ANAT2241 Muscle Tissue

From Embryology

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ANAT2241 This practical support page content is not part of the virtual science practical class and provides additional information for student self-directed learning purposes. All practical class pages are located on Moodle - ANAT2241

General Objective

To know the structure and ultrastructure of the three main types of muscle and how it relates to their varied functions.

Specific Objectives

  1. To identify striated skeletal (striated), cardiac and smooth muscle on the basis of histological features.
  2. To distinguish connective tissue in association with muscle cells and fascicles of muscle cells.
  3. To describe the ultrastructural features of the different types of muscle cells.

Learning Activities

Examine electron micrographs of skeletal muscle in longitudinal section (LS) and identify the following features:

  1. A band (dark staining; anisotropic)
  2. I band (light staining; isotropic)
  3. H band (pale zone in centre of A band)
  4. M line in centre of H band
  5. Z discs (in centre of I band) delineating the sarcomere
  6. Sarcoplasmic reticulum
  7. T tubules (transverse tubular system) and triads.

Virtual Slides: Muscle Tissue

Skeletal muscle structure cartoon.jpg Skeletal muscle histology 016.jpg
Skeletal muscle structure cartoon Skeletal muscle sarcomeres


Histology Links: Skeletal Muscle | Cardiac Muscle | Smooth Muscle

Muscle Contraction

Skeletal muscle sarcomeres

Skeletal, cardiac and smooth muscle all contract using the same mechanism: actin thin filaments being drawn together by myosin thick filaments.

  • In skeletal and cardiac muscle these thick and thin filaments are organised in series into sarcomeres along the length of the muscle cell. This regular organization gives the muscle cells a striated appearance.
  • In smooth muscle these thick and thin filaments are not organised into sarcomeres but are spread throughout the cell cytoplasm.

This animation shows the molecular interactions that occur within the skeletal muscle sarcomere between actin and myosin during skeletal muscle contraction. This irregular organization gives the muscle a non-striated appearance.

Legend

  • Moving blob and stick - myosin complex.
  • Moving blob and stick - myosin complex with ATPase activation.
  • Ball binding myosin and splitting - ATP losing a phosphate to form ADP.
  • Twisted string of beads - actin helix.
  • Blue string - tropomyosin.
  • Beads stacked on large bead on blue string - troponin.
  • Small ball binding troponin - Calcium ion (Ca2+).
  • Grey pyramid - Magnesiun ion (Mg2+).
Actin myosin crossbridge 3D animation.gif


Skeletal Muscle Histology

Muscle Histology: Muscle Development | Human HE x4 longitudinal and transverse | Human HE x40 transverse | Human HE x40 longitudinal | Human HE x40 longitudinal | Human HE x4 longitudinal and transverse | Muscle Spindle HE x40 | Human HE x40 | Human HE x40 | Human HE x40 | Human HE x100 | Human HE x100 | Fetal human muscle | Myotendinous junction label | Myotendinous junction HE x40 | Whipf 1 | Whipf 2 | Whipf 3 | Tongue HE x10 transverse | Tongue x100 | Muscle spindle HE x20 | Muscle spindle HE x40

Electron Microscopy - Virtual Slides

Skeletal Muscle EM1

SkeletalMuscleEM01-icon.jpg

 ‎‎Mobile | Desktop | Original

Skeletal Muscle | EM Slides
Skeletal Muscle EM2

SkeletalMuscleEM02-icon.jpg

 ‎‎Mobile | Desktop | Original

Skeletal Muscle | EM Slides
Skeletal Muscle EM3

SkeletalMuscleEM03-icon.jpg

 ‎‎Mobile | Desktop | Original

Skeletal Muscle | EM Slides
Skeletal Muscle EM4

SkeletalMuscleEM04-icon.jpg

 ‎‎Mobile | Desktop | Original

Skeletal Muscle | EM Slides
Skeletal Muscle EM5

SkeletalMuscleEM05-icon.jpg

 ‎‎Mobile | Desktop | Original

Skeletal Muscle | EM Slides

Muscle Fibre Types

Muscle fiber types

Muscle fiber types

  • type IIB, IIA, IIX, and I fibres - based only on the myosin ATPase activity.
    • Type I fibres appear red, due to the presence of myoglobin.
    • Type II fibres appear white, due to the absence of myoglobin and their glycolytic nature.
  • A group of individual myofibres within a muscle will be innervated by a single motor neuron (motor unit).
  • The electrical properties of the motor neuron will regulate the contractile properties of all associated myofibres.


Cardiac Muscle Histology

Cardiac muscle histology.jpg

Cardiac muscle histology

Image of primate heart stained with Alizarin blue.
  • Red Blood Cells (orange cells) Cardiac Muscle Cells (blue)
  • Cardiac muscle cells are cut longitudinally.
  • At high magnification see both striations and the large nuclei of the cardiac muscle cells.
  • Follow the course of individual cardiac muscle cells and note fine, dark blue lines which seem to cross (traverse) the fibres.
  • Intercalated Discs that connect the individual muscle cells and permit the conduction of electrical impulses between the cells.
    • seen in longitudinal sections.

