Difference Between Red and White Muscle: Composition, Function

What Are Red And White Muscles?

Red and white muscles are the two major types of skeletal muscle fibres identified according to their looks and operation. Muscles facilitate motion, posture, and other physiological functions of the body. Three major kinds of muscles are there in the body: skeletal (voluntary m striated), smooth (involuntary, non-striated), and cardiac (involuntary, striated). Skeletal muscles are those used for voluntary body movements and posture. Characterised by a striated appearance, these muscles anchor into bones via tendons; they are known to fatigue more easily. Slow twitch fibres, on the other hand, especially red muscles, hold many mitochondria and much myoglobin and are reserved for endurance. Fast twitch fibres, white muscles, contain fewer mitochondria and are meant for short, powerful movements.

Red Muscle Fibres

The properties of Red Muscle Fibers are discussed below-

Characteristics

They have lots of myoglobin, so these fibres are red and well adapted for oxygen storage; intensive vascularisation guarantees constant oxygen delivery with blood and the necessary nutrients; much mitochondria for aerobic energy production.

Functionality

Red muscle fibres have a slow contraction and are supposed to perform activities for long-lasting durations. It is highly enduring as it maximally uses oxygen optimally thereby resisting fatigue. From this, its source of energy is aerobic respiration, hence maintaining activity for a long while.

Examples

It is these fibres that are dominant in the muscles of posture, for example, the spinal erectors of the back. They are also dominant in endurance-type activities such as marathon running and swimming, where contractions of moderate intensity must be maintained for extended durations.

White Muscle Fibres

The properties of White Muscle Fibers are discussed below-

Characteristics

White muscle fibres, or fast-twitch fibres, have low myoglobin content, which gives them a pale appearance. They receive less blood supply compared to red muscle fibres and contain fewer mitochondria. This begets less-suited characteristics for prolonged activities but adequate efficiency for short, intense exertions.

Functionality

Such fibres are formed in a way to contract quickly and exert much force and, thus, are capable of making rapid and strong movements. But, on the contrary, they have a very low duration of fatigue and, therefore, get tired very easily. They mainly rely on the process of anaerobic respiration by cells in the generation of energy and can thus support periods of activity that last very short durations of time without oxygen.

Examples

White muscle fibres are used in muscles for fast, explosive activities, such as sprinting and weight lifting. They are important in activities that require instantaneous, high-intensity exertion rather than endurance over a length of time.

Comparison Of Red And White Muscle Fibres

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