John J. Videler
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780199299928
- eISBN:
- 9780191714924
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199299928.001.0001
- Subject:
- Biology, Ornithology
Bird flight has always intrigued mankind. This book provides an up-to-date account of the existing knowledge on the subject, offering new insights and challenges some established views. A brief ...
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Bird flight has always intrigued mankind. This book provides an up-to-date account of the existing knowledge on the subject, offering new insights and challenges some established views. A brief history of the science of flight introduces the basic physical principles governing aerial locomotion. This is followed by chapters on the flight-related functional morphology. The anatomy of the flight apparatus includes the wings, tail, and body. Treatment of the wings emphasizes the difference in shape of the arm and hand part. The structural complexity and mechanical properties of feathers receive special attention. Aerodynamic principles used by birds are explained in theory by applying Newton’s laws, and in practice by showing the direction and velocity of the flow around the arm and hand wing. The Archaeopteryx fossils remain crucial to the understanding of the evolution of bird flight despite the recent discovery of a range of well-preserved ancient birds. A novel hypothesis explaining the enigmatic details of the Archaeopteryx remains and challenges established theories regarding the origin of bird flight. Take-off, flapping flight, gliding, and landing are the basic ingredients of bird flight, and birds use a variety of flight styles from hovering to soaring. Muscles are the engines that generate the forces required to control the wings and tail, and to work during flapping motion. The energy required to fly can be estimated or measured directly, and a comparison of the empirical results, provides insights into the trend in metabolic costs of flight of birds varying in shape and mass from hummingbirds to albatrosses.Less
Bird flight has always intrigued mankind. This book provides an up-to-date account of the existing knowledge on the subject, offering new insights and challenges some established views. A brief history of the science of flight introduces the basic physical principles governing aerial locomotion. This is followed by chapters on the flight-related functional morphology. The anatomy of the flight apparatus includes the wings, tail, and body. Treatment of the wings emphasizes the difference in shape of the arm and hand part. The structural complexity and mechanical properties of feathers receive special attention. Aerodynamic principles used by birds are explained in theory by applying Newton’s laws, and in practice by showing the direction and velocity of the flow around the arm and hand wing. The Archaeopteryx fossils remain crucial to the understanding of the evolution of bird flight despite the recent discovery of a range of well-preserved ancient birds. A novel hypothesis explaining the enigmatic details of the Archaeopteryx remains and challenges established theories regarding the origin of bird flight. Take-off, flapping flight, gliding, and landing are the basic ingredients of bird flight, and birds use a variety of flight styles from hovering to soaring. Muscles are the engines that generate the forces required to control the wings and tail, and to work during flapping motion. The energy required to fly can be estimated or measured directly, and a comparison of the empirical results, provides insights into the trend in metabolic costs of flight of birds varying in shape and mass from hummingbirds to albatrosses.
Haruo Sugi (ed.)
- Published in print:
- 1998
- Published Online:
- March 2012
- ISBN:
- 9780198523970
- eISBN:
- 9780191724480
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198523970.001.0001
- Subject:
- Neuroscience, Techniques
Despite extensive physiological, biochemical, and structural studies, the mechanisms of muscle contraction operating in living muscle fibres are still not clearly understood. This book aims to ...
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Despite extensive physiological, biochemical, and structural studies, the mechanisms of muscle contraction operating in living muscle fibres are still not clearly understood. This book aims to describe and assess various experimental methods currently used in the field of muscle research. For each method discussed, there is a comprehensive description of its advantages, problems, and limitations. Each chapter also contains a summary of the central results that have been obtained using each method.Less
Despite extensive physiological, biochemical, and structural studies, the mechanisms of muscle contraction operating in living muscle fibres are still not clearly understood. This book aims to describe and assess various experimental methods currently used in the field of muscle research. For each method discussed, there is a comprehensive description of its advantages, problems, and limitations. Each chapter also contains a summary of the central results that have been obtained using each method.
Walter Herzog
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195395273
- eISBN:
- 9780199863518
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195395273.003.0008
- Subject:
- Neuroscience, Sensory and Motor Systems
The control of joint movements through muscles represents a mathematically redundant problem: that is, there are more muscles than are strictly required for a given task. However, despite this ...
