SMOOTH MUSCLE – CLOSELY
PACKED SPINDLE-SHAPED
CELLS WITH A SINGLE
CENTRALLY PLACED NUCLEUS
AND CYTOPLASM THAT
APPEARS HOMOGENEOUS
BY LIGHT MICROSCOPY
Myoepithelial cells
Muscle Tissue
• Muscle cells specialized for contraction with apparatus of actin
and myosin proteins.
• 3 types:
Skeletal Muscle
Smooth Muscle
Cardiac Muscle
Longitudinal sections
- Peripheral nuclei
- Striations
- No branching
Longitudinal sections
- Central nuclei (often
fusiform)
- Meshwork
appearance of cells
- No striations
Longitudinal sections
- Central nuclei (often
elongated)
- Striations
- Branching cells
- Intercalated discs
Cross section
- Peripheral nuclei
- Massive cytoplasm
Cross section
- Central nuclei
- Low cytoplasm to
nucleus ratio
Cross section
- Central nuclei
- High cytoplasm to
nucleus ratio
Slide 11: Skeletal muscle (longitudinal and
cross sections)
Muscle fibers with peripheral
nuclei
Capillary
Cross sections of
muscle fibers with peripheral nuclei
Slide 052: Skeletal muscle (longitudinal
and cross sections)
Muscle fibers with peripheral
nuclei
Capillary
Cross striations
(A and I bands)
Slide 052: Skeletal muscle (longitudinal
and cross sections)
Muscle fibers with peripheral
nuclei
Capillary
Cross striations
(A and I bands)
The increase in muscle mass during exercise results from stimulating
formation of new myofibrils and enlargement in the diameter of individual
muscle fibers (hypertrophy = increase in size).
CONNECTIVE TISSUE LAYERS OF
SKELETAL MUSCLE
•
EPIMYSIUM - COARSE CT
EPIMYSIUM
CONNECTIVE TISSUE LAYERS OF
SKELETAL MUSCLE
•
•
EPIMYSIUM - COARSE CT
PERIMYSIUM - LESS COARSE
CT
PERIMYSIUM
EPIMYSIUM
CONNECTIVE TISSUE LAYERS OF
SKELETAL MUSCLE
•
•
•
EPIMYSIUM - COARSE CT
PERIMYSIUM - LESS COARSE
CT
ENDOMYSIUM - DELICATE CT
PERIMYSIUM
EPIMYSIUM
ENDOMYSIUM
CONNECTIVE TISSUE LAYERS OF
SKELETAL MUSCLE
EPIMYSIUM, PERIMYSIUM, and ENDOMYSIUM
Slide 11: Skeletal muscle (longitudinal and
cross sections)
Epimysium
Perimysium
Endomysium
Slide 052 Skeletal muscle (longitudinal
and cross sections)
Perimysium
Endomysium
with its capillaries
CONNECTIVE
TISSUE
connect
LAYERS OF
SKELETAL
MUSCLE
•
ENDOMYSIUM
CONNECTIVE TISSUE LAYERS OF
SKELETAL MUSCLE
PERIMYSIUM
CONNECTIVE TISSUE LAYERS OF
SKELETAL MUSCLE
PERIMYSIUM
052
•
ENDOMYSIUM
Striations in skeletal muscle 052
Skeletal muscles have striations, peripheral nuclei, same
thickness throughout their length and do not branch.
Specialized for powerful and rapid contraction. Voluntary.
Found attached to the skeleton.
Slide 12: Skeletal muscle
(phosphotungstic acid/hematoxylin)
Sarcomere:
Z line to Z line
Z line is
In the I band
I band
A band
STRIATED MUSCLE
CARDIAC
SKELETAL
“A” BAND = dark band
ANISOTROPIC = DOES
ALTER POLARIZED LIGHT
(BIREFRINGENT)
A
STRIATED MUSCLE
CARDIAC
SKELETAL
“A” BAND = dark band
ANISOTROPIC = DOES
ALTER POLARIZED LIGHT
(BIREFRINGENT)
“I” BAND = light band
ISOTROPIC = DOES NOT
ALTER POLARIZED LIGHT
A
I
STRIATED
MUSCLE
(SKELETAL)
A
SARCOMERES ARE
ORGANIZED FOR
RAPID AND HIGHLY
CONTROLLED
CONTRACTION
I
SKELETAL MUSCLE
cell structure
SKELETAL MUSCLE
SKELETAL MUSCLE
INTERMEDIATE FILAMENTS –
FUNCTION in muscle cells
• MYOFIBRIL ORGANIZATION – MUSCLE
cells
INTERMEDIATE FILAMENTS –
FUNCTION in muscle cells
• MYOFIBRIL ORGANIZATION – MUSCLE
cells
Cell =
CONTRACTION OF
THE SARCOMERE
THIN FILAMENT
ACTIN (F-ACTIN)
TROPOMYOSIN
TROPONIN
T - ATTACHES TO
TROPOMYOSIN
C - BINDS CALCIUM IONS
I - INHIBITS ACTIN-MYOSIN
INTERACTION
The stoppage of the neural impulse and
depletion of free calcium ends the actinmyosin crossbridge cycle in skeletal
muscle. ATP is required in this process.
