Comprehensive Physiology Wiley Online Library

Mechanical and Electrical Properties of Respiratory Muscles

Full Article on Wiley Online Library



Abstract

The sections in this article are:

1 Basic Concepts—Review of Muscle Mechanics
1.1 Muscle Fiber Types
1.2 Mechanics of Muscle
1.3 Electrical Properties of Skeletal Muscle
2 Individual Respiratory Muscles and Their Properties
2.1 General Considerations
2.2 Diaphragm
2.3 Intercostal Muscles
2.4 Sternocleidomastoid and Scalenus Muscles
2.5 Abdominal Muscles
2.6 Other Respiratory Muscles
3 Altered Respiratory Muscle Mechanical Properties in Disease
3.1 Obstructive Lung Disease
3.2 Diseases Characterized by Stiff Lungs
3.3 Neuromuscular Diseases
3.4 Severe Obesity
Figure 1. Figure 1.

Load‐extension or stress‐strain curve of rat gracilis anticus muscle. Mean ± se of 5 muscles.

From Bahler et al.
Figure 2. Figure 2.

Active (upper) and passive (lower) length‐tension curves of rat gracilis muscle. Resting in situ length, 2.6 cm; muscle wt, 50 mg; maximum force, 25 g; stimulation tetanic at 95 Hz; temperature, 17.6°C.

From Bahler et al.
Figure 3. Figure 3.

Active and passive length‐tension curves of dog diaphragmatic strip with intact nerve and blood supply. Both force and length normalized (l0, resting in situ length); stimulation supramaximal via the phrenic nerve at 120 Hz; temperature, 38°C. Average values from 13 dogs.

From Kim et al.
Figure 4. Figure 4.

Active length‐tension curve of frog muscles in relation to sarcomere lengths. (Should be considered together with Fig. A, B in relating changes in thick and thin filament relationships and their overlap to the length‐tension curve.) Arrows are placed opposite striation spacings at which critical stages of filament overlap occur, numbered as in Fig. B.

From Gordon et al.
Figure 5. Figure 5.

A: schematic diagram of sarcomere filaments, indicating nomenclature for relevant dimensions. B: critical stages in increase in overlap between thick and thin filaments as sarcomere shortens.

From Gordon et al.
Figure 6. Figure 6.

Isometric‐twitch and tetanus responses for the inferior rectus (IR), extensor digitorum longus (EDL), diaphragm (DIA), and soleus (SOL) muscles of mouse. Records obtained at optimum length for isometric tetanic contractions at 35°C. Stimulus frequencies for all unfused tetanic contractions (middle panels) were 50 Hz. Stimulus frequencies for fused tetanic contractions (right panels) were IR, 500 Hz; EDL, 500 Hz; DIA, 200 Hz; SOL, 150 Hz.

From Luff
Figure 7. Figure 7.

Normalized isotonic force‐velocity curves of rat gracilis muscle at various lengths of the contractile component, l0′, Resting in situ length.

From Bahler et al.
Figure 8. Figure 8.

Three‐dimensional plot representing dynamic length‐force‐velocity phase space of contractile component of rat gracilis muscle.

From Bahler et al.
Figure 9. Figure 9.

Relationships between force‐velocity curve and the power‐velocity curve, illustrating that there is an optimal velocity at which efficiency of power generation is maximal. Force, velocity, and work are in arbitrary units. Upper panels: dashed curves, situation in which shortening velocities are half those represented by solid curves. Optimum velocity is shifted. Lower panels: dashed curves, situation in which forces but not shortening velocities are halved. Optimal velocity of shortening remains unchanged.

Figure 10. Figure 10.

Length‐tension curves of dog diaphragm, flexor carpi radialis, and sartorius. Whole muscle used with intact nerve and blood supply. Stimulation was supramaximal via nerve at 100 Hz. Temperature, 38°C.

Data from L. M. Klemka, unpublished observations
Figure 11. Figure 11.

Force‐velocity curves for inferior rectus (IR), extensor digitorum longus (EDL), diaphragm (DIA), and soleus (SOL) muscles in mouse. Ordinate is speed of sarcomere shortening and abscissa is isotonic load as fraction of maximum isometric tetanic tension.

From Luff


Figure 1.

Load‐extension or stress‐strain curve of rat gracilis anticus muscle. Mean ± se of 5 muscles.

From Bahler et al.


Figure 2.

Active (upper) and passive (lower) length‐tension curves of rat gracilis muscle. Resting in situ length, 2.6 cm; muscle wt, 50 mg; maximum force, 25 g; stimulation tetanic at 95 Hz; temperature, 17.6°C.

From Bahler et al.


Figure 3.

Active and passive length‐tension curves of dog diaphragmatic strip with intact nerve and blood supply. Both force and length normalized (l0, resting in situ length); stimulation supramaximal via the phrenic nerve at 120 Hz; temperature, 38°C. Average values from 13 dogs.

From Kim et al.


Figure 4.

Active length‐tension curve of frog muscles in relation to sarcomere lengths. (Should be considered together with Fig. A, B in relating changes in thick and thin filament relationships and their overlap to the length‐tension curve.) Arrows are placed opposite striation spacings at which critical stages of filament overlap occur, numbered as in Fig. B.

From Gordon et al.


Figure 5.

A: schematic diagram of sarcomere filaments, indicating nomenclature for relevant dimensions. B: critical stages in increase in overlap between thick and thin filaments as sarcomere shortens.

From Gordon et al.


Figure 6.

Isometric‐twitch and tetanus responses for the inferior rectus (IR), extensor digitorum longus (EDL), diaphragm (DIA), and soleus (SOL) muscles of mouse. Records obtained at optimum length for isometric tetanic contractions at 35°C. Stimulus frequencies for all unfused tetanic contractions (middle panels) were 50 Hz. Stimulus frequencies for fused tetanic contractions (right panels) were IR, 500 Hz; EDL, 500 Hz; DIA, 200 Hz; SOL, 150 Hz.

From Luff


Figure 7.

Normalized isotonic force‐velocity curves of rat gracilis muscle at various lengths of the contractile component, l0′, Resting in situ length.

From Bahler et al.


Figure 8.

Three‐dimensional plot representing dynamic length‐force‐velocity phase space of contractile component of rat gracilis muscle.

From Bahler et al.


Figure 9.

Relationships between force‐velocity curve and the power‐velocity curve, illustrating that there is an optimal velocity at which efficiency of power generation is maximal. Force, velocity, and work are in arbitrary units. Upper panels: dashed curves, situation in which shortening velocities are half those represented by solid curves. Optimum velocity is shifted. Lower panels: dashed curves, situation in which forces but not shortening velocities are halved. Optimal velocity of shortening remains unchanged.



Figure 10.

Length‐tension curves of dog diaphragm, flexor carpi radialis, and sartorius. Whole muscle used with intact nerve and blood supply. Stimulation was supramaximal via nerve at 100 Hz. Temperature, 38°C.

Data from L. M. Klemka, unpublished observations


Figure 11.

Force‐velocity curves for inferior rectus (IR), extensor digitorum longus (EDL), diaphragm (DIA), and soleus (SOL) muscles in mouse. Ordinate is speed of sarcomere shortening and abscissa is isotonic load as fraction of maximum isometric tetanic tension.

From Luff
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John T. Sharp, Robert E. Hyatt. Mechanical and Electrical Properties of Respiratory Muscles. Compr Physiol 2011, Supplement 12: Handbook of Physiology, The Respiratory System, Mechanics of Breathing: 389-414. First published in print 1986. doi: 10.1002/cphy.cp030323