Differences Between Red And White Muscle Fibres

Differences Between Red And White Muscle Fibres:

The following are the points of difference between Red And White Muscle Fibres-

Red Muscle Fibre (Tonic)White Muscle Fibre (Twitch)
It is thin and narrow.It is thick and broad.
Due to the presence of myoglobin (a heme-protein), these are dark red in colour. Oxygen combines with myoglobin to form oxymyoglobin which releases oxygen during muscular contraction and again converted into myoglobin.Light coloured as do not have myoglobin so no oxygen is stored.
Have abundant Mitochondria as depend upon the energy provided by aerobic cell respiration.Have less number of Mitochondria as depend upon the energy provided by the glycolytic pathway.
Perform slow sustained contraction over a long period.Perform fast strenuous contractions for a short duration.
They are slow to contract and slow to get fatigued.These are early to contract and early to fatigue due to lactic acid.
They have more blood capillaries.They have fewer blood capillaries.
They have less sarcoplasmic reticulum.They have more sarcoplasmic reticulum.
They are innervated by their slow conducting nerve fibres.They are innervated by thick, fast conducting nerve fibres.
Less accumulation of lactic acid.More accumulation of lactic acid during heavy exercises.
Examples- Extensor muscles on the back of the human body and flight muscles of kites, pigeons etc.Examples- Eyeball muscles of human and flight muscles of a sparrow.

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