CALCIUM
REGULATION
TRANVERSE (T) TUBULE
(INVAGINATION OF
SARCOLEMMA)
TRANSMIT DEPOLARIZATION
OF MEMBRANE DEEP
INTO THE CELL
SARCOPLASMIC RETICULUM
(SER OF CELL)
RELEASE CA++ FOR
CONTRACTION - THEN
RECOVER CA++
AFTER CONTRACTION
TRIAD = (T TUBULE AND TWO
ENDS OF SER)
EM 29 : Skeletal
muscle
052
EM 46 and 47 : Skeletal muscle
STIMULATION OF MUSCLE CELLS
Slide 13: Skeletal Muscle – muscle
spindles (trichrome)
Intrafusal muscle
fibers
Muscle spindle:
(stretch receptors)
Nerve fibers
INNERVATION OF MUSCLE
MUSCLE SPINDLE
MUSCLE
SPINDLE
Intracapsular
fibers
SMOOTH MUSCLE
SMOOTH MUSCLE
Has a PAS +
basement membrane
Slide 35: Urinary bladder
Muscularis externa
(smooth muscle)
Smooth muscle fibers with central nuclei
Smooth muscles are fusiform with tapered ends, single, central nuclei, and no
striations. Involuntary. Found in sphincters and sheets of internal visceral
organs and glands.
Slide 63: Appendix
Submucosa
Muscularis externa
Smooth muscle layer
arrangement in tubular organs
The layering of smooth muscle in the gut is responsible
for contractions which mix and propel luminal contents forward.
EM 49: Smooth muscle
Actin
Myosin
SMOOTH MUSCLE
MUSCULAR ARTERY
Skeletal
Muscle
Smooth
muscle
CARDIAC MUSCLE IS STRIATED MUSCLE
•INTERCALATED DISC
• FASCIA ADHERENS
• MACULAE ADHERENS
• GAP JUNCTIONS - LATERAL PORTION
CARDIAC MUSCLE
INTERCALATED DISC
The intercalated discs enables coordinated function via gap junctions to
facilitate energy and calcium conductance between neighboring myocytes.
pulmonary artery in the
lungs of a rat
INTERCALATED
DISC
pulmonary artery in the
lungs of a rat
nucleus
mitochondria
INTERCALATED
DISC
Slide 14: Heart & EM 48: Heart
Intercalated discs
CARDIAC MUSCLE – Diad located at Z line
Diad = (T tubule +
one end of SER)
REGENERATION OF MUSCLE
Which type of muscle cells can be replaced in
adults?
•SMOOTH – LOTS
•SKELETAL – SOME
•CARDIAC – NONE
Clinical Correlation
Ischemic heart disease is one of the
most significant health problems in the
US. Coronary artery thrombosis
usually precedes and precipitates a
myocardial infarct, resulting in the
death of cardiac myocytes. Eventually
scar tissue is formed and there is
some loss of contractility.
Image taken from adultstemcellawareness.wordpress.com
Lacking muscle mesenchymal satellite cells, adult mammalian
cardiac muscle has little potential to regenerate after injury.
Damage is replaced by proliferating fibroblasts and connective
tissue growth, forming myocardial scars.
Summary of MUSCLE
shapes and excitations of types
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.
•
A.L. Mescher 2013 Junqueira’s Basis Histology text and atlas, 13th ed. McGraw
•
Douglas P. Dohrman and TAMHSC Faculty 2012 Structure and Function of Human Organ Systems, Histology Laboratory
Manual - Slide selections were largely based on this manual for first year medical students at TAMHSC
The end!