Differences between Red and White skeletal muscle fibers

S.N.	Red Muscle Fibers	White Muscle Fibers
1.	They are dark red with abundant pigment, myoglobin.	They are light in color as they have very little myoglobin.
2.	They are comparatively thinner.	They are much thicker.
3.	They have abundant and larger mitochondria.	Their mitochondria are much lesser in number and smaller in size.
4.	They have a high content of cytochrome.	They have a low content of cytochrome.
5.	They have poorly formed sarcoplasmic reticulum.	Their sarcoplasmic reticulum is well formed.
6.	They have low content or storage of glycogen.	They have abundant glycogen granules.
7.	Oxygen is stored in myoglobin as oxymyoglobin which is later released for oxidation during muscle contraction.	They have little or no storage of oxygen.
8.	They get ATP or energy by aerobic respiration for their contraction.	They get ATP or energy for contraction mainly by anaerobic respiration.
9.	There is little or less accumulation of lactic acid in red muscle fibers.	They accumulate lactic acid produced during strenuous work.
10.	They undergo slow sustained contraction for long periods.	They undergo fast contraction for short periods.
11.	They don’t get fatigued with work.	They get fatigued with work very soon.
12.	They are innervated by thin, slow-conducting nerve fibers.	They are innervated by thick, fast-conducting nerve fibers.
13.	They have a very rich blood supply.	They have a very poor blood supply.
14.	e.g. extensor muscles of the back in man	e.g. extra-ocular muscles

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