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The control of joint movements through muscles represents a mathematically redundant problem: that is, there are more muscles than are strictly required for a given task. However, despite this apparent redundancy, movements are performed with a stereotypical pattern of muscle activation and synergistic force sharing. Through direct measurement of multiple muscle forces in freely moving animals, this chapter demonstrates that force sharing patterns depend crucially on the mechanical properties of the muscles: the force-length and force-velocity relationships. Using optimal control theory, force sharing patterns can now be predicted confidently when the mechanical properties of the muscles and their instantaneous contractile conditions are accurately represented in the cost functions used to determine force sharing patterns. Although the mechanical properties and instantaneous contractile conditions of muscles are easy to determine in animal models of motor control, force-length and force-velocity properties for individual human skeletal muscles are still hard to obtain, and the instantaneous contractile properties of in vivo human muscle fascicles during dynamic activities can still only be obtained for a few select muscles and under highly restrictive laboratory conditions. Therefore, accurate predictions of individual muscle forces during human movements will remain a challenge for the future.Less
The control of joint movements through muscles represents a mathematically redundant problem: that is, there are more muscles than are strictly required for a given task. However, despite this apparent redundancy, movements are performed with a stereotypical pattern of muscle activation and synergistic force sharing. Through direct measurement of multiple muscle forces in freely moving animals, this chapter demonstrates that force sharing patterns depend crucially on the mechanical properties of the muscles: the force-length and force-velocity relationships. Using optimal control theory, force sharing patterns can now be predicted confidently when the mechanical properties of the muscles and their instantaneous contractile conditions are accurately represented in the cost functions used to determine force sharing patterns. Although the mechanical properties and instantaneous contractile conditions of muscles are easy to determine in animal models of motor control, force-length and force-velocity properties for individual human skeletal muscles are still hard to obtain, and the instantaneous contractile properties of in vivo human muscle fascicles during dynamic activities can still only be obtained for a few select muscles and under highly restrictive laboratory conditions. Therefore, accurate predictions of individual muscle forces during human movements will remain a challenge for the future.
Daniel Kernell
- Published in print:
- 2006
- Published Online:
- September 2009
- ISBN:
- 9780198526551
- eISBN:
- 9780191723896
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198526551.003.0002
- Subject:
- Neuroscience, Molecular and Cellular Systems
This is a tutorial chapter, mainly aiming to introduce the neuromuscular system. Treated items include basic aspects of skeletal muscle and peripheral axon physiology, principles of sensory and motor ...
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This is a tutorial chapter, mainly aiming to introduce the neuromuscular system. Treated items include basic aspects of skeletal muscle and peripheral axon physiology, principles of sensory and motor muscle innervation, and (very briefly) some general points concerning motor functions of the central nervous system. For muscles, items include: muscle metabolism, excitation-contraction coupling, and the mechanisms for force generation. For axons, items include: intra-axonal transport processes, membrane properties, and the mechanisms and speed of the axonal conduction of action potentials (spikes). The different motor unit and muscle fibre types of limb muscles are introduced and a brief description is given of electromyographic techniques for recording motor unit activity.Less
This is a tutorial chapter, mainly aiming to introduce the neuromuscular system. Treated items include basic aspects of skeletal muscle and peripheral axon physiology, principles of sensory and motor muscle innervation, and (very briefly) some general points concerning motor functions of the central nervous system. For muscles, items include: muscle metabolism, excitation-contraction coupling, and the mechanisms for force generation. For axons, items include: intra-axonal transport processes, membrane properties, and the mechanisms and speed of the axonal conduction of action potentials (spikes). The different motor unit and muscle fibre types of limb muscles are introduced and a brief description is given of electromyographic techniques for recording motor unit activity.
John J. Videler
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780199299928
- eISBN:
- 9780191714924
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199299928.003.0007
- Subject:
- Biology, Ornithology
Movements of the skeleton of a starling in flight visualized with high speed X-ray film techniques provide 3-D insight on internal wing beat dynamics. The timing of electrical activities (EMGs) of ...
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Movements of the skeleton of a starling in flight visualized with high speed X-ray film techniques provide 3-D insight on internal wing beat dynamics. The timing of electrical activities (EMGs) of the larger flight muscles in flight is presented in relation to the different phases of the wing beat cycle. The pectoralis is responsible for the downstroke of the wing and for forward rotation (pronation) of the humerus. Forces are measured directly at the insertion on the deltopectoral crest, allowing mechanical power estimates in flight at different speeds. The supracoracoideus muscle is not only involved in powering the upstroke, but also plays an important role in the backward rotation (supination) of the wings. The timing of EMG activity in tail muscles during walking and flight reveals complex kinematic patterns. The relationship with force production remains unclear. Measurements of pressure changes in the anterior air sacs reveal a complex relationship with respiration.Less
Movements of the skeleton of a starling in flight visualized with high speed X-ray film techniques provide 3-D insight on internal wing beat dynamics. The timing of electrical activities (EMGs) of the larger flight muscles in flight is presented in relation to the different phases of the wing beat cycle. The pectoralis is responsible for the downstroke of the wing and for forward rotation (pronation) of the humerus. Forces are measured directly at the insertion on the deltopectoral crest, allowing mechanical power estimates in flight at different speeds. The supracoracoideus muscle is not only involved in powering the upstroke, but also plays an important role in the backward rotation (supination) of the wings. The timing of EMG activity in tail muscles during walking and flight reveals complex kinematic patterns. The relationship with force production remains unclear. Measurements of pressure changes in the anterior air sacs reveal a complex relationship with respiration.
