Maximus Gage
Muscle fibres are long, cylindrical-shaped fibres that range in diameter from 0.02 to 0.08 mm. In some muscles, the fibres run the entire length of the muscle, up to several tens of centimetres long. Skeletal muscle fibres are among the largest cell types, ranging in diameter from several microns to thousands of microns. The size of muscle fibres is highly variable, and while diffusion appears to limit maximal fibre size, there is no paradigm for the control of minimal size.
| Characteristics | Values |
|---|---|
| Diameter | 0.02 to 0.08 mm |
| Length | Several tens of centimetres |
| Cell type | Skeletal muscle fibres are among the largest |
| Colour | White |
Explore related products
What You'll Learn
Muscle fibres are 0.02 to 0.08 mm in diameter
Skeletal muscle fibres are among the largest cell types, ranging from several microns to thousands of microns in diameter. The maximal fibre size is limited by diffusion constraints associated with aerobic metabolism, which relies on the transport of O2 from the blood to the mitochondria and subsequent diffusion of ATP from mitochondria to cellular ATPases.
The optimal fibre size hypothesis posits that the reduced surface area to volume (SA:V) in larger fibres reduces the metabolic cost of maintaining the membrane potential. This means that fibres attain an optimal size that minimises metabolic cost while avoiding diffusion limitation.
Muscle fibres have a large diameter and high amounts of glycogen, which is used in glycolysis to generate ATP quickly to produce high levels of tension.
Building Muscle: Understanding the Science of Strength Training
You may want to see also
Explore related products
Skeletal muscle fibres are among the largest cell types
The size of skeletal muscle fibres is highly variable, and while diffusion appears to limit maximal fibre size, there is no clear explanation for the control of minimal size. The optimal fibre size hypothesis suggests that larger fibres have a reduced surface area to volume ratio (SA:V), which lowers the metabolic cost of maintaining the membrane potential. This hypothesis aims to explain the very large fibres found in the white muscle of some cold-water fishes.
Skeletal muscle fibres are multi-nucleated syncytia, and their size may be limited by diffusion constraints associated with aerobic metabolism. Aerobic metabolism relies on the transport of oxygen from the blood to the mitochondria and the subsequent diffusion of ATP from mitochondria to cellular ATPases.
FG muscle fibres, a specific type of muscle fibre, have a large diameter and high amounts of glycogen, which allows them to produce rapid, forceful contractions for quick, powerful movements. However, these fibres fatigue quickly and can only be used for short periods.
Hydration and Muscle Relaxation: Water's Impact
You may want to see also
Explore related products
The 'optimal fibre size hypothesis'
Muscle fibres are long and cylindrical, ranging from 0.02 to 0.08 mm in diameter. In some muscles, the fibres run the entire length of the muscle, up to several tens of centimetres long.
The optimal fibre size hypothesis was proposed by Johnston et al. to explain the very large fibres found in the white muscle of some cold-water fishes. The hypothesis states that fibre size represents a balance between the need for small fibres that promote rapid diffusive flux and the potential metabolic cost savings associated with large fibres that have a low surface area-to-volume ratio (SA:V:V).
Muscle accounts for 20-30% of total resting O2 consumption in humans. A major source of ATP demand in muscle is the maintenance of the membrane potential by the Na+-K+-ATPase. This is the only sizable ATP sink in resting muscle that is associated with the sarcolemmal membrane and is, therefore, potentially sensitive to fibre SA:V.
The optimal fibre size hypothesis posits that the reduced SA:V in larger fibres reduces the metabolic cost of maintaining the membrane potential. Therefore, fibres attain an optimal size that minimises metabolic cost while avoiding diffusion limitation. Evidence for this hypothesis has been found by examining changes during hypertrophic fibre growth in metabolic cost and activity of the Na+-K+-ATPase in white skeletal muscle from crustaceans and fishes. It was found that larger fibres are metabolically cheaper to maintain, and the cost of maintaining the membrane potential is proportional to fibre SA:V.
Waist Training: Friend or Foe to Core Muscles?
You may want to see also
Explore related products
FG fibres are used to produce rapid, forceful contractions
Muscle fibres are long and cylindrical, ranging from 0.02 to 0.08 mm in diameter. In some muscles, the fibres run the entire length of the muscle, up to several tens of centimetres long.
The optimal fibre size hypothesis posits that larger fibres are metabolically cheaper to maintain, as they have a reduced surface area to volume ratio, lowering the metabolic cost of maintaining the membrane potential. This hypothesis was proposed to explain the very large fibres found in the white muscle of some cold-water fishes.
FG fibres are just one type of muscle fibre, and most muscles possess a mixture of fibre types. The predominant fibre type in a muscle is determined by the primary function of that muscle.
Walking's Impact: Muscle Breakdown or Growth?
You may want to see also
Explore related products
Muscle fibres are cylindrical-shaped
Skeletal muscle fibres are among the largest cell types. The size of these fibres is highly variable, and while diffusion appears to limit maximal fibre size, there is no paradigm for the control of minimal size. The optimal fibre size hypothesis posits that the reduced surface area to volume (SA:V) in larger fibres reduces the metabolic cost of maintaining the membrane potential. This means that fibres attain an optimal size that minimises metabolic cost while avoiding diffusion limitation.
In some cases, muscle fibres can be very large. For example, Johnston et al. proposed the 'optimal fibre size hypothesis' to explain the very large fibres found in the white muscle of some cold-water fishes. This hypothesis states that fibre size represents a balance between the need for small fibres that promote rapid diffusive flux and potential metabolic cost savings associated with large fibres that have a low SA:V.
Muscle fibres have a large diameter and possess high amounts of glycogen, which is used to generate ATP quickly to produce high levels of tension.
Muscle Contractions: The Science of Movement and Strength
You may want to see also
Frequently asked questions
Muscle fibres are between 0.02 and 0.08 mm in diameter.
Muscle fibres can be several centimetres long.
No, muscle fibres vary in size.
Muscle fibres are cylindrical in shape.
