Muscles and tendons
Muscles - specialised bundles of proteins - are involved in all kinds of biological processes, from locomotion to squeezing food through the digestive tract. We’ve chosen seven images that put muscles and tendons under the microscope.
Image research by Benjamin Thompson and Chrissie Giles; captions adapted by Chrissie Giles. All of the images are free to use in your classroom. For more scientific and medical images, see Wellcome Images.
Cardiac muscle
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IMAGE 1 of 7
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A transmission electron micrograph showing a longitudinal section of cardiac (heart) muscle, in which the sarcomere structure and a large intercalated disc can be seen.
Credit: Professor Giorgio Gabella, Wellcome Images.
Credit: Professor Giorgio Gabella, Wellcome Images.
Relaxed skeletal muscle
IMAGE 2 of 7
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A colour-enhanced transmission electron micrograph of myofibrils in an uncontracted skeletal muscle cell (muscle fibre), showing the structure of the sarcomere with its dark and light bands between the two Z-discs.
Credit: University of Edinburgh, Wellcome Images.
Credit: University of Edinburgh, Wellcome Images.
Striated muscle
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IMAGE 3 of 7
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A light micrograph of stained longitudinal section through striated muscle.
Credit: Spike Walker, Wellcome Images.
Credit: Spike Walker, Wellcome Images.
Glycogen stored in muscle
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IMAGE 4 of 7
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A transmission electron micrograph showing glycogen storage in a muscle cell. Some glycogen granules are dispersed around the many mitochondria in between the contractile myofibrils, but most of the glycogen is in a large area on the edge of the cell.
Credit: Mike Kayser, Wellcome Images.
Credit: Mike Kayser, Wellcome Images.
Historical experiments on frog nerves
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IMAGE 5 of 7
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Galvani’s experiments on the sciatic nerve of frogs. This was the first detection of galvanic currents. From ‘Memorie sulla elettricita animale’ by Luigi Galvani (1797, Bologna).
Credit: Wellcome Library, London.
Credit: Wellcome Library, London.
Muscle cross-section
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IMAGE 6 of 7
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A diagram of a cross-section of a muscle showing fibres.
Credit: Miles Kelly Art Library, Wellcome Images.
Credit: Miles Kelly Art Library, Wellcome Images.
Ruptured tendon
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IMAGE 7 of 7
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A confocal image showing damaged collagen fibres in a ruptured tendon. The area of wavy fibres to the lower right shows the normal, healthy appearance of tendon. The waviness allows the whole tendon to have a small amount of elasticity (between 2 and 10 per cent): the collagen fibres themselves do not stretch.
Credit: Martin Knight, Wellcome Images.
Credit: Martin Knight, Wellcome Images.