Lynette A. Jones and Susan J. Lederman
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780195173154
- eISBN:
- 9780199786749
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195173154.003.0002
- Subject:
- Psychology, Cognitive Neuroscience
This chapter considers the evolutionary development of the hand within the context of changes in the structure and function of primate hands. The differences between modern human and nonhuman primate ...
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This chapter considers the evolutionary development of the hand within the context of changes in the structure and function of primate hands. The differences between modern human and nonhuman primate hands are discussed with reference to tool use and manufacture. The anatomical structure of the human hand is reviewed in terms of the bones, joints, and muscles that comprise the hand and of the structure of the skin that overlies the palmar and dorsal surfaces. The sensory and motor innervation of the human hand is also explained. The chapter concludes with a summary of some of the biomechanical models of the hand that have been developed.Less
This chapter considers the evolutionary development of the hand within the context of changes in the structure and function of primate hands. The differences between modern human and nonhuman primate hands are discussed with reference to tool use and manufacture. The anatomical structure of the human hand is reviewed in terms of the bones, joints, and muscles that comprise the hand and of the structure of the skin that overlies the palmar and dorsal surfaces. The sensory and motor innervation of the human hand is also explained. The chapter concludes with a summary of some of the biomechanical models of the hand that have been developed.
Daniel Kernell
- Published in print:
- 2006
- Published Online:
- September 2009
- ISBN:
- 9780198526551
- eISBN:
- 9780191723896
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198526551.003.0009
- Subject:
- Neuroscience, Molecular and Cellular Systems
The functional properties of neurones, synapses, and muscles often change as a result of preceding use. In the short term (minutes to hours), such changes are typically rather rapidly reversible and ...
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The functional properties of neurones, synapses, and muscles often change as a result of preceding use. In the short term (minutes to hours), such changes are typically rather rapidly reversible and may be expressed as either a net increase (potentiation) or a net depression (fatigue) of input-output relations. For voluntary motor activity, such changes may take place within (e.g., central fatigue) as well as outside (e.g., peripheral fatigue) the central nervous system. In such activity, an increasing degree of muscle and/or central fatigue will be experienced as an increasing sense of effort needed for continued action. In muscle physiology a distinction is made between high- and low-frequency fatigue, and extensive studies have been performed as to the role of energy metabolism, cross-bridge interactions, excitation-contraction coupling and neuromuscular transmission. The various manners in which motoneurone properties are matched to muscle characteristics might help to counteract fatigue-related declines of motor output.Less
The functional properties of neurones, synapses, and muscles often change as a result of preceding use. In the short term (minutes to hours), such changes are typically rather rapidly reversible and may be expressed as either a net increase (potentiation) or a net depression (fatigue) of input-output relations. For voluntary motor activity, such changes may take place within (e.g., central fatigue) as well as outside (e.g., peripheral fatigue) the central nervous system. In such activity, an increasing degree of muscle and/or central fatigue will be experienced as an increasing sense of effort needed for continued action. In muscle physiology a distinction is made between high- and low-frequency fatigue, and extensive studies have been performed as to the role of energy metabolism, cross-bridge interactions, excitation-contraction coupling and neuromuscular transmission. The various manners in which motoneurone properties are matched to muscle characteristics might help to counteract fatigue-related declines of motor output.
Daniel Kernell
- Published in print:
- 2006
- Published Online:
- September 2009
- ISBN:
- 9780198526551
- eISBN:
- 9780191723896
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198526551.003.0010
- Subject:
- Neuroscience, Molecular and Cellular Systems
This chapter is concerned with the slow processes and cellular adaptations taking place after the transection of motor axons. For axotomized motoneurones, changes occur in their morphology, membrane ...