Heart histology 002.jpg Heart histology 004.jpg

Heart histology 003.jpg Heart histology 001.jpg

Unlabeled Images

Electron Microscopy - Cardiac Muscle

Unlabelled Image Labelled Image
Cardiac muscle EM01.jpg Cardiac muscle EM02.jpg
Original image X 15,000.
  • In D - Intercalated disc, the two lower cells are joined end to end by a typical steplike intercalated disc.
  • Mt - Rows of mitochondria appear to divide the contractile substance into myofibril-like units but, unlike the true myofibrils of skeletal muscle, these branch and rejoin and are quite variable in width.
  • Lp - Lipid droplets somewhat distorted in specimen preparation are found between the ends of the mitochondria.
  • Cap - Capillary.
  • Image Top - In a cardiomyocyte (cardiac muscle cell) 2 contractile units (sarcomere) are shown by white arrows. The A and I bands, shown by black arrows, are the regions visible by light microscope as cross-striations.
  • Image Bottom - The 2 cardiomyocytes (cardiac muscle cells) are coloured (labeled cell 1 and cell 2) and are joined by an intercalated disc.
  • Image Bottom Right - A capillary (red) enclosed by an endothelial cell and its basement membrane contains a red blood cell.

Smooth Muscle Histology

Smooth Muscle Histology: Labeled Colon low | Labeled Colon high | Colon x40 | Colon x40 | Ileum x10 | Oesophagus x10 | Seminiferous tubule x40 | Uterus myometrium x10 | Uterus myometrium x40 |


Links: Smooth Muscle Development | Smooth Muscle Histology

Gastrointestinal Tract Wall

The gastrointestinal tract consists of two thick outer muscle layers (longitudinal and circular) and a thin muscularis mucosa layer.

Smooth muscle histology 001.jpg Smooth muscle histology 002.jpg


Course Links

Moodle - ANAT2241 - 2019

Histology Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | ANAT2241 Support | Histology | Histology Stains | Embryology Glossary


Common Histology Stains  
Histology Stains - Common Stains and Their Reactions
Stain
Nucleus
Cytoplasm
Collagen
RBCs
Other
Haematoxylin
blue
-
-
-
mucins - light blue
Eosin
-
pink
pale pink
bright red
colloid - pinkmuscle - red
Iron Haematoxylin
blue/black
-
-
-
Van Gieson
-
brown/yellow
red
yellow
muscle: yellow/browncartilage - pink
Verhoeff's Elastin
black
-
-
-
elastic fibres - black
Tartrazine
-
yellow
yellow
yellow
Silver Impregnation
-
-
grey/brown
-
reticular fibres - black
Methyl Green
dark green
light green
light green
green
Nuclear Fast Red
red
pink
pink
pink
Gomori's Trichrome
purple/red
purple
green
red
keratin - redmuscle - purple/red
Heidenhain's Azan
red
purple/red
deep blue
red
muscle - red
Osmium Tetroxide
-
-
brown
brown
myelin, lipids - black
Alcian Blue
-
-
-
-
mucins, - blue
Periodic acid-Schiff (PAS)
-
-
pink
-
mucins, glycogen, glycocalyx - magenta
Phosphotungstic Acid-Hematoxylin (PTAH)
blue
-
red
blue
muscle bands - blue
Masson's Trichrome
blue/black
red
green/blue
red
cartilage, mucins - blue or green; muscle - red
Luxol Fast Blue
-
-
-
variable
myelin - blue
Aldehyde Fuchsin
-
-
-
-
elastic fibres, mast cells - deep purple
Light Green
-
-
light green
-
Gallocyanin
dark blue
-
-
-
nucleic acids, Nissl granules - dark blue
Romanowsky (e.g. Leishman's)
blue
pink
acidophils - red, basophils - blue, azurophilic - purple
Aldehyde Pararosanilin elastic fibres - purple
Haematoxylin and Eosin
One of the most common staining techniques in pathology and histology. Acronym "H and E" stain. (H&E, HE).


Haematoxylin
  • Stains nuclei blue to dark-blue.
  • Stains the matrix of hyaline cartilage, myxomatous, and mucoid material pale blue.
  • Stains myelin weakly but is not noticeable if combined with eosin stain.
  • combined with Orange G (H & Or. G.) instead of eosin, specifically stains the granules of acidophilic cells of the adenohypophysis (anterior pituitary).
Eosin
  • Stains cytoplasm pink to red; red blood cells are also bright red.
  • Common counterstain to hematoxylin.
  • Stain intensity varies with the formula as well as the fixative.

Practical Support

Pages can be accessed from any internet connected computer.

ANAT2241 Support Links: The Virtual Microscope | Covering and Lining Epithelia | Glandular Epithelia | CT Components | CT Types | Bone, Bone Formation and Joints | Muscle | Nervous | Blood | Eye | Cardiovascular | Respiratory | Integumentary | Gastrointestinal | Gastrointestinal Organs | Lymphatic and Immune | Endocrine | Urinary | Female Reproductive | Male Reproductive | Histology Stains | Histology Drawings | Practicals Health and Safety 2013 | Moodle - 2019


ANAT2241 This practical support page content is not part of the science practical class and provides only background information for student self-directed learning purposes.


Cite this page: Hill, M.A. (2024, March 19) Embryology ANAT2241 Muscle Tissue. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/ANAT2241_Muscle_Tissue

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G