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Studies on the mammalian muscle spindle

The subjects of these studies are the major components of the mammalian muscle spindle, which is an encapsulated proprioceptor serving to monitor skeletal muscle length and length change. Those components are: specialized intrafusal muscle fibres; sensory nerve endings that form intimate contacts with the intrafusal fibres; and motor nerve fibres by means of which the central nervous system can exercise control over the sensitivity of the spindle. My first important contribution was to establish the number of types of intrafusal fibre (1-8, 11). Their different mechanical properties help to shape the responses of the sensory endings in characteristic ways (papers 15 and 42). Detailed reconstructions of sensory endings revealed recognizable features of the primary ending that were consistently associated with the different intrafusal fibres (10, 13, 18, 20, 33). The sites of nerve impulse generation and coding are being studied in relation to the branching pattern of the sensory nerve fibres (45, 50, 55). Analysis of the innervation of individual spindles has revealed the interplay of random and deterministic factors in spindle construction (20, 36, 37, 40, 41, 44, 48, 52, 53). As yet it is unknown how the differences that exist between muscles in this respect are related to their specific roles in motor control or kinaesthesia. However, reflex activity appears to be grossly disturbed in muscles that have been reinnervated following nerve section, since functional endings may be formed in inappropriate locations (22, 25, 28- 31,34, 38, 39, 43, 46). The motor innervation of the spindle was for long controversial, especially concerning the distribution of the different functional categories of axon. I have pursued histophysiological and probabilistic approaches to this problem, about which there now appears to be a large measure of agreement in favour of my conclusions (9, 12, 19, 21, 23, 26, 27, 35, 41, 42, 44, 48, 49). Papers 1-6 in the following list are based on work that originally formed part of a thesis presented in candidature for the degree of Ph. D. in the Faculty of Medicine, University of Sheffield. For each full paper of which 1 am a co-author an estimate of my contribution to the overall effort is given as a percentage in the list.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:600913
Date January 1994
CreatorsBanks, Robert William
PublisherDurham University
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://etheses.dur.ac.uk/9594/

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