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This chapter is concerned with the slow processes and cellular adaptations taking place after the transection of motor axons. For axotomized motoneurones, changes occur in their morphology, membrane properties, and synaptic cover. Denervated muscle fibres become atrophic and weak, their membrane properties are altered and they may become spontaneously active (fibrillation). After transection, peripheral motor axons will regenerate and, ultimately, reinnervate denervated muscle fibres that they might come across. Such reinnervation will promote a change of muscle fibre properties back toward normal. In very young mammals, but generally not in adults, regenerating peripheral axons may be (partly) capable of finding their own original target muscles. Properties of muscle fibres may change after reinnervation by types of motoneurones other than their original ones (cross-reinnervation experiments). In partially denervated muscles, collateral reinnervation may occur by sprouting of new collaterals from surviving motor axons.Less
This chapter is concerned with the slow processes and cellular adaptations taking place after the transection of motor axons. For axotomized motoneurones, changes occur in their morphology, membrane properties, and synaptic cover. Denervated muscle fibres become atrophic and weak, their membrane properties are altered and they may become spontaneously active (fibrillation). After transection, peripheral motor axons will regenerate and, ultimately, reinnervate denervated muscle fibres that they might come across. Such reinnervation will promote a change of muscle fibre properties back toward normal. In very young mammals, but generally not in adults, regenerating peripheral axons may be (partly) capable of finding their own original target muscles. Properties of muscle fibres may change after reinnervation by types of motoneurones other than their original ones (cross-reinnervation experiments). In partially denervated muscles, collateral reinnervation may occur by sprouting of new collaterals from surviving motor axons.
Daniel Kernell
- Published in print:
- 2006
- Published Online:
- September 2009
- ISBN:
- 9780198526551
- eISBN:
- 9780191723896
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198526551.003.0011
- Subject:
- Neuroscience, Molecular and Cellular Systems
This chapter deals with long-term (weeks, months) changes in the properties of motoneurones and muscle fibres after disuse or after various patterns of enhanced activity. In voluntary motor activity ...
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This chapter deals with long-term (weeks, months) changes in the properties of motoneurones and muscle fibres after disuse or after various patterns of enhanced activity. In voluntary motor activity the optimal parameters differ between endurance training and force training. Chronic electrical stimulation of whole muscles during long times per day causes muscles to become more fatigue resistant; muscle contractions may also become slower and there are corresponding alterations in myosin composition and muscle histochemistry. Long-term effects of pulse rate on muscle speed are inconsistent and muscles may become slowed down also by physiologically fast rates. Many of the denervation-elicited changes of membrane and other muscle properties may become counteracted and reversed by chronic muscle stimulation. Also properties of motoneurones are influenced by training and by chronic stimulation of motor nerves, but less dramatically so than their muscle fibres. Changes in motoneurones include alterations of their afterhyperpolarization and other membrane properties.Less
This chapter deals with long-term (weeks, months) changes in the properties of motoneurones and muscle fibres after disuse or after various patterns of enhanced activity. In voluntary motor activity the optimal parameters differ between endurance training and force training. Chronic electrical stimulation of whole muscles during long times per day causes muscles to become more fatigue resistant; muscle contractions may also become slower and there are corresponding alterations in myosin composition and muscle histochemistry. Long-term effects of pulse rate on muscle speed are inconsistent and muscles may become slowed down also by physiologically fast rates. Many of the denervation-elicited changes of membrane and other muscle properties may become counteracted and reversed by chronic muscle stimulation. Also properties of motoneurones are influenced by training and by chronic stimulation of motor nerves, but less dramatically so than their muscle fibres. Changes in motoneurones include alterations of their afterhyperpolarization and other membrane properties.
Christopher L.-H. Huang
- Published in print:
- 1993
- Published Online:
- March 2012
- ISBN:
- 9780198577492
- eISBN:
- 9780191724190
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198577492.001.0001
- Subject:
- Neuroscience, Molecular and Cellular Systems
This book provides a review of developments made in the understanding of cellular activation phenomena in striated muscle. Basic physical, mathematical, and physiological principles are covered. The ...
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This book provides a review of developments made in the understanding of cellular activation phenomena in striated muscle. Basic physical, mathematical, and physiological principles are covered. The book consistently draws correlations both with cellular and molecular biological information, and their physiological consequences and significance. It is accessible both as a survey of basic concepts and as an authoritative review of recent work in the field. The book succeeds in explaining complex biophysics in such a way that the non-expert reader obtains insights into the molecular mechanisms of muscle activation and their control mechanisms, as well as in providing the expert with the detailed mathematical and experimental evidence.Less
This book provides a review of developments made in the understanding of cellular activation phenomena in striated muscle. Basic physical, mathematical, and physiological principles are covered. The book consistently draws correlations both with cellular and molecular biological information, and their physiological consequences and significance. It is accessible both as a survey of basic concepts and as an authoritative review of recent work in the field. The book succeeds in explaining complex biophysics in such a way that the non-expert reader obtains insights into the molecular mechanisms of muscle activation and their control mechanisms, as well as in providing the expert with the detailed mathematical and experimental evidence.
