[Functional properties of the Golgi tendon organs].
Golgi tendon organs are encapsulated mechanoreceptors present at the myo-tendinous and myo-aponeurotic junctions of mammalian skeletal muscles. Within the tendon organ capsule, the terminal branches of a large diameter afferent fibre, called Ib fibre, are intertwined with collagen bundles in continuity with tendon or aponeurosis at one end. The other end is connected with a fascicle of 5-25 muscle fibres, contributed by several motor units. The contraction of these fibres, exerting strain on the collagenous bundle and causing deformation of sensory terminals, is the adequate stimulus of the tendon organ. For this stimulus, the tendon organ has a very low threshold, so that a single fibre twitch can elicit a discharge from the receptor. A tendon organ can thus signal the contraction of a single one of the 10-15 motor units which contribute fibres to the fascicle connected with the receptor. The number of tendon organs present in a muscle, taken together with the fact that a given motor unit can activate several tendon organs, strongly suggests that the contraction of every motor unit in this muscle is monitored by at least one tendon organ. The exact nature of the information provided by tendon organs to the central nervous system remains an open question because no simple relation could be established between the discharge frequency of a receptor and the contractile forces of its activating motor units. It is known, however, that, due to their dynamic sensitivity, tendon organs are efficient in signaling rapid variations of contractile force. The dynamic parameters of muscle contraction prevail in the information carried by afferent discharges from tendons organs.
Jami
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Laboratoire de Neurophysiologie, Collège de France, Paris.
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D004594:Electrophysiology; D006057:Golgi-Mazzoni Corpuscles / Q000033:anatomy & histology / Q000502:physiology*; D006801:Humans; D008465:Mechanoreceptors / Q000502:physiology*; D009119:Muscle Contraction; D009132:Muscles / Q000294:innervation*; D009469:Neuromuscular Junction / Q000502:physiology; D013710:Tendons / Q000294:innervation*
Propriétés fonctionnelles des organes tendineux de Golgi.